Developmental Psychology

Are Infants Born Prepared For Learning? The Case for Natural Pedagogy

jgoldman — Thu, 28 Apr 2011 08:30:00 +0000

Are Infants Born Prepared For Learning? The Case for Natural Pedagogy

What is learning?

Most psychologists (indeed, most people in general) would agree that learning is the acquisition of new knowledge, or new behaviors, or new skills. Hungarian psychologists Gergely and Csibra offer a deceptively simple description: "Learning involves acquiring new information and using it later when necessary." What this means is that learning requires the generalization of information to new situations - new people, objects, locations, or events. The problem is that any particular piece of information that a human or animal receives is situated within a particular context. Learning theorists refer to this as the problem of induction. Most learning theories invoke statistical learning mechanisms to account for this: as infants or animals have experiences in the world, they can identify correlations among events or encounters, and use those statistical correlations to form the basis of generalizations for novel events or encounters. However, this does not explain the situations in which infants rapidly learn information after only one or a few instances - certainly not enough time for any statistical learning mechanism to provide reliable information. Human communication might provide a shortcut.

Gergely and Csibra offer the following examples:

If I point at two aeroplanes and tell you that 'aeroplanes fly', what you learn is not restricted to the particular aeroplanes you see or to the present context, but will provide you generic knowledge about the kind of artefact these planes belong to that is generalizable to other members of the category and to variable contexts... If I show you by manual demonstration how to open a milk carton, what you will learn is how to open that kind of container (i.e. you acquire kind-generalizable knowledge from a single manifestation). In such cases, the observer does not need to rely on statistical procedures to extract the relevant information to be generalized because this is selectively manifested to her by the communicative demonstration.

The key here is that the learner does not need to statistically infer the generalizable information. Rather, the generalizability of the information is indicated within the communicative interaction itself. You don't tell the child "that airplane is flying"; you say "airplanes fly." This sort of teaching is not restricted to linguistic communication, as in the case of the milk carton.

What Gergely and Csibra are hypothesizing is that human communication is an evolutionary adaptation designed to aid in the transmission of generic knowledge between individuals. Specifically, they speculate that the emergence of tool-making led to the selection for the capacity for the communication of generic knowledge, during hominin evolution. The argument is that observational learning mechanisms would not be sufficient for the cognitively opaque process of making and using tools.

What does this mean?

Chimpanzees use tools. While this used to be a somewhat surprising revelation, this is not so surprising anymore. But their tool use is limited in important ways. They choose suitable tools for a given task from the immediate surroundings, sometimes modifying them, and then they generally discard the tool after they're done with it. In a sense, they're using tools as answers to the question "what object could I use to achieve this specific goal?" One common example of tool use in chimps involves using two objects as hammer and anvil to break apart nuts. Watch the juvenile chimp in this video learn about this process from her mother (that segment begins around 2:15):

Early humans may have had a slight shift in the way they thought about tools. Tools were kept rather than discarded, and often stored in particular locations. Tools could be made at one place, and carried to another place to be used. Rather than asking "what object can i use to achieve this specific goal," as a chimpanzee would, the human might ask, "for what purpose might I use this object?"

The problem is that any new member of a given culture (such as a child) would have to learn the function of tools. Trial-and-error is a slow and somewhat clunky process, and it might lead to various useful ways of interacting with tools, but probably not the intended use of a given tool. Trial-and-error is also unlikely to reveal the function of tools on other tools (such as a screwdriver and a screw, unless you have both tools in front of you), or the future function of a given tool in a different place or context.

A social learning mechanism such as imitation can get you part of the way there - and, indeed, in chimpanzees and other non-human animals it does. One could observe another individual use a tool and infer the function of the tool from the outcome. But this sort of learning mechanism is also limited: you need to observe an immediately obvious outcome in order to determine the goal of a given set of behaviors.

But even simple observation and imitation won't entirely solve the problem. For example, imagine someone using a tool to carve a piece of wood. What is the goal of this behavior? To take a big piece of wood and turn it into smaller pieces of wood? To make sounds? To make a carving? Without some prior knowledge of the tool, it is difficult to figure out what it is used for.

Or for another example, what is this?

When I asked on twitter, I got responses ranging from "bottle opener" to something with which to "beat the snot out of someone" else (twice). One person thought it could be used to measure something, and another thought it was a strange cookie cutter. One guess confused even me. Surely anybody could come up with a dozen potential uses for the item, but there is only one function that is was designed to fulfill: it's an antique pot cover lifter, designed to remove hot lids from their bases. You thread your fingers through it, and use it as a hook (if the lid has a handle), or you wedge the cover in there to lift it away.

Observing someone's behavior isn't as straightforward as you might think. Behavior can always be explained by an infinite combination of mental states, goals, and background knowledge, and is rarely (if ever) transparent with respect to the goals of a given action or the background knowledge that informs that action. This problem could be solved, however, if the tool user makes some of this information explicit. Some aspects of a behavior can be emphasized and others can be ignored, and products can be distinguished from by-products. But the learner must be receptive to this information for learning to take place at all.

Is it possible that evolution has prepared humans to learn generalizable information? Gergely and Csibra think so. They hypothesize that a specialized innate pedagogy mechanism (the pedagogical learning stance) is in place that allows an individual to remember generic information, which becomes generalizable to other contexts. A cognitive system like this requires three things. First, the learner must understand the communicative intent of the teacher via ostensive cues. Second, the teacher and learner must be able to use referential signals (things like eyegaze and pointing) to facilitate joint attention on a given object or location. Third, the learner must be able to comprehend the information content of the interaction; they must assume they are getting relevant information.

For their hypothesis to hold, infants should be sensitive to ostensive cues. In other words, they need to know that they are being addressed. The developmental psychology literature is rife with evidence that infants indeed possess this ability. For example, infants prefer to look at faces with directed gaze over faces with averted gaze. Further, the infant brain responds to a smile from another individual only if there is mutual eye-contact, and not if the smiler is looking elsewhere. Another ostensive cue is infant-directed speech, or baby-talk or "motherese." Newborn infants prefer listening to infant-directed speech over adult-directed speech. One particularly fascinating line of research has demonstrated that parents also adjust their actions themselves when engaged in a pedagogical interaction with their children, and infants prefer this "motionese" to adult-directed motion (this has also been found in macaques!). This fulfills the first requirement: that the learner must identify the communicative intent of the teacher.

The second requirement, that learners must understand the referential signals provided by their teachers, is also fairly straightforward. Preverbal infants aren't able to use linguistic information (or really, any symbolic system) in a robust way, but they are able to use actions such as pointing or the shifting of eyegaze towards an object in order to facilitate shared attention. Infants follow the gaze of social partners from very early on in development (as early as three months), and moreover, they are more likely to do so if the gaze-shift is preceded by an ostensive signal such as eye-contact or infant-directed speech. In other words, first the teacher must get the attention of the learner using ostensive cues, and then the teacher must redirect the learner's attention to a particular object or location using referential signals. This fulfills the second requirement: that the learner must be able to interpret the referential signals provided by the teacher.

The third requirement is that learners must understand that they are going to learn generic information. In other words, children would expect to learn something generalizable when in the context of ostensive-referential communication, rather than simply gaining episodic facts that pertain only to the specific context in which the social interaction occurs. Gergely and Csibra point out that this is what separates their hypothesis from other competing hypotheses (such as that of Michael Tomasello), which suggest that human communication derives from the desire to cooperate with others in order to achieve shared goals. If this was the case, then infants should treat generic information about an object (such as an object's visual appearance) differently than episodic information about that same object (such as an object's location). One recent study provided evidence to support this. In a non-communicative context, infants are more likely to notice a change in an object's location than in it's appearance. That is, they are giving preferential attention to episodic here-and-now information. However, when provided ostensive-referential communication, they are more likely to notice a change in an object's identity rather than it's location - they are attending to generic information rather than episodic information. This fulfills the third requirement: that the ostensive cues and referential signals prepare the infant to learn generalizable information from the teacher - they put the infant into "learning mode."

This is all very good evidence that humans do have a form of natural pedagogy, and that it is innate. But in order to make the case for pedagogy to be an evolutionary adaptation in the hominin lineage, as Gergely and Csibra are claiming, three additional types of support are necessary: (1) that natural pedagogy is human-specific, (2) that natural pedagogy is universal among human cultures, and (3) that this sort of human social communication was explicitly selected for in evolution, rather than having emerged as a by-product of some other selection.

The next set of posts in this series will address these questions.

See Part 1: Perseverating on Perseverative Error: What Does The "A-not-B Error" Really Tell Us About Infant Cognition?

For more on social learning:
How Do You Figure Out How Chimps Learn? Peanuts. and More on Chimpanzees and Peanuts
Ed Tronick and the "Still-Face Experiment"

Csibra, G., & Gergely, G. (2009). Natural pedagogy Trends in Cognitive Sciences, 13 (4), 148-153 DOI: 10.1016/j.tics.2009.01.005

Image via Flickr/19melissa68

jgoldman Thu, 04/28/2011 - 04:30

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Fascinating piece. I wonder if tool making can be viewed as a broader category than it typically is.

I often wonder if one of the earliest human artifacts would have been some kind of container (a primitive basket) for collecting gathered food items to transport back to camp. This certainly beats being limited to carrying what you can hold in your hands. Perhaps there were also similar containers for women to carry their infants while they're gathering food items.

These items could have been made with or without tools, or maybe they could be considered tools themselves.

Unfortunately, objects like these rot (unlike stone tools), so we may never know what else was in the early human toolkit besides hard objects like stone (or possibly antler and wood).

Great post. I often get frustrated with the dogs I work with because they are incapable of generalizing this kind of things, and they need repetition, repetition, repetition. My clients have the same feeling, too!
And I'm with Charles Sullivan in the container bit, you just have to watch what toddlers like the most: taking things and getting them into holes/containers! that must be really hardwired.

I wonder how appropriation fits with this. I'm thinking of groups such as native Americans, who found the cloth sacks that flour rations came in to be more valuable than the flour, which they dumped on the ground. The cloth was used for clothing. The cast off objects of the developed world are readily repurposed into tools and useful objects by poor people, or stripped down to raw materials. The ability to see new uses for objects seems critical to human culture. It's an ability that we need right now in a crisis of stubborn refusal to replace old technologies with new ones.

Interesting stuff. I've just taken a very quick look at the paper, but it seems to me that you're right that the authors have a ways to go to demonstrate that learning by induction is an adaptation, let alone one associated with the emergence of tool-making.

One problem an evolutionary account of the emergence of a particular cognitive trait will have is that we usually don't know enough about the physical/social environment in which the trait arose to be able to determine how plausible an adaptive explanation truly is.

I am interested in the future evolution of human brain development. What I have been contemplating recently is the possible impact world-wide access to school would have on the human brain. Of course, many doubt the effectiveness of schooling, however I would say that we would have to compare what our brains are doing now with what they did thousands of years ago, not 50 years or less. In this case, the human brain is being put through continuous stimuli attacks, whether good or bad. Thousands of years ago, the stimulus was different, not less. But, as people continue to use science and mathematics to understand our world and even the galaxy and universe, what would this do to our brain and the so-called natural Pedagogy. As more and more young peole are exposed to massive amounts of stimuli, it would be wise for education to take the role of an "information organizer." People are exposed to information on a daily basis, essentially an education. But, this information needs to be organized with unnatural attention since much of the information we obtain today is unnatural itself. We are not hunting for a living or seeking out water sources, but we are investigating science, teaching our youth, organizing business meetings, inventing new technologies, using the internet to talk, using writing to talk.... all of which we didn't do a few thousand years ago. Even writing was only for a hand full of people less than 100 years ago. The future of brain evolution and thus education is a fascinating one that I hope more people decide to include themselves in.

One problem an evolutionary account of the emergence of a particular cognitive trait will have is that we usually don't know enough about the physical

Natural pedagogy is human-specific? Huh? I use similar techniques to train my adult cats... get their attention, model the behavior (or make them model the behavior, such as rubbing their front claws against the scratching post), reward the behavior, repeat 10-12 times. They learn. They want to learn.

Along with that I have to make sure I use other pedagogical techniques that cats respond to well, such as distracting them by gently removing them from the area where they are engaging in incorrect behavior (such as an upholstered chair), catching them at the time of the incorrect behavior rather than waiting until afterwards, using a sudden sound as an unpleasant association, training them to stop and drop when they hear "no"... and above all, understanding what cats are never going to be able to learn, such as to follow a pointing finger, or understanding they are not interested in anything unrelated to food when they are four months old.

It's hard to look at a cat and see something that responds to training. I've heard it said that you can only teach a cat something it was interested in doing anyway, but the only scratches in my house have been on the scratching posts for five years. I never have to hit them. I must know something.

Maybe cats "learn to learn" as they grow older. But don't humans?

As far as cats learning after one or two demonstrations, I have observed this in mine. In a playful mood, I let one of mine drink from a bathroom faucet just one time three years ago, and never again, but he still scratches bathroom faucets vigorously and meows at me (not to himself or to the faucet, but directly at me). He learned after one time. What he doesn't manage to put together is that I never let him do it again.

One problem an evolutionary account of the emergence of a particular cognitive trait will have is that we usually don't know enough about the physical

I found this most interesting, although as I did not retain my academic affiliations on retiring I was unable to access the paper by Csibra and Gergely. When I was trying to develop a language for communicating between humans and a novel âwhite boxâ information processing system many years ago I was too tied up with the technology. For various reasons the research was abandoned but recently I have been looking at my old ideas and am finding that my research probably had more in common with ideas on the evolution of communication in humans than with conventional algorithmic computing.

I very much like the idea that human communication is an evolutionary adaptation designed to aid in the transmission of generic knowledge between individuals. My approach was basically to devise a language to name objects and relate them together in a semantic framework. The processor was a routine which matched objects with a âshort term memoryâ of current object descriptions, in a way that involved the recursive scanning of sets, and partitions of sets.

