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
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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.