Comparative Psychology

Performance Improves with Transcranial Random Noise Stimulation

developingintelligence — Mon, 21 Nov 2011 10:04:44 +0000

Performance Improves with Transcranial Random Noise Stimulation

Stimulating the brain with high frequency electrical noise can supersede the beneficial effects observed from transcranial direct current stimulation, either anodal or cathodal (as well as those observed from sham stimulation), in perceptual learning, as newly reported by Fertonani, Pirully & Miniussi in the Journal of Neuroscience. The authors suggest that transcranial random noise stimulation may work by preventing those neurophysiological homeostatic mechanisms that govern ion channel conductance from rebalancing the changes induced by prolonged practice on this perceptual learning task.

Over several experiments, a total of 99 subjects underwent transcranical random noise stimulation, consisting of an AC current of 1.5 mA intensity at random frequencies between 0.1 to 100 Hz (for low-frequency stimulation) or 100-640 Hz (for high frequency stimulation). Direct current stimuliation was similarly provided at 1.5mA. (In case you wanted to replicate this experiment at home, the company that sells the device used in this study has made it clear they're perfectly fine with selling you one for your own personal use ["Unser Service fÃ¼r Sie persÃ¶nliche Beratung"] - not that I'm recommending that!) At any rate, no artifactual visual perceptions were induced by these stimulations, and all women were tested during their follicular menstrual phase (at which point their cortical excitability is most similar to that of men). Stimulation was provided for approximately 4 minutes over the occipital lobe (or vertex, for control stimulation conditions) during each block of a visual orientation discrimination task. Subjects simply had to say whether a given stimulus was tilted clockwise or counterclockwise relative to a preceding reference stimulus.

Over the course of five successive blocks of this task, subjects undergoing high frequency random electrical stimulation performed consistently better than subjects undergoing any other kind of stimulation, including low frequency random stimulation, cathodal or anodal direct current, control stimulation to the vertex, or sham stimulation. The rate of change in performance was also increased in high frequency random stimulation relative to anodal direct current, which yielded no apparent learning effect - even though anodal direct current is typically thought to enhance neural activity and is in other domains helpful to performance. The authors even replicated these advantages of high frequency random stimulation (just relative to sham stimulation) in a second experiment.

And in case you think these effects are driven by demand characteristics, note that participants failed to correctly guess whether they received actual stimulation or placebo (sham) stimulation - indicating these effects are unlikely to be driven by any explicit perception arising from electrical stimulation. Moreover, anodal and cathodal direct current stimulation was associated with an increased report of itchiness, irritation and burning than the other conditions. In no case did reported sensations during stimulation correlate with performance (absolute R values <.1), and random noise stimulation was never differentiable from sham stimulation, neither in terms of explicit report nor subject ratings of various subjective experiences like itching, burning, irritation, pain, heat, or "iron taste".

So, how on earth is this happening? Fertonani et al suggest that repeated random stimulation at a high frequency can actually support temporal summation of neural activity, whereas anodal direct current will induce a facilitation that is followed by homeostatic re-regulation of the ion channel conductances and thus ultimately reduce neuronal excitability. I think the authors are reasonably careful to acknowledge that this particular scenario may be highly dependent on a number of factors, including the exact placement of reference electrodes, the exact stimulation parameters used, as well as possibly more interesting things like the cytoarchitectural features of the areas undergoing stimulation.

Nonetheless, Fertonani can't resist some speculations about another possible explanation for these effects: stochastic resonance. Stochastic resonance refers to the (apparently) paradoxical phenomenon by which the signal to noise ratio in a thresholded system can sometimes be enhanced following the addition of broadband noise, which may provide additional excitation that allows nascent signals to reach a criterial threshold for experiencing positive feedback. Originally, stochastic resonance was proposed as an explanation for the presence of ice ages throughout geological history, and has subsequently been (hypothesized to explain some neuropsychiatric phenomena; indeed, it has been observed in hippocampus, and a number of sensory regions). Fertonani et al carefully suggest that random noise stimulation could have beneficial effects by pushing the neuronal population "over the threshold" required for some form of positive feedback (perhaps due to recurrent activation or perhaps thalamocortical in nature) or by preferentially recruiting additional subthreshold neurons to participate in such neuronal population coding.

This of course is not mutually exclusive with the idea that random noise stimulation eliminated homeostatic mechanisms for regulating ion channel conductances, but I do tend to prefer the stochastic resonance interpretation. It's unclear to me why anodal direction current stimulation should ever benefit performance if these homeostatic mechanisms are so perniciously counterbalancing any changes that are being induced, unless such homeostatic mechanisms are simply more operative in visual cortex than over other regions.

An alternative explanation, unmentioned by Fertonani et al., is that their transcranial random noise stimulation effectively acted as a biological version of the simulated annealing process sometimes used to improve learning in artificial neural networks. In simulated annealing, the injection of random noise during learning can bump the system out of local minima in the energy landscape and promote better long-term performance. Although orientation discrimination is presumably a well-learned skill in the adults used in this experiment, there may be task-specific associative learning that is occurring over the course of the experiment, and such learning could conceivably be enhanced through this kind of annealing process.