The relevance is that if you describe objects as members of a hierarchy of sets, what you are actually doing is to make generalisations. It would seem that move from specific knowledge of individual items to generic knowledge is related to the ability to classify the objects into named sets. Such a step is important for efficient communication between generations, and essential for the development of language.

I will definitely be considering the idea expressed here as part of the reassessment om my earlier research.

As a trainer, I found the reference to generalizable information very interesting. These same 3 principles apply to adult learners as well that they need to understand that trainer is addressing them, get the attention by signals and that the information must be relevant.

Infants, in fact, seem far more open to receiving information and generalizing it than adults.

"The third requirement is that learners must understand that they are going to learn generic information"

I wonder if this could be the source, as in formal business training adults expect episodic and not generic information to be presented?

Such a step is important for efficient communication between generations, and essential for the development of language.

I will definitely be considering the idea expressed here as part of the reassessment om my earlier research.

Infants may be wired ready to learn, but it's probably an orienting towards more reinforcing stimuli. Just like infants prefer curved, round shapes over other shapes, they probably prefer certain kinds of movements tones. This would definitely appear as if they knew they were being addressed.

I don't think that infants are prepared to receive information that can be generalized. They are prepared to receive functional information. If a characteristic of an object changes, there would be less functional change, generally, than if it was moved. The infant learns functional qualities as they relate to their action memory, like that which is found through mirroring another through observation, and the infant sees shapes, and very simple stimuli, that it associates with the infant's own ability to manipulate the object. Shape and position would be very salient to a infant as these are the most important to their ability to interact with that object. This would give the appearance of generalizing.

Perseverating on Perseverative Error: What Does The "A-not-B Error" Really Tell Us About Infant Cognition?

jgoldman — Mon, 25 Apr 2011 08:15:00 +0000

Perseverating on Perseverative Error: What Does The "A-not-B Error" Really Tell Us About Infant Cognition?

There's a very well-known experiment in developmental psychology called the "A-not-B task." The experiment goes something like this: you, the experimenter, are seated opposite a human infant. Within the reach of both you and the child are two boxes: box "A," and box "B." You hide a toy in "A," in full view of the infant. As expected, the infant reaches for "A" to retrieve the toy. You repeat the process several times. Each time you hide the toy in "A," and each time the infant reaches for "A" to find the toy. Experimental set-ups like this are extremely common in infant and animal studies. When trying to determine how a young baby - barely able to interact with you or the world - thinks about the world, you've really got two options: design an experiment that relies on the infant's ability to direct his or her eye gaze to a given location, or one that relies on the infant's ability to (somewhat clumsily) reach towards a given location.

So you keep hiding the toy in "A" and the baby keeps searching for the toy in "A." Simple enough. But what happens if you suddenly hide the toy in "B"? Remember, you're hiding the toy in full view of the infant. An older child or an adult would simply reach for "B" to retrieve the toy. But not the infant. But, despite having just seen the object hidden in the new "B" location, infants between 8 and 12 months of age (the age at which infants begin to have enough motor control to successfully reach for an object) frequently look for it under box "A," where it had previously been hidden. This effect, first demonstrated by Jean Piaget, is called the perseverative search error or sometimes the A-not-B error.

The A-not-B error is one of the most replicated findings in developmental psychology, but it seems almost as if for every time the experiment and results have been replicated, there has been a new explanation presented for why the error itself even occurs. Piaget thought that the existence of the object under A is causally related to the search response itself. That is, independent of where the object was hidden, searching under A would result in the object being found at A. In other words, he thought that the error reflected the immaturity of the child's understanding of object permanence, which is the understanding that objects continue to exist even after they become hidden. When a ball rolls under a couch, according to Piaget, an infant with incomplete object permanence would behave as if the object ceased to exist since it is no longer visible. Other more recent explanations have suggested that the infants are unable to inhibit a previously rewarded motor response, perhaps reflecting the immaturity of the prefrontal cortex, or that the error is due to limitations on working (short-term) memory. Others have suggested that infants are unable to switch their attention from location A to location B, presumably also due to underdeveloped executive functioning in the prefrontal cortex. This would reflect perseveration in attention rather than in search behavior, per se. Yet others have implicated the putative mirror neuron system to explain the error.

When experiments get replicated, even under the best of circumstances, there are minor tweaks in the way the experiment is conducted, like in the game telephone. What is especially remarkable, then, about the A-not-B error is that despite the methodological differences in conducting the experiment, the results are extremely consistent. Even if developmental and cognitive psychologists can't agree on why the error occurs, that it occurs is certain. But a finding without a solid explanation isn't particularly useful, is it?

One way to better determine the reason for the A-not-B error would be to find a way to break it. This isn't necessarily a ground-breaking idea: the common errors children make when learning to read, for example, tell us important things about the process of learning to read. When Dan Simons and Chris Chabris discovered inattentional blindness - essentially a breakdown in the attention system - that told researchers something really important about how attention works in the first place. So, are there any circumstances under which an infant under 12 months of age would reliably pass the test, and search for the toy at location B on the B trials?

A group of researchers from Hungary, including Hungarian rockstar developmental psychologists GyoÌrgy Gergely and Gergely Csibra (confusing, I know...), began by identifying the one feature of the experimental methodology that was certain to be included in every A-not-B experiment ever conducted: baby-talk. Even the most stodgy, grumpy, curmudeonly human adult can't help but use baby-talk (or, formally, infant-directed speech) when interacting with a baby. More generally, the task always occurs in a social-communicative context. When the experimenter hides the object each time in location A, it is accompanied by things like eye-contact, addressing the baby by name, looking back and forth between the infant and the hiding location, and baby-talk. These are called ostensive and referential signals. Is it possible that over fifty years of replicated results on the A-not-B error comes down, essentially, to baby-talk?

This isn't as far-fetched as it might sound. Previous findings have indicated that these ostensive-referential communicative signals could be interpreted by the infant in a special sort of way. Gergely and Csibra suggested that these sorts of social cues could activate within the infant what they called a "pedagogical learning stance." In other words, they could prepare the infant to go into "learning mode." Infants, after all, learn just about everything about their culture from their parents and other caretakers. But given how much sensory and social input they get, they must have a way of determining what social interactions are designed to confer generalizable information about the world as opposed to episodic information that relates only to the immediate situation.

Most researchers (Piaget included) have treated the hiding behaviors in the A-not-B experiment as indicative of episodic information about the location of the toy - something like, "the toy is under box A." But if researchers always provide ostensive-referential communicative cues while conducting the experiment, Gergely and Csibra, along with JoÌzsef TopaÌl, AÌdaÌm MikloÌsi, and AÌgnes ErdoÌhegyi, hypothesized that the infants are actually interpreting the information as generalizable rather than episodic - something like, "objects like this toy tend to be found under box A." If this is in fact the kind of information that the baby is receiving, then it is indeed reasonable for the baby to continue searching for the object at location A, even if she has seen it hidden at B. The hiding of the toy at location B is more like a statistical outlier, in this case. This would make the A-not-B error not an error at all, but a feature of the pedagogical learning system!

In order to test this, the team recreated the standard A-not-B task, but they added two important conditions. The standard condition included the ostensive-referential signals as usual: the researchers made eye-contact with the infant, greeted him or her by name, used infant-directed speech, and continually shifted her gaze from the infant to the hiding location and back. In the non-communicative condition, the researcher performed the experiment exactly as usual, but without any of the ostensive-referential cues. While all of her actions were completely visible, she never made eye-contact and never spoke to the baby. A third condition removed the social partner entirely from the set-up. The movement and hiding of the object was the same, but the experimenter conducted the entire experiment from behind a curtain. In each condition, there was a four-second delay between the hiding of the object, and the infant being permitted to search for the object. In each condition, the toy was first hidden four times at A, and then three times at B. Different ten-month-old babies participated in each different condition, with a total of fourteen per condition, for a total of 42 infant participants (these numbers are typical for infant studies).

If the pegagogy explanation for the A-not-B error is correct, then there should have been fewer errors made in the non-communicative and non-social conditions, compared with the standard ostensive-referential communicative condition. Indeed, this is what was found! In the ostensive-referential condition, infants succeeded in finding the toy on only on 14% of the B-trials (the black bars in the figure below). In other words, 86% of infants committed the standard A-not-B error in this condition, as expected. In the non-communicative condition, in which the experimenter was present but did not socially engage with the infants, far fewer of the infants made the A-not-B error. In this case, 57% of infants successfully found the toy in B trials. In the non-social condition, in which the social partner was entirely absent, 64% of infants successfully found the toy on the B trials. Not only was the proportion of successful B-trial searches statistically significantly higher in the non-communicative and non-social conditions, compared with the ostensive-referential condition, but in the non-social condition, there was no longer a statistical difference between the proportion of successful A-trials and successful B-trials!

The interpretation of these results is pretty straightforward: by removing the social-communicative cues and not talking to babies using baby-talk, Piaget's classic A-not-B error can be reduced or eliminated. To be clear, these findings are not consistent with the generally-accepted explanations for the error: lack of object permanence, reduced working memory, or the inability to inhibit previously learned motor responses. These findings are also inconsistent with the mirror neuron explanation, because both the ostensive-referential condition as well as the non-communicative condition included the same amount of visual and motor experience. Instead, the A-not-B error is not an error at all, but a fundamental feature of a cognitive system designed for the rapid learning of generalizable information.

The researchers are quick to point out that the four-second delay included in each condition of the experiment likely made it so that the infant was more likely to err. They write, "in our study, the perseverative error was reduced but did not completely disappear in the [non-communicative] and [non-social] contexts, which suggests that infants' search behavior also depends on their inhibitory, information processing, and memory skills." However, while these accounts can explain why infants might not search at the correct location, they do not explain why the infants perseverate at the wrong location. In other words, immaturity of inhibitory, information processing, or memory skills predicts random searches, rather than perseverative searches. It is specifically the perseveration of the infant at location A, then, that is due to the "pedagogical learning stance." The researchers frame this particularly elegantly:

Human infants are highly social creatures who cannot help but interpret the ostensive communicative signals directed to them. Although such a disposition prepares them to efficiently learn from adults, in certain situations (e.g., the A-not-B task) it can also misguide their performance.

The take-home message, it seems, is this: all those parents who incessantly babble at their babies in that singsongy baby-talk? That could actually a highly adaptive trait: the combination of adults' propensity towards baby-talk, combined with infants' interpretation of information provided in baby-talk as generalizable, allows infants to rapidly learn important information about their world and their culture from their caregivers.

TopÃ¡l J, Gergely G, MiklÃ³si A, Erdohegyi A, & Csibra G (2008). Infants' perseverative search errors are induced by pragmatic misinterpretation. Science (New York, N.Y.), 321 (5897), 1831-4 PMID: 18818358

Csibra, G., & Gergely, G. (2009). Natural pedagogy Trends in Cognitive Sciences, 13 (4), 148-153 DOI: 10.1016/j.tics.2009.01.005

Header image via Flickr/jeanine&preston.

jgoldman Mon, 04/25/2011 - 04:15

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Wow. That is a really clever experiment; I like the experimental designs where you have to sit back and go, hey, why didn't anyone think of doing that before?

I really wanna see the 'with and without 4 second delay' graph.

Strictly speaking, the 'inability to inhibit previously learned motor responses' isn't entirely ruled out- it would just mean that motor responses learned under social conditions get learned *differently* than motor responses learned under non-social conditions.
Which would be very cool.
All this is making me wonder if I need to reconsider the feedback I give my toddler during puzzle time. Unlike when he first got his puzzles, he almost never gets frustrated as long as I leave him alone. When I interact with him more, there are times he repeats the same (incorrect) action multiple times and gets very frustrated indeed. It could be that he's already sensitive to seeing himself as 'succeeding' in front of me (which is rather disturbing in a sense). It could be that when he does them alone, he can actually ask me for help and I might be inclined to help him, so when he would get frustrated he has a work-around. (whereas when I am sitting there watching him, I am inhibiting some desire to help him so he can do it himself, and he *knows* that *I* know he is getting frustrated and am doing nothing, and that itself is more frustrating).

I think there have also been times when I was trying to perform a motor activity that I had an audience for, and once I did it wrong I *kept* doing it wrong in the same way. I attributed this to self-defeating nervousness. And indeed, that's true in a sense. But it may be that it was this (likely innate) learning system getting hijacked as well.

very curious if you think that similar effects-- both the original A-not-B error and the social aspect-- might/do occur in dogs.

@Sam (#3): excellent question! check back on wednesday for the answer, in part 2 of this week's series of posts on pedagogy.

@becca (#2): right, the authors and I indicated that pedagogy doesn't explain everything. but lack of inhibition alone doesn't explain perseveration, specifically. as for doing the task without a short delay, the rate of success on B-trials would likely be significantly higher. the way the task is designed in the first place involves a brief delay.

Did they try it without the delay? Adult humans with known perseveration, in frontal lobe dementia for example, would be far far far less likely to perseverate after a 4 second delay.

Very interesting results though. Will be cool to see it repeated

Very interesting. Thank you!

I think we should replicate the experiment with Members of Congress.

Fascinating!

One quibble: are the findings really not consistent with the generally accepted explanations? Consider that a human adult would have an intact pedagogical learning stance, yet we would still know that an object hidden under Box B must be under Box B, yes? There must be some cognitive skill that adults possess that takes precedence over the pedagogical learning stance and allows us to perform the task correctly. Therefore, one would think that it is this skill - whatever it is - that is not yet developed in infants.

This is interesting. Their findings are consistent with the recent work done by Bonawitz. She that showed when infants and children are showed how to complete a task (in this case, where the ball is) they follow direction of the "teacher", and stop thinking as much on their own to find the ball. The teacher baby-talked to the infant in the first scenario, the infant took the teacher's direction and saw the ball was in A, so when the teacher switched it to B, the infant just went back to A, without problem-solving. The infant was already "shown the correct answer", so at that point, problem-solving ceased. Then he made the error in determining where the ball is.

In the second scenario, the teacher was present, but not giving direction, so the infant had to pay attention more and solve it on his own, thus making fewer errors. More like a hands-off approach to teaching; present, but not intrusive.

In the third scenario, the infant was basically in an independent learning state, which is consistent with Bonawitz's claim that being given too much direction with teaching inhibits independent exploration and subsequent problem-solving.

Great find, and nice analysis, Jason!

Very cool!

On the surface, this seems (to me) to be a good argument for allowing your child to play independently for periods of time, as well as parent-child interactive play. While learning quickly (ie memorization) from baby talk/parental interactions is desirable for the large amount of information babies need to absorb, independent play seems to be equally beneficial for "higher level" learning.

Experimenter's cues are facilitating the "error", but are not the cause of it. After all, "error" is not completely gone in the third setting (no experimenter).

I would actually support the view that this is not an error at all. It is just a way of learning / generalising things. E.g. at first babies learn "object is in A" rather that "object is where experimenter puts it". So they just need some more examples for learning the "correct" pattern. Which seems to lead to the original Piagetian interpretation.

It would be interesting to see statistics about how many "B examples" reverse the pattern of looking for object in A, compared to the number of initial "A examples". Also, how babies act when presented a different initial pattern, e.g. A-B-A-B-A-B. Would they look into A and B in turns or just get lost?

WOW! Thanks a lot for posting the article! I have not heard of this research before.

Besides, here you can find a paper by GyÃ¶rgy Gergely, in which he answers some criticisms on their results:

http://www.cognitionandculture.net/PedagogyWeek/pedagogy-week-the-a-not…

PsychBytes: First Names, Vegetables, and Baseball

jgoldman — Thu, 24 Feb 2011 08:30:00 +0000

PsychBytes: First Names, Vegetables, and Baseball

PsychBytes is an experiment: three recent findings in psychology, each explained in three paragraphs or less. Generally, these are papers that I wouldn't have otherwise covered in this blog. Please share your thoughts on this model in the comments. What works, and what doesn't? Would you like more PsychBytes in the future?

What's In A Name?
People who settle down and build a life in the frontier tend to be more individualistic, even if they started out with more interdependent values. Some features of the frontier life that would be attractive to an independent person are low population density, fewer social connections, and fewer social institutions. Indeed, people living in more recently settled regions in the United States more frequently behave in ways consistent with individualistic values, compared with people living in older parts of the country. This includes things like living alone after age 65 rather than moving into a retirement home, self-employment, and the getting divorced. It's possible, however, that the relationship between these individualistic behaviors and frontier life is simply a statistical accident. For example, the rate of divorce could be related to religiosity, which is in turn related to individualism. It would appear as if there was a relationship between divorce and individualistic behaviors, but it would only be due to the shared relationship with religious beliefs.

In order to address this question, Michael Varnum and Shinobu Kitayama of the University of Michigan wondered if uncommon names were more common among children born on a frontier. The way that parents choose names for their children is a well-established indicator of independent values. Varnum and Kitayama note that "naming practices embody important cultural values, and are linked to a host of psychological, social, and economic outcomes." They found that a greater percentage of babies who were born in older parts of the United States, such as New England, were given popular names (for the year the child was born), compared with babies born in newer regions, such as the Pacific Northwest and Rocky Mountains. In fact, the year in which a state was admitted to the United States was negatively correlated with the percentage of infants who were given the most popular boys' and girls' names.

Correlation between a state's inclusion in the US and the giving of top 10 names. Boys above, girls below. Click to enlarge.

And this relationship wasn't unique to the United States. A similar dataset was generated using baby names given in seven provinces in Canada: three eastern provinces which were settled earlier (Nova Scotia, Ontario, and Quebec), and four western provinces which were more recently settled (Alberta, British Columbia, Manitoba, and Saskatchewan). As expected, popular names were more common in the older provinces than in the newer provinces. A third dataset using global data further replicated these results: popular names were more common in European countries (Austria, Denmark, England, Hungary, Ireland, Norway, Scotland, Spain, and Sweden) compared with "frontier countries," founded by European immigrants (Australia, Canada, New Zealand, and the United States). Baby naming is quite a significant decision for parents. It makes sense, then, that the practice would reflect cultural values.

Varnum ME, & Kitayama S (2011). What's in a Name?: Popular Names Are Less Common on Frontiers. Psychological science : a journal of the American Psychological Society / APS, 22 (2), 176-83 PMID: 21196534

Vegetables for Fun and Profit
How often do you hear parents promising their children dessert upon completion of their vegetables? While this sort of external motivation is very powerful, there is a potential downside: it could undermine intrinsic motivation. In other words, children might simply eat the vegetables to get the reward, and therefore never grow to like the vegetables themselves. This could result in poor eating choices later in childhood and adolescence, when the child is free to make his or her own decisions. The scientific literature on the use of incentives for children's vegetable consumption shows mixed conclusions: some studies show that vegetable intake increases when paired with a reward, and that those increases are maintained when the reward is withdrawn. Other studies find that as soon as the rewards are removed, vegetable intake returns to baseline. Lucy J. Cooke and colleagues from University College London and the University of Sussex attempted to clarify this confusing picture.

Over the course of twelve days, children age 4-6 were exposed to a vegetable they didn't like. The children were divided into three intervention conditions and one control condition. In the first intervention condition, vegetables were paired with non-edible rewards such as stickers. The second intervention condition paired social rewards (praise) with vegetables. The third intervention condition included no external reward; could exposure alone could increase liking for a previously disliked vegetable? Finally, the children in the control condition received no vegetables and no rewards.

The kids in all three intervention conditions reported increased liking for their disliked vegetable after twelve days, with no significant differences between the three conditions. The liking was maintained for three months for the two reward conditions, but not for the exposure-only/no-reward condition. Taken together, this experiment suggests that rewarding children for eating their vegetables is not only extremely effective, but lasts a considerable amount of time following withdrawal of the reward. In fact, exposure alone without a reward is actually less effective. Parents: keep that dessert coming!

Cooke LJ, Chambers LC, AÃ±ez EV, Croker HA, Boniface D, Yeomans MR, & Wardle J (2011). Eating for Pleasure or Profit: The Effect of Incentives on Children's Enjoyment of Vegetables. Psychological science : a journal of the American Psychological Society / APS, 22 (2), 190-6 PMID: 21191095
Photo: Flickr/woodleywonderworks

How Do We Set Personal Goals?
Why are students who score 89% on an exam more likely to study harder before the subsequent exam, compared with students who score 82%? In both cases, the scores are just one percentage-point below the next grade level: 90% would be an A-, while 83% would be a solid B. And the amount of extra effort necessary to achieve a higher grade for either student is roughly equivalent. Devin Pope and Uri Simonsohn from the schools of business at the Universities of Chicago and Pennsylvania, respectively, think that round numbers serve as "cognitive reference points," which people use when judging their own outcomes. In other words, individuals whose performance is just short of a round number (such as our B+ student) would be more likely to work at improving their performance, compared with people whose performance is just above a round number (such as our B- student). To test this prediction, Pope and Simonsohn collected data from professional baseball players and high school students taking the SAT exam.

The data matched with their predictions. Professional batters were four times more likely to end a season with a .300 batting average than with a .299 average. High school juniors were 10-20% more likely to re-take the SAT in an effort to boost their scores if their initial score ended in "90" (as in 1190 or 1290) than if their initial score was just ten points higher (1200 or 1300). Real life implications of this research are clear; round number reference points often matter for real-life decisions. If you've lost 29 pounds, you might be motivated to make it an even 30. If you've run 18 laps, you might complete two more, even if you're tired. If you've written 8 pages of your term paper, you might keep working until you've written 10.

Pope D, & Simonsohn U (2011). Round numbers as goals: evidence from baseball, SAT takers, and the lab. Psychological science : a journal of the American Psychological Society / APS, 22 (1), 71-9 PMID: 21148460

jgoldman Thu, 02/24/2011 - 03:30

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What Is Psychopathology? Examining the Changing Status of ADHD

jgoldman — Fri, 05 Nov 2010 09:00:00 +0000

What Is Psychopathology? Examining the Changing Status of ADHD

Despite the fact that my research lies at the intersection between cognitive, comparative, and developmental psychology, I am also quite interested in the evolution of our understanding of psychopathology. The ultimate goal of the study of psychopathology is to ground such disorders in brain and body. But our understanding of some pathologies are simply not there yet (though some of our therapeutic interventions still prove effective even if we don't quite understand the etiology of a given disease or disorder). The main conflict in the field that characterizes the study of psychopathology is regarding the nature of psychopathology itself. Do psychological disorders reflect disease states superimposed onto otherwise healthy individuals? Or are psychological disorders wrapped up in personality and fundamental to the organization of a person? And to what extent does culture determine the extent to which we pathologize certain behaviors?

Complicated questions indeed. Consider the case of ADHD as a case study in the evolution of psychopathology.

What is ADHD? Paradigm Shifts in Psychopathology
Portions of this essay originally posted at Child's Play

Over the last one hundred years, paradigm shifts in the study of psychopathology have altered our conceptualization of attention deficit/hyperactivity disorder (ADHD), as a construct and as a diagnostic category. With few exceptions, it has generally been accepted that there is a brain-based neurological cause for the set of behaviors associated with ADHD. However, as technology has progressed and our understanding of the brain and central nervous system has improved, the nature of the neurological etiology for ADHD has changed dramatically. The diagnostic category itself has also undergone many changes as the field of psychopathology has changed.

In the 1920s, a disorder referred to as minimal brain dysfunction described the symptoms now associated with ADHD. Researchers thought that encephalitis caused some subtle neurological deficit that could not be medically detected. Encephalitis is an acute inflammation of the brain that can be caused by a bacterial infection, or as a complication of another disease such as rabies, syphilis, or lyme disease. Indeed, children presented in hospitals during an outbreak of encephalitis in the United States in 1917-1918 with a set of symptoms that would now be described within the construct of ADHD.

In the 1950s and 1960s, new descriptions of ADHD emerged due to the split between the neo-Kraepelinian biological psychiatrists and the Freudian psychodynamic theorists. The term hyperkinetic impulse disorder, used in the medical literature, referred to the impulsive behaviors associated with ADHD. At the same time, the Freudian psychodynamic researchers (who seem to have won the battle in the DSM-II) described a hyperkinetic reaction of childhood, in which unresolved childhood conflicts manifested in disruptive behavior. The term "hyperkinetic," which appears in both diagnoses, describes the set of behaviors that would later be known as hyperactive - despite the fact that medical and psychological professionals were aware that there were many children who presented without hyperactivity. In either case, it was the presenting behavior that was the focus - which was implicit, given the behavioral paradigm that guided the field.

When the cognitive paradigm became dominant, inattention became the focus of ADHD, and disorder was renamed attention deficit disorder (ADD). Two subtypes would later appear in the literature, which correspond to ADD with or without hyperactivity. The diagnostic nomenclature reflects the notion that the primary problem was an attentional (and thus, cognitive) one and not primarily behavioral. The attentional problems had to do with the ability to shift attention from one stimulus to another (something that Jonah Lehrer has called an attention-allocation disorder, since it isn't really a deficit of attention). The hyperactivity symptoms were also reformulated as cognitive: connected with an executive processing deficit termed "freedom from distractibility."

In DSM-IV, published in 1994, the subtypes were made standard and there wasn't much change in the diagnostic criteria per se, but there were changes in the name of the disorder, which reflected changes in the literature in terms of the understanding of the etiology of the disorder. The term ADD did not hold up, and the disorder became known as ADHD, with three subtypes: ADHD with hyperactivity/impulsiveness, ADHD with inattention, and a combined subtype in which patients have both hyperactive and attention-related symptoms. Due to improved neuroimaging technology, these subtypes seem to reflect structural and functional abnormalities found in the frontal lobe, and in its connections with the basal ganglia and cerebellum.

The set of the symptoms associated with ADHD seem not to have changed much in the last one hundred years. However, paradigm shifts within the field of psychopathology have changed the way in which researchers understand the underlying causal factors, as well as which of the symptoms are thought to be primary.

Developmental Continuity in ADHD
Is there such a thing as adult ADHD?

In the DSM-IV-TR (and earlier versions of the DSM as well), attention deficit hyperactivity disorder (ADHD) falls under the superordinate category "Disorders First Appearing in Infancy, Childhood, or Adolescence." Until the early part of the twenty-first century, many researchers and clinicians (and certainly the public) thought that children grew out of ADHD, and there was no adult variant. Some researchers have started to argue that there is, indeed, an adult variant of ADHD, and there is continuity in the disorder across development.

A key issue in the diagnosis of adult ADHD is the fear that adults could claim to suffer from the disorder as an excuse for otherwise unacceptable behavior. Connected to this is the fear among the general public that the pharmaceutical industry created the label 'ADHD' for kids who are simply disrespectful (think: Bart Simpson) or otherwise act inappropriately. However, in their well-regarded position paper, Barkley and colleagues described ADHD as a real disease-like state, and maintained that it was biologically defined and heritable.

The symptom profile for ADHD includes deficits in emotional regulation, irritability, peer rejection, and academic difficulties. Barkley describes a biological etiology for ADHD involving a heritable frontal lobe disorder that stays with an individual throughout development. What changes, then, must be are the symptoms associated with the underlying cause.

The main problem is that the diagnostic criteria for ADHD are normed for children, not for adults. The problem runs a bit deeper, however. ADHD has been conceptualized as a developmental disorder, which means that a pathological individual's behavior must be inappropriate relative to his or her peers - and that behavior must somehow cause impairment in major life activities. This conceptualization assumes that individuals with a developmental disorder are merely behind their peers in the development of normal psychological traits, and not mal-developed. In order to define adult ADHD, diagnostic criteria must be used relative to other adults - this set of symptoms does not exist yet in the DSM. A complication is that the frequency of ADHD symptoms tends to decline with age. Unless the diagnostic criteria acknowledge this (and they don't), then the number of individuals who fit within the diagnostic category with decrease through development.