At the same time, there are new reports that random noise stimulation is not effective in improving performance in tasks relying crucially on more anterior cortical regions - including everyone's favorite area, the DLPFC, in everyone's favorite task, the n-back. It is difficult to integrate these failures with a weight-based interpretation of short-term synaptic facilitation demonstrated by Itskov et al to be important for stabilizing attractor states in the prefrontal cortex. Indeed, random noise stimulation may decrease motor-related BOLD responses even as it increases corticospinal excitability. These confusing and sometimes conflicting results pose a significant challenge to any explanation of random noise stimulation invoking stochastically resonant, or annealing-sensitive, neurobiological mechanisms.

developinginte… Mon, 11/21/2011 - 05:04

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Artificial Intelligence

Comparative Psychology

Computational Modeling

If there was a way to increase the thought process without affecting motor skills, that would be awesome!
Makes you wonder what the frequencies that we are getting from cell phones and wi-fi.

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Architecture of the VLPFC and its Monkey/Human Mapping

developingintelligence — Thu, 17 Nov 2011 11:43:18 +0000

Architecture of the VLPFC and its Monkey/Human Mapping

If you ever said to yourself, "I wonder whether the human mid- and posterior ventrolateral prefrontal cortex has a homologue in the monkey, and what features of its cytoarchitecture or subcortical connectivity may differentiate it from other regions of PFC" then this post is for you.

Otherwise, move along.

The mid/posterior ventrolateral prefrontal cortex (pars opercularis and pars triangularis, or Brodmann's Areas 44 and 45) is very clearly different, both anatomically and functionally, from its anterior sector (which involves the pars orbitalis, or Brodmann's Area 47). It is also probably (though not yet certainly) true that these sections of posterior ventrolateral prefrontal cortex are functionally distinct from the inferior frontal junction area (i.e., at the junction of the inferior frontal sulcus with the precentral sulcus, and therefore dorsal to the pVLPFC areas I will be focusing on; it is probably most similar to "Walker's Area 45" or the "frontal eye field area 45" in the monkey, which has more dorsal sources of parietal input than the more ventral pVLPFC area of interest here).

This area is also differentiable from more anterior (BA 47/12) and more dorsal (46v) areas by virtue of its connectivity with the superior temporal sulcus. Classically the pVLPFC is sometimes referred to as "Broca's Area", and although it turns out that's somewhat of a misnomer, it is a (largely) fortunate one for our purposes: there's lots of detailed neuroanatomical research done on this area, both in the human and the primate.

In this light, our first problem may seem surprising: does this area exist in the monkey?

Yes is the short answer, although about 10 years of debate surround that simple answer (as stated by Gerbelli et al., "[this sector] occupies a cortical sector of a highly controversial architectonic attribution, assigned to areas 46 and 12 by Walker (1940), to areas 8 ventral and 46 by Barbas and Pandya (1989) and mostly to area 12 by Preuss and Goldman-Rakic (1991) and Romanski (2004, 2007)").

The long answer is most easily grasped visually (image from Leh, Petrides & Strafella):

As reviewed by Petrides, Cadoret & Mackey, it has been argued that human BA44 has no homologue in the monkey. Others have argued that it does, such that human BA 44 corresponds to monkey area F5, sometimes termed PMv (ventral premotor cortex - behind the arcuate sulcus), with the monkey homologue of human BA 45 lying just anterior to the arcuate. But on the basis of their own careful analysis, Petrides et al suggest that BA 44 actually lies within the arcuate sulcus in the monkey, with ventral BA6 lying behind it; BA 45 is anterior to 44. We will assume Petrides et al's view to be the correct one for the remainder of this post.

Now that we have identified where in the monkey these areas exist, it is worth covering the noteworthy differences between 44 and 45. And there is one - although perhaps only one: in terms of the presence of layer IV neurons, which are only "incipient" in 44, but well developed in area 45. Otherwise, these two areas share many features, including large pyramidal cells in deep layers III & V, the lack of a clear border between layers II vs. III, and a low cell density in layer VI. Gerbella et al., on the basis of cyto-, myelo-, and chemo-architectural studies, suggest that the relevant region (45B, although they did not report data from deep within the arcuate) can be defined solely on the basis of its extremely large outstanding layer III pyramidal cells, which are comparaitvely greater and more dense than those in layer V.

The functional significance of these laminar features may be better understood with respect to general principles of cortico-basal ganglia and cortico-thalamic projections (as described by McFarland & Haber, 2002). Layer V is reciprocally/bidirectionally connected with thalamus and represents a kind of positive feedback loop for corticothalamic processing. (A subset of these layer V neurons with bidirectional thalamic connectivity also have axon collaterals that project to the striatum). Layer I tends to be a recipient of more diverse corticothalamic projections, and thus represents a kind of "open loop" in the thalamocortical architecture. Finally, Layer III neurons tend to project preferentially to the striatum in prefrontal cortex (whereas in posterior cortex it represents a source of more local, cortico-cortical loops). MD subregions in particular may receive nonreciprocal projections from ACC and pre-SMA.