Another piece of evidence for the developmental continuity of ADHD into adulthood comes from a 2002 study by Barkley, Fischer, Smallish, and Fletcher. Their thirteen-year longitudinal study found a low frequency of self-reported ADHD by the individuals themselves upon reaching adulthood. However, a far higher frequency was found when using parent reports (completed by parents of adult children). Not only were the parent reports more reliable, but they were also more valid: they were more strongly and pervasively associated with adversity in major life activities than were self-reports.

Taken together, the etiological continuity proposed by Barkley, the lack of sufficient norms for adult diagnosis of ADHD, and the psychometric continuity in parent reports, all point at least to the plausibility - if not the real existence - of adult ADHD as a valid diagnostic category, and therefore developmental continuity in the disorder.

Note: this post is part of a mini-carnival on the topic of psychopathology and mental illness. Check out all the other blogs that are participating!

Barkley, R. (2002). International Consensus Statement On ADHD Journal of the American Academy of Child & Adolescent Psychiatry, 41 (12) DOI: 10.1097/00004583-200212000-00001

Barkley RA, Fischer M, Smallish L, & Fletcher K (2002). The persistence of attention-deficit/hyperactivity disorder into young adulthood as a function of reporting source and definition of disorder. Journal of abnormal psychology, 111 (2), 279-89 PMID: 12003449

Image source.

jgoldman Fri, 11/05/2010 - 05:00

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JG > May the Wind be at your Back in your ADHD Solution Quest.

Something as simple as relearning to crawl could diminish or eliminate hyperactivity in children, a researcher claims.

Nancy O'Dell, a professor of child development, blames the behavior on symmetric tonic neck reflex, a normal response in infants to assume the crawl position by extending the arms and bending the knees when the head and neck are extended,

She said it disappears when neurological and muscular development allows independent limb movement for actual crawling but can cause issues later in childhood if not addressed.

"If they don't crawl enough or properly, this reflex is going to make it really hard for them to sit still in school, really hard for them to write and really hard to pay attention," O'Dell said. "It's the same behavior as ADHD."

June 14, 2010 (San Antonio, Texas) â A new study shows that sleep problems in children correlate strongly with symptoms that mimic those of attention-deficit/hyperactivity disorder (ADHD). The findings were presented here SLEEP 2010

Oh, boy. So, so many comments to make on this topic... where to start...

First, GREAT article, Jason. This is one of my personal fave topics of discussion in psychopathology, and one of the most misunderstood and abused ones by the general public.

I will come back and comment further, but for now, I'll say that in regards to developmental continuity, it's a complex and multi-faceted issue. Developmentally speaking, yes, ADHD kids have a less-developed PFC than controls. And yes, that developmental gap closes as they reach adulthoodâthe gray matter volume catches up with controls after adolescence so the "developmental gap" is no longer there, in that respect (see Shaw, et al for his work on plasticity & intelligence in childhood).

However, there is a lot more to ADHD than lagging development of the PFC. Also, once that gap closes, all of the other features are still thereâ their brain (specifically PFC)is just more developedâtherefore more control over behavior (the "hyperactivity", if present, may subside). It is because of this that people think "kids outgrow" ADHD. Simply not the case.

Kids may gain more control over their outward displays of behavior, but their predominant thinking patterns are still thereâinflux of info coming at an increased rate, availability of DA receptors, etc. ADHD is also highly correlated w/ intelligence and creativity (both present), which tells me there is a lot more going on than people thought 100 years ago.

One final thought for now: the differentiation of adult ADHD is a load of crap. If you look at what ADHD actually is (lack of focus, not attention per se, also pointed out by J. Lehrer)then there would be less need for the distinction in definition of childhood/adulthood disorder.

So... superb article. Loved it!

As many of my friends begin menopause, we are finding something new in our experience. We are familiar with ADHD through our children or friends of our children. And we are not choosing hormone replacement therapy. And we seem to be losing our minds. We are distracted, can't concentrate on one thing, jumping out of our skins. Now some of these friends are trying ADHD meds, like Ritalin, Concerta, Strattera - and are finding that the symptoms that came on with the loss of our natural hormones are going away. I'm not sure that there has been any research on whether hormone changes can cause cognitive changes that are basically late-onset ADHD, which can be treated successfully with ADHD meds. Though these symptoms don't seem to come from a lack of deveopment in a particular lobe, it is interested that they mimic classic ADHD symptoms and can be treated the same way. Now that HRT is less common, I think that women who have access to medical care and are familiar with ADHD are going to press for more research into this area.

This is a great introductory article, Jason. I think that you missed another of the key points that impedes the development of the adult ADHD diagnostic criteria though: drug abuse.

As an adult who lives with ADHD and as someone actively involved in the ADHD advocacy community, I see this issue raised time and time again. Certain members of the public and some doctors believe that adults seeking an ADHD diagnosis do so to gain access to stimulant medication for performance enhancement reasons.

Although medication is usually the first port of call in ADHD management, there is much more to it than that (CBT, time management training, career advice etc...) We urgently need an adult ADHD diagnosis so that those struggling to cope with everyday life can receive the support that will help them so much and it's a real shame that people's fixation on the medication aspect slows down the already - rightly so - slow progress of science.

Speaking as someone diagnosed ADHD as a child, I find that I have no trouble believing in adult ADHD and have difficulty understanding how it's even a question. I'm as attention "deficit" as I ever was. The only difference is that, as an adult, I have a lifetime of experience dealing with the issues and built up coping skills that the child me could not have when he was diagnosed. I am, essentially, just better at dealing with the challenges of being me.

You explained that more ADHD cases have been noticed by parents in relation to their children. Do you think the reason for that is because parents sometimes worry a bit too much about their children or that other people tend to notice ADHD in a person. Is it specifically a parent that notices it or could it be a good friend?

Nice piece. Thank you.

Barkley and colleagues proposed a new set of criteria for Adult ADHD (for upcoming DSM revision), based on the research outlined in their book "Adult ADHD: What the Science Says."

I don't know the status of DSM deliberations, but it will be a shame if this criteria is not adopted. I found it so useful and important that I included it in my book (a guide to understanding and treating Adult ADHD) so that readers could have access to it.

You write:
"A key issue in the diagnosis of adult ADHD is the fear that adults could claim to suffer from the disorder as an excuse for otherwise unacceptable behavior."

I'm not sure who has that fear -- perhaps people who don't understand ADHD? As someone else mentioned, sure medication "diversion" is an issue, especially in younger populations.

But in my long experience as an ADHD advocate and, more recently, author and international speaker on ADHD, the larger problem is the "denial" around ADHD among clinicians, the public, and especially people with undiagnosed ADHD.

Gina Pera, author
Is It You, Me, or Adult A.D.D.?

to Momof2,

You bring up a very important topic: ADHD in women and HRT.

Cynthia Gorney wrote an interesting piece in the NYTimes Magazine a few months ago about women turning to estrogen for mid-life cognitive issues. I was disturbed to see nary a mention of the possibility of ADHD and its more benign treatment (stimulant medications).

ADHD experts such as Dr. Patricia Quinn have long acknowledged the role that fluctuating hormones plays in managing ADHD. Even young women might need a higher dose of the stimulant at certain points in their menstrual cycles. And certainly many women in perimenopause first realize they have ADHD when their hormonal changes leave them with fewer compensatory strategies for dealing with lifelong ADHD symptoms. They can literally feel as though they "hit the wall."

Precisely the situation writer Gorney described as her personal experience. But only mention of estrogen, no mention of how neurotransmitters are affected by hormonal precursors, pushing women with unrecognized ADHD into more extreme symptoms. What a shame.

@Gina - Thanks for your reply to my comment. A couple more thoughts: it's important for periomenopausal women to have their thyroids checked first, because changes in thyroid function can present some of the same symptoms. Though the party line to women seems to be "if you first notice ADHD symptoms with menopause, you had ADHD all along and didn't know it." I think this ignores that fact that ADHD-like symptoms can be caused by the effect of hormones on neurotransmitters, and that this may be the first onset of ADHD-like symptoms. And if the ADHD-like symptoms respond to all of the classic ADHD medications, then I for one am going to say that this is not ADHD-like, it is actually ADHD. I think that there is such a commitment to the notion that there cannot be any adult-onset ADHD, that any evidence to the contrary is simply ignored. "Oh, you had ADHD before - you just don't know what you are talking about, sweetie."

Re: the menopause and ADHD thing. Girls are much less likely to be diagnosed with ADD than boys, and those old enough to be hitting menopause went through childhood before it was commonly diagnosed. I'm 40, and I've long suspected I have ADD, but it didn't show in school because I got good grades in spite of constantly losing papers. Learning seems to put me into hyperfocus mode if the material is presented at all well.
Anyhow, maybe the women *and* the doctors are right? It would be interesting to find out if something in female hormones downplays some ADD/ADHD issues. If a masking or compensating factor is taken away, an underlying condition may seem new without being truly new.

* Psychiatrists come up with conditions like "Attention Deficit Hyperactivity Disorder Without Hyperactivity" (which clinically make up a large share of all ADHD cases) and then wonder why people think they're weird.

* Date of onset is a useful diagnostic tool for a variety in mental conditions, with increasing evidence supporting the idea that most anxiety disorders are among those "First Appearing in Infancy, Childhood, or Adolescence." But, it is less obvious that this is a useful classification scheme as Adult ADHD seems to be validated as a construct, particularly with respect to the non-hyperactivity part.

* I'm surprised that the "Paradigm Shifts" article doesn't take the one extra step of considering the evolving notion of "neurodiversity," i.e. that some neurological conditions are different without necessarily being pathological in all circumstances (something implicit in an "impairment in major life activities" part of the diagnosis).

There is a defensible case that "hyper-focus," a strong desire to get out of ruts, and an ability to connect distant concepts associated with ADHD can have adaptive value in the right contexts.

A neurodiversity view doesn't necessarily deny that a neurological condition can be problematic in some contexts or that professional help in coping with it can't be useful. But, it doesn't automatically pathologize something that is part of the person's biologically determined fundamental psychological makeup.

* The progress on understanding whether ADHD is really a single disorder, or instead a cluster of disorders that present similarly and may be co-morbid, is disappointingly slow. So too has indifferent progress towards determining whether traits like "novelty seeking" and "low conscientiousness" in the Big Five personality traits are really part of the same underlying syndrome or are distinct. Is there a continuum or a distinct disorder?

* It is also a little disappointing that psychiatry hasn't staked out a middle ground between people who have a disorder that must be treated because it produces "impairment in major life activities" and people who have no impairment at all. Is there not room for a category of people who benefit from medication or treatment activity, even if they manage to cope adequately with "major life activities" by some means or another?

First of all, Jason, your post is thorough and amazingly informative to those of us less involved in psychopathology. I know several people who I have often thought might have ADHD. However, I was not sure if they actually had a diagnosable disease that would make them behave poorly and require special treatment, or if they were merely rambunctious. Even if, as you say, there are brain malformations responsible for ADHD, is it not possible that such formations in fact occur to a lesser degree in all people? I am wondering whether this is truly a disease that one can either have or not have and would require special help with, or whether it is merely a particularly hyperactive state of being with which one can successfully cope alone.

I get really bloody irritable with this idea of adult ADHD being an excuse for bad behavior. I spent my entire childhood being told (including by my dad) that I didn't have atypical neurology (not quite in those terms), that I was just lazy and just needed a good kick in the butt - ignoring the fact that the belt my dad regularly employed on said butt didn't change a thing. I was told that ADD was just a big crock enough times and with enough vehemence, that I started to believe I was just lazy and if only I tried harder, everything would be fine.

While that is not entirely responsible for my dropping out of school and into nearly two decades of varying degrees of substance abuse, it certainly played a strong role in it. That, of course, being coupled with a neurological disorder that can be partly defined by dopamine deficiencies - something that can be a driving force behind addictions and substance abuse.

And now we want to play this same game with adults. I am working very hard to moderate my language, but were I not commenting where I am, I would be using language that would make paint curl. I am over people deciding that because they don't understand something - or because it is just too complicated, that it mustn't exist. That it is just as excuse.

I engaged in a great many negative behaviors, some of which I am honestly sorry about and many others, I am absolutely not. I wasn't engaging in healthy behaviors, but I was mostly just screwing myself up. I don't use my neurological issues as an excuse for my behavior, because there is very little I actually regret about it. What I was able to do when I was seeing a therapist last year, was to look objectively at my life as a substance abuser and realize that my behaviors weren't behaviors generally associated with people who aren't rather seriously screwed up.

That I accept that my neurological problems were strong driving factors in my behavior, doing so is not making an excuse for it. It is helping me understand it and better understand what is going on, when I really want to take some acid, or get completely wasted in some other way. It also helps me understand what I might need to discuss and how I will discuss substance related issues with my eldest, who could be the poster child for attention deficit issues, combined with major depression (the latter being situational, probably leading to chemical).

The bottom line - there is absolutely no question whatever, that I have severe ADHD. I don't just fit the criteria a little bit - I fit it to a T.

ohwilleke -

ADHD without hyperactivity is something of a misnomer. I have ADHD without hyperactivity. The problem is that I am extremely hyperactive - just not so that most people would notice. About the only outword manifestations are the occasions when I vibrate (not noticeable from any distance) and when I am getting manic - the latter having little to do with ADHD, at least in theory.

What I do experience is a brain that simply won't stop - ever. Before going on meds, I was constantly thinking about four to eight things at a given moment. Not several things that I was thinking about in rapid succession, things that I was thinking about at exactly the same time - or if I was going in succession, it was rapid enough that the distinction is pointless.

Going manic is something altogether different but related, because that is what first got me labeled with ADHD. Becoming manic was also really a drag for me, because I was high-energy, but still depressed. I was also entirely unable to focus. And while the drugs help, it is still difficult, as I seem completely incapable of cleaning one thing at a time. Cleaning the kitchen is the worst, because I end up wandering to get something and then notice a brilliant distraction.

Only now, on drugs, I don't experience it several times a day, absolutely everyday.

There seems to be a trend to label kids, especially boys as ADHD and just put them on medication. Boys tend to be disruptive, inattentive and hyperactive-this is what boys do. Trying to get the boy out of boys is ludicrous - should we perhaps try to turn them all in to little girls?

Like all medicines, there must be some trade off at the end of the day with physiological effects from Ritalin etc somewhere else in the system. Most abnormal behavioral traits have some distinct advantage to the "sufferer" in some niche within our very diverse socoiety. Do we all want to be monotone drones that some entity has decreed us all to be ?

The trend to diagnose ordinary "boyish" behavior as some disease state is a fad. The doling out of medicines to a generation of boys could leave the legacy of a "lost" generation but rich drug companies.

I was finally diagnosed at 40. Prior to diagnosis, my condition was treated with punishment, scolding, rejection, and general social disapproval. Post-medication, my life is less chaotic and I often go weeks without being yelled at. I wish someone had noticed years ago that my problem wasn't some moral failure on my part before half of my life was gone, my soul sucked away by criticism, and many doors shut in my face. I don't feel dronish in the least, but even if I did, it's better than feeling like a failure. So parents who desperately want to believe that "they're just being boys" or "I don't want a cookie cutter kid", go ahead and believe what you may. But if I had the option of medication as a kid, I think that my life would have turned out better.

Of course there is adult ADHD. When my son was diagnosed with it and I found out that there was a familial component to this disorder, I suddenly realized that both my mother and my brother have it, as do at least two of my cousins. In some ways, having ADHD without the hyperactive component, as my son, my mother and my brother do, means that your problems with coping with life sort of fly under the radar, even if they still mess you up in various ways. All three of these people are intelligent and productive members of society, but it has cost them. Things involving focus that are not a problem for nonADHD'ers are a major effort for them. The fact that they make this effort is a tribute to their determination, will, and hard-won coping skills.

I do not appreciate Jim Sternhall's comments; my son was never a discipline problem, ADHD is not just a fad. There are neurological differences, which can be seen in a brain scan. ADHD medications can make the struggle to focus easier, so why not take them? What is it about psychiatric disorders that means that even though there is medication to help, taking it makes you a bad or weak person? Nobody thinks you should just tough out heart disease or asthma; why should ADHD or depression be any different?

The problem with all these psych drugs and those who take them, is that accepting them as valid solutions to valid problems, requires people to accept that being human is complicated and one of the potential complications is psychopathology. Worse, psychopathologies are exceedingly complicated in their own right, because we don't really understand a whole lot about a lot of them - and you can't "see" the effects of them, the same way you can, say, cancer or heart disease.

So rather than try to understand or even consider a world beyond a narrow crevasse, as far too many people do, it is much easier to perpetuate harmful stigmas. Because who wants to spend the time and energy and possible mild discomfort at the thought of what many people have to deal with every bloody day, when it is much easier to perpetuate ideas that make people ashamed of who and what they are, about how their brain works and push them to keep beating their head against the wall, just trying to force themselves to make it all work (in case you're wondering, this rarely works, often makes things much worse, because when people fail, they feel worse about themselves).

But lets not knock on Jim, because that might make him uncomfortable and we wouldn't want that.

Ed Tronick and the "Still Face Experiment"

jgoldman — Mon, 18 Oct 2010 08:30:00 +0000

Ed Tronick and the "Still Face Experiment"

In 1975, Edward Tronick and colleagues first presented the "still face experiment" to colleagues at the biennial meeting of the Society for Research in Child Development. He described a phenomenon in which an infant, after three minutes of "interaction" with a non-responsive expressionless mother, "rapidly sobers and grows wary. He makes repeated attempts to get the interaction into its usual reciprocal pattern. When these attempts fail, the infant withdraws [and] orients his face and body away from his mother with a withdrawn, hopeless facial expression." It remains one of the most replicated findings in developmental psychology.

Once the phenomenon had been thoroughly tested and replicated, it became a standard method for testing hypotheses about person perception, communication differences as a result of gender or cultural differences, individual differences in attachment style, and the effects of maternal depression on infants. The still-face experiment has also been used to investigate cross-cultural differences, deaf infants, infants with Down syndrome, cocaine-exposed infants, autistic children, and children of parents with various psychopathologies, especially depression.

Why has this experiment, first published in the mid-1970s, become so important?

The still face experiment demonstrated that very young infants already have several basic building blocks of social cognition in place. It suggested that they have some sense of the relationship between facial expression and emotion, that they have some primitive social understanding, and that they are able to regulate their own affect and attention to some extent. The infants' attempts to re-engage with their caregivers also suggest that they are able to plan and execute simple goal-directed behaviors.

In addition, the still face experiment is among the more reliable and valid measurements of infant cognition and behavior; infants find it more disturbing than other violations of normal social interactions (such as the Ainsworth Strange Situation). The response is very complex, with infants displaying subtle facial cues such as dampened smiles, yawns, and sideways glances at the mother. Further, and perhaps most importantly, the still face experiment was the most revealing experiment conducted in terms of infant social cognition. By 1975, researchers had already devised ways to describe and quantify the reciprocal social exchanges that are characteristic of infants and their caregivers. However, the still face experiment allowed researchers to examine the ways in which infants spontaneously initiate social exchanges and the way they modulate their affect and attention, and provides rich data on the ways in which infants re-organize their behavior after the re-establishment of the reciprocal interaction. Importantly, it is a very easy experiment for researchers and parents to properly execute, which is perhaps why it is so popular.

The still face experiment has also proved useful in determining the extent of an infant's social world. That is, the still face effect is not only elicited by the mother (i.e. the primary caregiver), but also by fathers, strangers, and even by televised images of other adults. However, infants do not respond in similar ways to objects, no matter how interesting, interactive, or dynamic they appear to be. This provides more evidence that young infants readily categorize the world into potential social partners and inanimate objects.

The still-face experiment has likewise been useful in answering questions about how the still face effect may be related to earlier experiences and how it may predict later social-emotional variables. For example, variations in the still-face effect have been associated with mothers' baseline sensitivity and interactive style, and the infants' later attachment classification at age 1, internalizing (e.g. depression, anxiety) and externalizing (e.g. aggression, impulsivity) behaviors at 18 months, and behavior problems at age 3.

For an experiment that is so useful, so robust, so popular, one might think that it has outlived its usefulness, at least as far as research is concerned. But despite the robustness of the effect, nobody has been able to fully explain it. No theoretical paradigm has been able to account for the infants' response. Therefore, it is an area open for more investigation.

Adamson, L., & Frick, J. (2003). The Still Face: A History of a Shared Experimental Paradigm Infancy, 4 (4), 451-473 DOI: 10.1207/S15327078IN0404_01

Tronick, E., Adamson, L.B., Als, H., & Brazelton, T.B. (1975, April). Infant emotions in normal and pertubated interactions. Paper presented at the biennial meeting of the Society for Research in Child Development, Denver, CO.

Image from Daily Mail

jgoldman Mon, 10/18/2010 - 04:30

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This I think explains what happens when Mom is engaged with her baby, then her cell phone rings, and quickly the baby gets 'fussy'. Mom's phone face is utterly uncorrelated with the baby's efforts to connect.

OK, I just tried it on Huxley. Instead of going cold, he started giggling and dancing, then he filled his diaper.

BTW, FWIW, Ed was one of the principles on the Ituri Forest project so we are distant colleagues (though I only worked with his grad students, and I'm not entirely sure what they were doing).

Oooh, interesting (@Greg). I bet if you did it longer, he would've stopped the giggling and dancing. But the fact he filled his diaper is totally in line with the predictions, in terms of losing self-control (loss of muscle tone, drooling, etc).

This sounds like the meanest experimental procedure ever! (Except perhaps the marshmallow test.) I think that, even if the still-face response is ever explained, it will probably still be a useful test, and might even become a diagnostic tool.

BTW, don't forget to submit something to Encephalon this month! I'm taking submissions until the 29th.

It's possible I was making a silly face instead of the proper experimental face.

I found it very interesting that infants are able to perceive a loss of interaction and express negative emotions at this lack of engagement. The connection to the mother was astounding. The common misconception that babies are oblivious and donât engage in the world is proven false with this experiment. Even without verbal communication, the infant was able to express its discomfort and stress. It is also fascinating how such a basic experiment is used to study the intricacies of infant psychology. I never would have imagined that such a simple interaction could predict future emotions. However, I wonder if the baby was upset with the mother ignoring her or upset that she had no one to play with, and was in essence alone.

I found the still-face experiment very interesting, because it showed how much influence parents could have on their child. Before I read this article, I never thought that infants were able to interact with their mother by displaying facial expressions such as dampened smiles, yawns, and sideways glances at the mother. In the video, during the still-face experiment, the baby made repeated attempts to get the interaction into its usual pattern. When these attempts failed, the infant withdrew his face and body away from his mother with a hopeless facial expression. Therefore, I believe that the interaction between a mother and her child is very important. If a baby begins to feel hopeless about the relationship between his/her mother, it could have many negative impacts on the baby while living out in the future society.

Wow, this is truly fascinating. I never thought babiesâ brains would be developed enough for having interactions with others. But clearly, they are able to connect with their mothers, even trying to gain their mothersâ attention by performing a variety of actions. They knew what to do because of the usual patterns they engaged in, giving clues of long-term memory forming already. Also, itâs amazing how the prediction of later emotion and sociability could be based on the results of this experiment. Overall, I think it tells us how important it is for the parents to care for the baby.

Could this perhaps be useful as a screening test for autism?

I think this is very interesting because we usually think of babies as unintelligent and that they donât really understand anything thatâs happening around them. But this experiment really shows that infants are highly intellectual by being able to pick up on emotional responses. In the video, the baby almost instantly recognized that something was wrong with her mother, and therefore responded with negative reactions. This illustrates that a mother has an enormous effect on her child through her expression, so imagine how much of an effect she has on the child through other aspects like movement and voice. I find this astounding that at such a young age, a human is intelligent enough to know the difference between the usual state of his or her mother and the abnormal state. If this experiment showed results in a matter of minutes, how would this affect the child if a mother was non-responsive for years?

Wowâ¦ I was amazed at how much the babyâs emotions change over such a short period because of a mother not reacting. This just comes to prove that babies do have real emotions, and the things they experience will have an effect later on in their life. I mean, even I would feel very lonely and upset if a friend just suddenly didnât react to what I was saying or doing. But I felt that reading this article really opened my eyes, because I havenât been that responsive to infants, say, when we go to group parties and the teenage kids are in charge to take care of the little ones. This also I believe will be useful information for me when I get older and start a family of my ownâ¦ Never ignore your baby completely, or for a long period of time.

I thought about this scenario with a child with autism in mind. Imagine if instead of the mother being "stillfaced" it was the child! Imagine if the mother was attempting, as the baby in the clip was, to engage the baby and the baby was non-responsive! How must that feel to a parent of that child! They must be desperate to get that interaction from the little one that they love so much!

I can see how a parent of a child with autism would do just about anything to have this typical interactive dance with their child! I can't imagine how I would feel if my son couldn't engage with me in this way!

This study really hits home for me in the work I am doing with families with children on the spectrum using RDI to restore this foundational relationship, as I can really see how without this relationship intact, all developmental milestones would be affected!

But the fact he filled his diaper is totally in line with the predictions, in terms of losing self-control. I wonder if the baby was upset with the mother ignoring her or upset that she had no one to play with, and was in essence alone.

They knew what to do because of the usual patterns they engaged in, giving clues of long-term memory forming already. Also, itâs amazing how the prediction of later emotion and sociability could be based on the results of this experiment.

Children and Their Pets

jgoldman — Mon, 27 Sep 2010 08:30:00 +0000

Children and Their Pets

Your humble narrator finds himself sick with a cold, so here's a post from the archives.

There is considerable research on how children interact with other children and with adults, and how child development can be influenced by those interactions. But research on children's interactions with non-human animals seem to be limited. Given how ubiquitous pets are in the homes of children (at least, in WEIRD cultures), it is somewhat surprising that there hasn't been more work on the way pet ownership might affect child development.

According to the US Humane Society:

There are approximately 77.5 million owned dogs in the United States
Thirty-nine percent of U.S. households own at least one dog
Most owners (67 percent) own one dog
Twenty-four percent of owners own two dogs
Nine percent of owners own three or more dogs
On average, dog owners spent $225 on veterinary visits (vaccine, well visits) annually

There are approximately 93.6 million owned cats in the United States
Thirty-three percent of U.S. households (or 38.2 million) own at least one cat
Fifty-six percent of owners own more than one cat
On average, owners have two cats (2.45)
Cat owners spent an average of $203 on routine veterinary visits

Developmental scientist Gail F. Melson noted this paucity in research in a 2003 review paper in The American Behavioral Scientist. Melson points out that most parents report that they acquired their family pets "for the children," and given the ubiquity of child-pet bonding and interaction, she suggests that it is an important area for child development research to investigate. She goes through several topic areas in child development and examines what has been learned, or could be learned, by investigating human-animal bonding.

Perceptual and Cognitive Development

Melson starts with Eleanor Gibson's work on perceptual development, and in particular, her theory of perceptual affordances - that is, infants extract knowledge from the world by interacting with the world; by looking at, hearing, feelings, tasting, and acting on objects, and discovering what objects "afford" - the "what can I do with this" for each object.

Babies can readily differentiate pet dogs and cats from "life-like" battery-operated toy dogs and cats. Babies will smile at, hold, follow, and make sounds in response to the live animals more than in response to the toys. In one study, 9 month olds were more interested in a live rabbit than an adult female stranger or a wooden turtle. A 1989 study of 2- to 6-year-olds with animals in their classrooms showed that children ignored realistic stuffed animals (80% never looked at them), but that live animals - especially dogs and birds - captured the attention of the children. Seventy-four percent touched the dog, 21% kissed the dog, and more than 66% talked to the bird.

Living with pets seems to stimulate children's learning about basic biology. In one study, Japanese researchers showed that kindergarteners who had cared for pet goldfish better understood unobservable biological traits of their goldfish, and gave more accurate answers to questions like "does a goldfish have a heart?" They also showed better reasoning about other species by using analogies: one child inferred that a baby frog "will grow bigger, much as the goldfish got bigger."

Though there haven't been any studies, Melson hypothesizes that caring for animals may also give children more elaborated and accurate ideas about life and death.

Finally, Melson points out that animals present good learning opportunities for the simple reason that children learn and retain more when they are emotionally invested, and that children's learning is optimized when it occurs within the context of meaningful relationships. There is no reason that the only meaningful relationships for young children should be human relationships.

Social and Emotional Development

When asked to name the 10 most important individuals in their lives, 7- and 10-year-olds on average included 2 pets. Melson offers two important functions of companion animals that might support social/emotional development.

The first is social support. Dozens, if not hundreds, of studies demonstrate that lack of human social support is a risk factor for physical and psychological problems, especially for children, and there is evidence that pet-owning children derive such emotional support from their pets. A 1985 study of 7- and 10-year-olds in California showed that pet owners were equally likely to talk to their pets about sad, angry, happy, and secret experiences as with their human siblings. Seventy-five percent of Michigan 10- to 14-year-olds reported that when upset, they turned to their pets. Forty-two percent of Indiana 5-year-olds spontaneously mentioned a pet when asked "who do you turn to when you are feeling sad, angry, happy, or wanting to share a secret?" Even more interesting: when comparing parents, friends, and pets, elementary school children considered their relationships with their pets as most likely to last "no matter what" and "even if you get mad at each other." Among pet-owning children, those who did turn to their pets for support were rated by parents as less anxious and withdrawn than those who owned pets, but did not seek such social support from them.

The second is nurturance. Since pets are dependent on human care, pets provide children with the opportunity to learn about how to care for another being. Further, Melson argues that the development of nurturance underlies future effective parenting, non-family childcare, and caregiving for the elderly, sick, and disabled.

One study of 5-6 year olds showed that those more attached to their pets showed greater empathy towards peers. Another study of 7 and 10 year olds showed that those who reported more "intimate talks" with their pets, also reported more empathy.

It is important to note that most of these studies are correlational, and it is therefore difficult to make any causal claims. For example, the association between pet-caring and empathy identified may be due to the possibility that parents obtain pets for children who are already empathic. Or, empathic children may be better at bonding with animals.

I agree that more research needs to be done on child-animal relationships, particularly within the context of the family. Many children (and adults) consider their pets as family members. Some children consider their pets as though they were younger siblings, peers, or even as security-providing attachment figures. One study suggested that both adults and children within a family context may deflect their emotional responses onto their pets (a mother is angry at her children, but yells at the dog instead), or routing communication to their pets meant for other family members (a father talks to the cat intending his son to overhear). It would be interesting to know how pets alter and are altered by the dynamics of the family system.

Melson, G. (2003). Child Development and the Human-Companion Animal Bond American Behavioral Scientist, 47 (1), 31-39 DOI: 10.1177/0002764203255210

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â"Babies will smile at, hold, follow, and make sounds in response to the live animals more than in response to the toys."

Couldn't that just mean that the baby sees the real thing as a better than the toy? In the future you'll be able to make a toy that most people couldn't differentiate from the real thing, never mind a baby. Also if you made a toy that was even better than the real thing surely babies would smile at, hold, follow, and make sounds in response to that toy (e.g. a cat that could fly) more than in response to the real (less cool) animals.

I'm just saying that to me this seems like the baby's ability to decide what is more awesome, rather than its ability to classify things as biological or artificial.

I just love your blog; I swear when I read it sometimes that I picked the wrong field :). Child-(non-human)animal relationships are so fascinating and, in my opinion, very essential. What a fascinating study you've shared! Thank you!

I have to disagree with Jools, I'm afraid. I don't think the 'coolness' of the animal or toy has anything to do with it. A living, breathing animal (I count fish as breathing) behaves very differently from even the most sophisticated toy. Children instinctively react to a real mind and a real life behind real eyes, and I suspect most would prefer the company of a real kitten than that of a talking, flying toy.

Melson also points out that even caring for birds and other wild animals help children to see themselves as nurturing and care-giving.
I also find it interesting that the number of bonds within a family to humans is shrinking while the number of bonds within the "family" (including pets) is increasing.
Really enjoy when you right about dogs especially.
Thanks

Some remarkable research you have collected! Thanks a million,I am conducting a dissertation about the interraction and benefits of young children with animals and it was just what I needed! :)

Coming from personal experience of having childhood pets, I definitely find some of the points to be true (at least in my case). I was an only child growing up, so my parents decided to buy a dog to be my companion. My parents were usually either working away from home or at home, so my dog and my momâs two cats provided me with a great deal of social interaction. I recall one memory of me carrying around my dog and talking to her, pretending we were preparing for an adventure. It didnât matter than the only response I got from her was a blank stare, having something to talk to and that would always be there for me mattered more. When my momâs cats died the year I was in sixth grade, I started to get a better understanding of death. Having childhood pets can be great, but the pets dying (hopefully from old age...) around the time you become a teenager is rough. Looking back on it, I see it as a parallel of the end of my childhood. Your research gave a very interesting biological/social perspective of something I can relate to on a very personal level.

Since I was 4 or 5 years old, I have had my standard poodle Tootsie by my side, through thick or thin, and she has never stopped loving me unconditionally. I think thatâs the greatest thing about a dog. You could have bad breath, the worst body odor in the world, or a bad hair day, and no matter what, your dog will still love you. I think that this blog raises a good point that having a dog is more than just having a pet; itâs having a companion. Dogs help us get through tough times in our lives. They listen, and they care, and they can help us express our emotions. It urks me when parents deprive their children of a pet, either because they donât want to spend the money on the animal, or because they donât think itâs necessary. It shouldnât be about the money, or the fact that youâll have to feed the dog and pick up his/her defecations. Itâs about happiness, and I canât think of one thing in this world that makes a family more complete, after all of the children, than a pet and a companion. Pets not only benefit you, but they also benefit the people around you. For example, my dog is a Therapy Dog. She has an official license and everything, and every day, she goes to work with my mom, who is a psychotherapist. The difference my dog makes in her office is exponential! My dog provides comfort for people in my momâs office, and makes my momâs office environment more relaxing. I will say that my dogâs work consists mostly of sleeping, but just her presence in my momâs practice is enough to help her patients that much more. You can learn more about therapy dogs at http://www.tdi-dog.org/. I really enjoyed reading this article, and I hope that it will inspire people to realize just how amazing pets truly are.

Child-animal relationships and their effect on childrens' development and personality is such an interesting field of study and I think it is introduced well in this article. It should have much more attention as a field of study!

I would like to ad that I am positive that human/pet bonding also helps adults to develop socially and emotionally. I suggest such relations have the power to indirectly improve the quality of their human/human relationships through the learning/improvement of social skills, empathy and 'theory of mind' (to understand another being fundamentally very different from one self).

I think that in some cases the basics of social interaction, bonding and reciprocality may be learned more easily from a dog than a human, due to the animal's simplicity and absence of complicated social agendas.

Then when the basic building blocks are in place and well understood, the skills can be generalised to build meaningful, loyal relationships to other people.

I think that effect can help socially vulnerable/delayed kids as well as adults to learn crucial social skills and begin to connect better to other people, as well as improve the general relationship-quality of normal kids and adults.

I am saying that it automatically happens ...just that the potential is there, and it has that effect on some.

I am saying that it automatically happens

should say: I am NOT saying that it automatically happens

Origins of Morality: Puppet-Show Style!

jgoldman — Thu, 23 Sep 2010 09:00:00 +0000

Origins of Morality: Puppet-Show Style!

Morality and convention are so mired in culture that it may seem near impossible to determine the extent to which biology and environment give rise to it. And yet it is possible to investigate the evolutionary origins of morality. Research with infants - especially pre-verbal infants - who have not yet been sufficiently exposed to most cultural institutions, can provide an opportunity to determine what the evolutionary and developmental building blocks are for complex moral reasoning.

Human adults evaluate individuals very quickly, on the basis of both physical and behavioral traits and characteristics. What are the origins of this capacity? One group of researchers wanted to determine if preverbal infants would distinguish individuals that might help them from individuals that might be harmful. In this study, 6- and 10-month-old infants watched a short puppet show in which a "climber" shape was struggling to climb up a hill. In some trials, the climber is helped by another shape, and in other trials, the climber is hindered by a third shape. By using simultaneously two methods common in infant studies, the researchers attempted to discern whether young infants were evaluating other individuals on the basis of their behavior.

The first method was the traditional looking-time measurement, also known as the violation of expectation paradigm. This method works because infants tend to look longer at something that is unexpected or surprising. After habituating the infant to alternating "helping" and "hindering" puppet shows, the "climber" would approach either the helpful shape or the harmful shape. If the infants had formed representations of the intentions of the "helper" and "hinderer" based on their actions, then the infants should be surprised - and therefore look longer - when the climber goes to hang out with the hinderer, than when the climber goes to hang out with the helper. The 10-month-olds looked significantly longer when the climber approached the hinderer, suggesting that they were surprised by the climber's behavior. However, the 6-month-olds showed no preference, and looked equally at both displays.

The second method was the toy-choice measurement, also known as the choice paradigm. After viewing the presentations, the infants were offered a tray from which they could reach for a replica of the helper and hinderer shapes used in the puppet shows. Would the babies rather play with the helper or the hinderer? The infants overwhelmingly reached for the helper: 87.5% of the 10-month-olds, and 100% of the 6-month-olds.

Why would it be that the six-month-olds would appear to have accurately encoded the social actions when using the choice task but not the looking-time measurement? It appears that both 6- and 10-month-olds can engage in the social evaluation of others, more generally, and therefore reached for the helper shape. However, it is possible that 6-month-olds are unable to infer the social evaluations of others, while 10-month-olds are. In order to be surprised that the climber chose to approach the hinderer, the infant would have to possess at least a rudimentary theory of mind. He or she would have to know that the climber had a mind that was also evaluating the behavior of the helper and hinderer.

In social situations, individuals must decide relatively quickly, based on limited information, whether or not to trust somebody else. That the ability to rapidly evaluate another individual on the basis of its actions towards another unrelated individual emerges so early in infancy suggests that it is critical to the processing of the social environment. This ability also seems critical for the development of more complex moral reasoning. The ability to distinguish the more fuzzy notions of right and wrong may emerge from the more basic evaluations of positive and negative actions. Indeed, the authors make exactly such an argument: "The social evaluations we have observed in our young subjects have (at least) one crucial component of genuine moral judgements: they do not stem from infants' own experiences with the actors involved...Their evaluations were made on the basis of witnessed interactions between unknown individuals: the infant, as an unaffected, unrelated (and therefore unbiased) third party, is nonetheless rendering a judgement about the value of a social act."

These findings support the claim that the social evaluations of others forms one building block for more complex moral thinking, and is potentially innate.

Hamlin JK, Wynn K, & Bloom P (2007). Social evaluation by preverbal infants. Nature, 450 (7169), 557-9 PMID: 18033298

jgoldman Thu, 09/23/2010 - 05:00

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Wow, you are having a lot of really good posts about really interesting research papers out lately - dogs and all - and in such short order. How you even manage to find and read them all, let alone blog about them? You sleep how many hours at night?

Really interesting... I always wonder what's going on behind those pudgy, confused little faces.

Don't the infants' preferences for the "positive" actor strike you as a hallmark of empathy, rather than necessarily being due to some innate differentiation between right and wrong?

Well, it's not really about right and wrong, as much as a more basic sense of helpful individual versus harmful individual - friend versus enemy - someone to trust versus someone not to trust. The ideas of right and wrong are far more informed by culture, the way I see it.

It isn't clear to me how empathy fits into this scenario, especially since the child isn't given the option of reaching for the "climber" - only the "helper" and "hinderer."

I will read the whole paper later, but it your report seems to suggest that a child can detect goal-directedness and some sort of positive ideal in another.
How might the child respond if given the choice between a 'hinderer' and some third neutral character? Would they avoid the 'hinderer' based on some kind of judgement? If so, I would argue that might be stronger evidence that they have some kind of proto-social-disireability thing going on... It sort of seems like they've only got half the story.

Why would the child perceive this as a social issue? He or She could also just detect one scenario where things are going smoothly, they have a constant flow in one directon, whereas the second scenario show a force that acts oppositly and the one directed flow of happening is hindered by something. I mean if they would have used some other forms without those eyes, then they would get the same results, so this isn't primarly about social morality imho.

Machines Learn How Brains Change

developingintelligence — Wed, 15 Sep 2010 07:20:16 +0000

Machines Learn How Brains Change

In last week's Science, Dosenbach et al describe a set of sophisticated machine learning techniques they've used to predict age from the way that hemodynamics correlate both within and across various functional networks in the brain. As described over at the BungeLab Blog, and at Neuroskeptic, the classification is amazingly accurate, generalizes easily to two independent data sets with different acquisition parameters, and has some real potential for future use in the diagnosis of developmental disorders - made all the easier since the underlying resting-state functional connectivity data takes only about 5 minutes to acquire from a given subject.

Somehow, their statistical techniques learned the characteristic features of functional change between the ages of 7 and 30 years. How exactly did they manage this?

First, they started with three data sets of resting-state BOLD activity; the first consisted of 238 resting-state scans from a 3T scanner from 192 individuals between 7-30 years of age. The second was of 195 scans from 183 subjects aged 7-31 years, each scan being an extraction of "rest" blocks from blocked fMRI designs which were then concatenated, having initially been acquired on a 1.5T scanner and a different pulse sequence than the first dataset. The third data set was 186 scans of 143 subjects aged 6-35 performing linguistic tasks, with task-related activity regressed out, using the same pulse sequence as the second dataset.

All the data was transformed to a single atlas and sent through a standard artifact-removal pipeline; next, activity in each of 160 10-mm spherical ROIs was calculated for each image in each scan, with the ROIs determined by a series of five meta-analyses the authors undertook on data of their own (wow!). The full cross-correlation matrix of correlations of ROIs across time was then calculated (yielding 12,270 correlations for each scan) and z-transformed.

Next they take this massive correlation matrix and use a support vector machine (SVM with soft margin, including a radial basis function "kernel trick") to classify each timeseries as belonging to a child (7-11 years old) or an adult (24-30 years old), tested with leave-one-out-cross-validation. They kept only the highest-ranked 200 features of the trained SVMs for further analyses (a process of recursive feature elimination didn't really help, so they just stuck with 200). Across all validations, the same set of 156 features consistently ended up in the top 200, and were used for visualization of the feature weights. In this step they could classify adults vs. children at 91% accuracy.

They next used support vector regression to predict, based on the retained 200 features, the age of the subject in the scanner. Predicted ages were converted into a "functional connectivity maturation index" which had a mean of 1.0 for ages 18 to 30 (we'll come back to this), and revealed beautiful curves you've no doubt seen elsewhere by this point:

The best-fitting line here is actually either the Pearl-Reed (gray line - used in other contexts to model the growth of human populations in settings with limited resources) or the Von Bertalanffy (black line - used to model the growth of animals). The same basic effects were replicated on all three data sets.

The rest of the paper is mostly dedicated to visualizing what exactly it was that the SVMs were basing their surprisingly accurate predictions. It turns out that twice as much of the predicted age-related variance was explained by functional connectivity that decreased with advancing age as by that which increased with age. Moreover, decreasing connectivity was more common among nearby regions, whereas increasing functional connectivity tended to occur among more far-flung regions (similar to the local-to-distributed shift discussed previously). Functional connections that increased with age were more aligned in the anterior-posterior dimension than those that decreased with age; the single most age-discriminative set of ROIs was the "cingulo-opercular" network (also discussed previously), and the most age-discriminative individual ROI was the right anterior prefrontal cortex.

If all that wasn't complicated enough, here's a glimpse of the paper's money shot:

Obviously, this is an incredibly impressive set of results with real-world value. But what are some of the potential pitfalls here?

One is that the classification actually took place in higher-dimensional space (>200 dimensions, as I understand it), meaning that the results are dependent on interactions of changes in functional connectivity among and within the 156 features visualized above. This kind of thing is not easily captured in the way the results have been visualized.

A second thing to be wary of is the conversion of chronological age to the predicted brain maturity index. I'm not following why exactly this conversion was necessary, but I assume it was due to a fall-off in the classifier's accuracy for predicting the age of subjects who are, in reality, between the ages of 18 and 30. This likely indicates that functional connectivity asymptotes in its sensitivity to change in functional connectivity around that time. In other words, it's likely not capturing whatever "wisdom" a 30 year old might have that differentiates them from an 18 year old.

(Assuming such a thing actually exists, it seems like it's not "in" the functional connectivity data. On the other hand, some of their data sets may have under-sampled the older part of the age distribution - perhaps wisdom just takes statistical mega-power to detect.)

These caveats aside, it's really beautiful work, and I believe it will really help real people really soon (TM). That's far more than can be said about most of the work being done in this area, which is far more theoretical in nature.

developinginte… Wed, 09/15/2010 - 03:20

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It's not that easy to tell from the graph (which I realize illustrates only 2 dimensions) but it looks like there are non-linearities. I wonder if a non-linear method like k-NN would outperform it.

Researchers should release the raw data for things like these. There are lots of data scientists who would love to come up with better methods of classification and modeling. Or they could launch a competition at kaggle.com.

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Origins of Mind 101

jgoldman — Fri, 10 Sep 2010 06:35:00 +0000

Origins of Mind 101

If I had to describe the mission, the point, the raison d'etre of the entire field of psychology in just one sentence, I would say: Psychology aims to determine the relative extents to which biology and experience determine cognition and behavior." And, as you might expect, there are widely differing schools of thought. Nativists emphasize genetics, biology, and innate mechanisms. By contrast, the empiricists insist that babies are born into the world with no a priori knowledge thereof, and just a powerful statistical associative learning mechanism by which they piece together their understanding of reality. In reality, it is likely that there are some things that are innate and some things that require learning. Other mechanisms are probably innate but require experience or learning to properly "tune" or "sharpen" the system.

Rene Descartes speculated that the self (or more specifically, the mind) perceives its own body due to the senses. However, he was aware that the senses could be fooled, and explained the apparent limits of sensory perception with the wax argument: Consider a piece of wax. You perceive certain characteristics about it, such as shape, texture, size, color, smell, etc. But when you move the wax towards a flame, the perceived characteristics change as the wax begins to melt. You know it is still the same piece of wax, but the senses inform you however that the characteristics have changed. So, Descartes argued, sensory perception is not sufficient to properly understand the nature of the wax; instead, he must use his mind. He wrote "...And so something which I thought I was seeing with my eyes is in fact grasped solely by the faculty of judgment which is in my mind." Descartes thus discarded perception and focused solely on deduction as a useful method by which we can come to know the world.

Figure 1: Rene Descartes, 1596-1650.

Later, Descartes modified his initial claims regarding the role of sensory perception. In his third and fifth Meditation, he constructed two different proofs that God was benevolent. And, since God was benevolent, Descartes reasoned, he could have faith in the reality provided to him by his senses, since God provided him with a sensory system that was not designed to deceive him. Out of this argument he established the possibility of acquiring knowledge about the world based both on deduction AND sensory perception.

In 1637, Descartes published the Discourse on the Method, in which he argued that the geometric principles underlying the knowledge of space were innate, and were accessible not only to vision but to any sensory modality. He used a blind man with a stick as an example. For the blind man to discover the shape and position of objects, he had to match up each tactile percept with a mental spatial framework, structured around the principles of Euclidean geometry.

Descartes further argued that any individual, exploring the world through any mode (tactile, visual, auditory, or otherwise) faces the fundamental problem of the blind man, and that he or she must draw on tacit geometrical knowledge to solve that problem. Moreover, Descartes argued that such a mental geometric template must be innate: since such a template structures all perceptual experiences, the template itself cannot be acquired by experience.

The contrast to the nativist tradition of Descartes is the empiricist tradition of George Berkeley. Berkeley, also known as Bishop Berkeley, was a philosopher in Ireland and England in the 1700s, and was born thirty-five years after Descartes died. He was also the namesake of UC Berkeley and the town around it.

Figure 2: George Berkeley, 1685-1753.

Berkeley argued that knowledge of the world could only be obtained through direct perception, and that conscious awareness of those perceptions was required for the perception to exist. He wrote, in Towards a New Theory of Vision, in 1709:

I appeal to any one's experience, whether, upon sight of an object, he computes its distance by the bigness of the angle made by the meeting of the two optic axes? ... In vain shall all the mathematicians in the world tell me, that I perceive certain lines and angles which introduce into my mind the various ideas of distance; so long as I myself am conscious of no such thing.

In this way, Berkeley continued the empiricist tradition (following, for example, John Locke), arguing that there were no innate systems of knowledge; instead, everything could be learned through experience, and all that was required in the mind was a general system for statistical learning.

What would it take to prove that a cognitive system is innate? If the human mind is built upon evolutionarily ancient building blocks that allow us to perceive and reason about the world, then:
(1) Those building blocks should be present at birth.
(2) Those building blocks should be present in other animals.
(3) Those building blocks should be universal across cultures.
(4) Possibly: those building blocks should have distinct neural substrates.

For most of the history of philosophy and psychology, people have assumed the opposite. John Locke wrote, in An Essay Concerning Human Understanding in 1689 (emphasis added):

Let us suppose the mind to be, as we say, white paper [tabula rasa] void of all characters, without any ideas. How comes it to be furnished? Whence comes it by that vast store which the busy and boundless fancy of man has painted on it with an almost endless variety? Whence has it all the materials of reason and knowledge? To this, I answer, in one word, from experience.

Similarly, William James wrote that "the baby, assailed by eyes, ears, nose, skin, and entrails at once, feels it all as one great blooming, buzzing confusion."

The basic argument is that infants come into the world knowing essentially nothing. They are equipped with basic sensory mechanisms and a powerful statistical brain that is highly skilled at detecting and learning associations between different sensory inputs. Throughout development, the argument goes, children learn more and more associations until they have the same kind of mind as human adults do.

The prediction that follows from this is that adults should always be better at cognitive tasks than infants. This, however, is not the case. For example, human adults are far better at distinguishing among human faces than among monkey faces. This is probably due to experience - humans develop expertise in distinguishing human faces because they spend most of their time with humans. But 6-month-old infants, before experience has significantly guided development, are actually able to accurately distinguish among monkey faces as well as among human faces.

Figure 3: Infants were able to distinguish among monkey faces as well as human faces. Adults were only able to distinguish among human faces.

This cognitive skill, facial identification, is actually better in infants than in adults, suggesting that there is an innate template for face recognition and for distinguishing among different individuals, and experience simply serves to build expertise. If facial recognition had to be entirely constructed, then you would expect infants not to distinguish among human faces as accurately as adults, let alone among monkey faces.

More and more, we are finding that the infant brain is not a "blooming buzz of confusion." Instead, the infant brain seems born capable of sophisticated reasoning about the world. The key is to figure out the proper way of testing and identifying those abilities.

Pascalis, O. (2002). Is Face Processing Species-Specific During the First Year of Life? Science, 296 (5571), 1321-1323. DOI: 10.1126/science.1070223

Landau B, Gleitman H, & Spelke E (1981). Spatial knowledge and geometric representation in a child blind from birth. Science (New York, N.Y.), 213 (4513), 1275-8. PMID: 7268438

jgoldman Fri, 09/10/2010 - 02:35

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The infant brain may not be a "blooming buzz of confusion" but I can't say the same for many grown-ups I know.

Are there any credible phych/science/philosophers who will still argue for either fundamental extreme? Seems at least that nuance has become the norm, no?

"Psychology aims to determine the relative extents to which biology and experience determine cognition and behavior."

Pretty good sentence.

I have an odd thing with collecting these sorts of short explanations for various fields of study. Metaphors are good too. I once heard one comparing psychology to cars (or was it brains to cars) that was interesting.

"Psychology aims to determine the relative extents to which biology and experience determine cognition and behavior."

One problem I have with this sentence is that the process by which experience affects cognition and behavior is biological, since the brain is nothing more than a biological entity (unless you believe in vitalism, of course).

But otherwise, great post! I love learning about the history of scientific ideas. For some reason, hearing about what people used to think makes learning what is known now WAY more interesting!

So facial recognition is a "if you don't use it, you lose it" ability. I'm reminded of isolated instances of blind people getting corrective surgery and then being unable to remember faces or being able to identify an object as a door because of differing styles/shapes. Nice work here!

The 'Tabula Rasa' v.s. innate knowledge is old, almost irrelevant phylosophical stuff. The modern paradigm was developed especially by Kant - the baby has no notions, no innate knowledge, but he has innate faculties, innate capabilities, and, hence, a very specific way in which he organizes experience.

@6 and @1: You're right, its an old debate, and in general things are more nuanced now, and most people believe that there is a mix of innate knowledge systems and things that must be learned by experience. But for just about every individual knowledge system, there are those who would favor an innate mechanism, and those who would favor associative learning. So, still, I think the debate is important. Even still, as Kelsey (@4) pointed out, it is also useful to place new data in the context of older perspectives.

@5: Yeah, sort of. We're born with an innate face template that gets sharpened or tuned with experience. Similar idea as the "sensitive period" for language. And since we don't spend our time with monkeys, we don't ever sharpen our abilities to discriminate among individuals. Only with lots of exposure and practice can a human adult learn to make those distinctions.

Apparently, wild crows are quite good at recognizing individual human faces (as well as faces of their own species, I assume).

One wonders if there was some evolutionary advantage for crows to distinguish between dangerous and non-dangerous humans.

It seems they also have long memories and "hold a grudge" against humans who've crossed them.

http://www.newscientist.com/article/dn18429-if-you-think-a-crow-is-givi…

Since I could distinguish the monkey and the human faces, does that make me an infant or the missing link?

Just kidding. Thanks for laying out both Descartes' and Berkeley's progression of thought.

Liked the historical stuff! A few follow-up posts that comprise a brief history of psychology a la Jason would be engaging reading.

Still chewing on the one sentence summary of the whole field, however...even now I'm not quite sure why it didn't sit right with me, even though others here seemed to gel with it.

Possibly it's because it frames the entire discipline in terms of the Nature vs Nurture debate.

Aren't there psychologists working on problems besides nature vs nurture?

I don't see how this conclusion must follow.

It seems just as possible that basic object recognition and simple perceptual abilities such as edge/shape detection is innate, and face recognition skills must be learnt. For instance, at first the two monkey faces look the same to me, but if I try hard, I can see that they are different e.g. the monkey on the left has a smooth hairline just above the eyes, while the hairline of the monkey on the right seems more jagged.

Maybe babies (and people with prosopagnosia) can see these basic perceptual differences just as well as adults. But in adults who have developed skilled facial recognition systems, this low level perceptual information is less important compared to the fast output coming from the face recognition system. This face recognition system is not innate, but has been trained over years of exposure to faces, and it just so happens that the two monkey faces don't have differences that are relevant to the fast, face recognition system.

Jason:

In answer to the question...

"What would it take to prove that a cognitive system is innate? If the human mind is built upon evolutionarily ancient building blocks that allow us to perceive and reason about the world, then:"

Are the 4 items below accepted scientific propositions, your interpretation, or what?

(1) Those building blocks should be present at birth.
(2) Those building blocks should be present in other animals.
(3) Those building blocks should be universal across cultures.
(4) Possibly: those building blocks should have distinct neural substrates.

And can you explain exactly what you mean by number 4)?

Mark

Very interesting, esp. the stuff from Descartes' Discourse, but I'm surprised you didn't mention Molyneux's problem (<http://plato.stanford.edu/entries/molyneux-problem/ )

Re. comment 6: Your comment raises this interesting question: can there be a mental ability (a bit of know-how) without any knowledge of facts (knowledge-that)?

What Are The Origins of (Large) Number Representation?

jgoldman — Tue, 17 Aug 2010 07:30:00 +0000

What Are The Origins of (Large) Number Representation?

This post considering the evolutionary origins of numerical cognition, specifically in terms of the approximation of large numbers, is meant as a companion to this week's series on the developmental origins of numerical cognition and developmental dyscalculia, at Child's Play.

What are the origins of number representation in the mind? Are there any innate building blocks that contribute to our understanding of mathematics and number, or must everything be learned?

Number is an important domain of human knowledge. Many decisions in life are based on quantitative evidence, sometimes with life or death consequences.

Figure 1: Fight or flight?

By now you probably have come to expect that I'll be arguing that there are several innate "building blocks" of cognition that give rise to more complex mathematics. To start with, what are some of the arguments proposed by the empiricists?
(1) Number knowledge is entirely conceptual - it requires seeing objects as belonging to sets;
(2) Number knowledge is abstract. You need to understand the similarity between 3 people, 3 objects, 3 sounds, 3 smells, 3 dollars, 3 seconds, 3 hours, and 3 years;
(3) It doesn't appear to be cross-culturally universal. Some cultures have more advanced mathematics than others; and
(4) babies and monkeys can't do long division.

Surely, humans have something unique that allows us to do things like multivariate regression and construct geometric proofs, however, but let's start at the beginning. I will hopefully convince you that there is an evolutionarily-ancient non-verbal representational system that computes the number of individuals in a set. That knowledge system is available to human adults and infants (even in cultures that don't have a count list), as well as to monkeys, rats, pigeons, and so forth.

In the first study (of human adults) that we'll consider, participants were presented with arrays of dots on a computer screen that were presented only for a fraction of a second. In that time, the participants had to determine if the second array had more or fewer dots than the first array. They controlled or counterbalanced dot size, density, shape, and things like that. How did they do in this task?

Figure 2: Results. They were at chance on trials comparing 32 and 34 dots (center). All other comparisons, adults demonstrated above-chance discrimination.

Here's the important point. If they were counting, then they should have been able to discriminate 32 versus 34 dots just as easily as they were able to discriminate 8 versus 10 dots. Also, if they were counting, it should have taken then longer to count 32 versus 64 dots, than for 8 versus 16 dots. Since the dot arrays were displayed for the same amount of time, and they were able to discriminate both of those sets of numerosities equally well (and perfectly), it follows that they weren't counting.

It turns out that the discriminability of two numerosities depends not on the total number of objects, but on the ratio between the two numerosities. Notice that 32 vs. 64 and 8 vs. 16 have the same 1:2 ratio. This also implies that the mental representations of these numerosities are inexact - they are approximations, not exact numbers.

Figure 3: Where the ratio was 1:2, responses were perfect. Success rate decreased as the ratio decreased. When the ratio was 1:1.1, success was basically at chance, but considerable success at 1:1.15.

Is this limited to the visual domain? In the next experiment, participants saw a similar array of dots, and then they heard a set of sounds. This cross-modal comparison (73% accuracy) was almost as accurate as the visual comparison alone (76% accuracy). The participants were also asked to add sets of objects. They were shown two arrays sequentially, and asked to add mentally approximate the total number of dots on both arrays, and shown a third array. They were asked if the sum of the dots in the first two arrays more or less than the total amount of dots in the third array. This resulted in 72% correct responses. Last, this was done cross-modally. They were shown a dot array, then given a sequence of sounds, and asked to add them. Was the sum of the dots and the sounds more or less than the total amount of dots in a new, third, array? Accuracy was 74%. Accuracy was roughly equal across all four of these conditions, suggesting that numerical representations are abstract. It also means that these approximate abstract representations contribute to our ability to add.

Figure 4: Results. Equal success for each condition.

"But," the empiricist says, "these representations have been mapped onto verbal numerals. Even though you might have an approximate estimation of the number of dots, you still use language. You might think 'that's about 50 dots' or 'it seems like there's around 300 dots.' These people have spent years learning and using formal arithmetic." And in response to the empiricist, the nativist says: "Fine. Have it your way. Bring on the babies and animals."

So we gather a group of six month old babies who don't have language yet. We can't ask babies which array has more dots, so we use a habituation paradigm. We show the babies arrays with the same number of dots (say, 8 dots) until they get bored of it and spend less time looking at it. Then we show them a new array (say, 16 dots). Do they look longer at the new array of 16 dots than at a new array of 10 dots? If so, that means that they discriminate 8 versus 16, but not 8 versus 10.

And so it was. Infants successfully discriminated 8 vs. 16, 16 vs. 32, and 4 vs 8. They failed to discriminate 8 vs. 12, 16 vs. 24, or 4 vs. 6 dots. So infants, too, show a ratio limit, though the critical ratio is higher for infants (1:2) than for adults (1:1.15).

How general is this ability? Does it work for sounds as well? A new group of six-month-old and nine-month-old infants were placed between two speakers, and were habituated to a number of sounds coming from a certain direction. Instead of looking time, the measurement was whether or not the infant turned his or her head to orient toward the source of the sounds. They were familiarized to, for example, 8 sounds or 16 sounds, and then tested with 8 and 16 sounds. The findings from this task were similar to the findings in the dot task.

Six-month-olds discriminated 8 vs. 16 and 4 vs. 8 sounds, but failed at 8 vs. 12 and 4 vs. 6. The nine-month-olds discriminated 8 vs. 12 and 4 vs. 6 sounds, but failed at 8 vs. 10 and 4 vs. 5 sounds. Again, discrimination of numerosities showed a ratio limit, though discrimination gets sharper with age.

Let's push the question a bit farther. Approximate numerical representation exists for visual objects as well as auditory sounds. What about for actions?

Infants were habituated to a cartoon in which a rabbit jumped either 4 times or 8 times. The total distance of the movement of the rabbit was equivalent, such that the each of the 4 jumps were twice the distance of each of the 8 jumps. This allowed the rabbit to end up at the same location at the end of each set of jumps - so the infants couldn't rely on physical displacement as a correlate of number of jumps. The findings were the same as the dots and sounds. Representation of number is truly abstract, even in infants.

To recap: Before learning to count or learning arithmetic, infants represent and discriminate large numerosities. These representations are approximate, and subject to a ratio limit. These representations are also abstract, and the same ratio limits applies to objects, sounds, and actions. This capability is present in infancy, though it increases in precision through development.

On to the animals.

In the 1950s and 1960s, Dr. Francis Mechner did a series of conditioning experiments with rats. In one such study, rats were trained to press a lever 4, 8, 12, or 16 times in order to receive a reward. Tension on the lever was controlled, so that the rats couldn't rely on total effort as a correlate of the number of level presses.

Figure 5: Presses on the lever by rats.

These data indicate that rats also have inexact, approximate representations of large numerosities, and that there is also a ratio limit. Accuracy decreases as the target number of lever presses increases.

Some years ago, a group from Harvard investigated this question in cotton-top tamarin monkeys as well. They did the same auditory discrimination experiment with the monkeys as had been done previously with infants. The monkeys were habituated to a sequence of sounds coming from the right or left, and then presented with a new number of sounds. Again, the turn of the head to orient towards the sound was used as an indication of discrimination. Their performance was similar to the 9-month-old infants: they discriminated 4 vs. 6 and 8 vs. 12, but not 4 vs. 5 or 8 vs. 10. They could discriminate 2:3 ratios, but not 4:5 ratios.

How evolutionarily-ancient is this cognitive capacity? Our common ancestor with tamarins is relatively recent, compared to say, with fish. So let's look some Italian fish.

Figure 6: Eastern mosquitofish (Gambusia holbrooki). This one is about 4cm long.

Female mosquitofish like to hang out with groups of other females as protection from sexually harassing males.

So you take a female mosquitofish, and you let her habituate to the fishtank. On either side of a long fishtank there are two additional groups of females of differing sizes, in their own tanks.

Figure 7: Something like this.

Meanwhile, you take a male mosquitofish and you deprive him of any females for a whole week. Sucks to be him. You introduce him into the tank with the female, and its game on. He desperately wants the feel of her cold, wet, slimey, scaley body. He can't wait to make sweet fishy love. He sees her from across the tank. He works up his nerve and says, (channeling his best Walter Matthau impression) "Maria, there may be lots of fish in the sea, but you're the only one I want to mount over my fireplace."

If he makes at least 10 attempts to have his way with the female in the first five minutes, then you record which group of fish the female tries to join. She should prefer to hang out with the larger group of females.

When the two groups of female fish were different according a 1:2 ratio, she always chose the larger group, but when the ratio was 2:3, she chose randomly. Just like the monkeys, and just like the human infants.

Figure 8: Success for 1:2 ratios, but not for 2:3 ratios.

What can we conclude from this series of studies?

Animals and humans spontaneously represent large (greater than 4), abstract, approximate numerosities. Animals, human infants, and human adults, show the same ratio signatures. Adult tamarins are on par with 9-month-old human infants. With age or training, discrimination ability becomes more precise, and the the critical ratio is reduced a bit.

The large number cognitive system is evolutionarily-ancient and non-verbal, and is likely innate.

Next up, later this week: small numbers.

Barth H, Kanwisher N, & Spelke E (2003). The construction of large number representations in adults. Cognition, 86 (3), 201-21. PMID: 12485738

Lipton JS, & Spelke ES (2003). Origins of number sense. Large-number discrimination in human infants. Psychological science : a journal of the American Psychological Society / APS, 14 (5), 396-401. PMID: 12930467

Mechner F (1958). Probability Relations within Response Sequences under Ratio Reinforcement. Journal of the experimental analysis of behavior, 1 (2), 109-21. PMID: 16811206

Hauser, M., Tsao, F., Garcia, P., & Spelke, E. (2003). Evolutionary foundations of number: spontaneous representation of numerical magnitudes by cotton-top tamarins. Proceedings of the Royal Society B: Biological Sciences, 270 (1523), 1441-1446. DOI: 10.1098/rspb.2003.2414

Agrillo, C., Dadda, M., & Bisazza, A. (2006). Quantity discrimination in female mosquitofish. Animal Cognition, 10 (1), 63-70. DOI: 10.1007/s10071-006-0036-5

jgoldman Tue, 08/17/2010 - 03:30

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But... but... but... uh... the PirahÃ£!!!

(kidding)

Here's one for you. I am a writer with a problem; my brain wants to quantify punctuation, specifically colons, semicolons, and commas. I will begin editing a page using standard rules of grammar, but soon I am using a different system based on a ratio, roughly 1 colon: 3 semicolons: 6 commas. This is not the limit per page, but a ratio for each page. Periods are exempt.

This 'automatic' quantifying of punctuation is a real pain! I have to go over a ms. many times, and while trying to correct the mistakes I am apt to lapse into the ratio system without knowing it.

Excellent post. Thanks!

This powers of two recognition and ability to distinguish doubled up/down numbers brings to mind so called "Peasant multiplication" which was a very common system for multiplication and division which relied only on the ability to multiply and divide by two, and addition and subtraction.

It's also impossible to avoid mentioning binary arithmetic I suppose.

I once got bitten by a mosquito fish; ended up with filaria....

It would seem essential that being able to identify relative numbers and numbers in a group is very basic for animals: a pride of lions must decide whether or not to contest another pride's territory, or discretely move on - do they outnumber us, how many males vs. females and cubs; weight, fitness, health. Even an "inventory" of available prey. What we call mathmatics is embedded in every form and function in nature.

Excellent post.

Is the cotton tamarin experiment the one done by Hauser that is under investigation at this time?
This obviously doesn't take anything from the conclusion or from the other studies, but I am not sure if it's one of the studies that were going to be under evaluation for possible "retraction"

Nope, it is not.

I don't understand two issues here:

1) Almost all the experiments deal with discrimination, so the best case scenario is that they tell us something about the number discrimination process, not about number representation - to this extent - discrimination is sensitive to ratios not pure subtractions - that's the only inference you could make.

2) In the rat study, the rats aren't comparing values (at least as presented here), they are responding to absolute values, and it looks like they do reasonably well. What point is there in saying that they are storing ratios not absolute values? I see the rat study to be showing something completely different from the rest of the studies - it is possibly the only one that could say something about the representation of numbers (as opposed to discrimination).

@10: The idea is in order to discriminate two quantities, you have to mentally represent the magnitude of each quantity. The conclusion made is that discriminations are made on the basis of approximate ratio instead of exact numerosity. The rat study demonstrates, with a different sort of task, that they too represent large numbers approxmiately, not exactly.

yes, discriminations are made with approximate ratios, this does not mean the numbers are stored as ratios.

The rats study was also claimed to have "a ratio limit", I'm not sure I follow this, given that it was about tracking absolute values.

I am not against saying that large number representations are "approximate". It seems reasonable. It is the further claim that somehow they are "ratios" that seems weird - cos the ratios are relevant ONLY for discriminatory purposes where there is a second number for ratios. Otherwise, you couldn't store a number as a ratio.

I forgot to mention: I really like your reviews / posts, so keep 'em coming! cheers!

I'm going to jump in with another anecdote about my "odd" relationship with mathematics. First, I need to mention that I score high on verbal / visual intelligence and have very low mathematical aptitude. As a geology student I faced 2 semesters of calculus based physics and 3 semesters of calculus. Baby stuff, I know, but daunting for me. I decided to take the physics semesters BEFORE the calculus course; it sounds crazy, but it helped.

What is odd is that I figured out how to navigate these "foreign" languages using a visual "code" that I made up, a metalanguage, I guess. I connected a description of problem type (thingy-symbol = thingy) with a check list of how to solve it. Gee whiz, it worked. I had no idea what equations "meant" -

I mention this because I suspect there are other people out there, for whom mathematics is not their "native language" who have had to do something similar.