These claims, however, are not very specific to our particular region of interest. So what about the connectivity of this pVLPFC region in particular?

Human BA 44/45, aka pars opercularis and triangularis, of the human VLPFC, and its cortical/thalamic/striatal interconnectivity.

Striato-thalamic input to pVLPFC has been investigated by Tanibuchi, Kitano & Jinnai 2009 who studied precisely the area Petrides et al consider to be the monkey homologue of the human pVLPFC (check out recording site PSvc). Yet the connectivity here is somewhat surprising: this area is innervated by thalamic area MDmf/pc, which is itself innervated by the caudal area of the substantia nigra pars reitculata, as opposed to the pallidostriatal pathway that is commonly thought the dominant striatal pathway for innervating the thalamic areas that project to more dorsal regions of premotor and prefrontal cortex. This is in turn reflected in the cortical input to these pathways; as noted by Kitano, Tanibuchi & Jinnai 1998, SNr neurons with multisynaptic inhibitory input from dorsal prefrontal cortex are three times fewer than those with multisynaptic inhibitory input from ventral prefrontal cortex; conversely, dorsal prefrontal input to striatum is conveyed mainly by through GPi. Similar results were observed by Middleton & Strick 2002, and Middleton & Strick 2001, who said "Labeled neurons were found mainly in GPi after virus injections into area 46d [dorsal PFC], whereas labeled neurons were found mainly in SNpr after virus injections into area 46v [ventral PFC]."

Tanibuchi et al argued that "signals emanating from the PSv [primarily PSvc, or our pVLPFC region - CHCH], via inhibitory caudatonigral and nigrothalamic pathways, have a disinhibitory effect on thalamic neurons in the rostrolateral MD, wherefrom they may eventually return to the same cortical area as positive feedback signals." These authors further argued that this PMv/SNr circuit is "concerned with recognition of the relationship between the visual stimulus and the behavior."

But aren't GPi and SNr just interchangeable (except that maybe SNr is more involved in "oculomotor behavior" and GPi in "skeletomotor behavior")? If that were true, the observation that pVLPFC may interact rather preferentially with SNr has little functional punch. Moreover, everyone seems to write about GPi and SNr as though they're interchangeable - separated by the internal capsule by some evolutionary mishap, and the SNr simply more involved in oculomotor behavior. With respect to that latter point, I'll quote from Shin &
Sommer, 2009:

"When we began our study, the direct pathway through GPi and the indirect pathways through GPe had not been ruled out as oculomotor circuits; to our knowledge they simply had not been studied (with one exception: Kato and Hikosaka 1995)."

In fact, SNr and GPi can be differentiated in a number of ways. As extensively described by Romanelli, Esposito, Schaal and Heit, 2005, the SNr does not receive the same highly topographic input as GPi does, and as such represents a major departure from the highly topographic organization of the rest of the basal ganglia. Indeed, the SNr has been argued to be far more integrative or associative. Here I might as well just quote from Kaneda, Nambu, Tokuno & Takada 2001:

It has long been believed that the GPi and SNr belong to a single entity that is split rostrocaudally by the internal capsule (Parent 1986). In this view, the two structures are likely to play exactly the same role in the processing of information along the cortico-basal ganglia loop. However, in terms of the parallel versus convergent rules of information processing, the present work provides anatomical evidence that the mode of dealing with corticostriatal motor information from the MI and SMA through the striatopallidal and striatonigral projections is target-dependent, such that the parallel rule governs striatopallidal input distribution, whereas the convergent rule determines striatonigral input distribution. This strongly implies that the arrangement of the striatopallidal system closely reflects the organization of the corticostriatal system, while that of the striatonigral system does not. It has also been reported that the firing pattern of SNr neurons is less affected in parkinsonian monkeys than that of GPi neurons, suggesting their functional differences in motor behavior (Wichmann et al. 1999).

In other words, we can't just conflate GPi and SNr, with the exception of domain (skeletomotor vs. oculomotor). Moreover, the intrinsic organization of these structures is quite different: GPi maintains segregation [i.e., follows the "parallel" rule of Kaneda et al] whereas SNr is more convergent) AND the inputs to these regions are quite different (with GPi afferents originating from motor and dorsal prefrontal cortex, and SNr afferents originating from orbital and lateral prefrontal cortex, and perhaps pVLPFC predominantly).

As mentioned in the above Kaneda et al quote, GPi is more strongly implicated in Parkinson's and movement disorders. In contrast, the role of the SNr is widely considered to be more attentional, associative or sensory in nature. For example, it is more often implicated in so-called "sensory gating" than "motor gating" of the kind commonly thought to characterize dorsal prefrontal cortex. For example, as compared to GPi, SNr has an abundance of visual (but not merely oculomotor) responses and a relative paucity of reward-related responses.

Perhaps the most compelling demonstration of this difference in function is Wichman et al 1999, who showed that administration of the toxin MPTP (which kills dopaminergic cells in the substantia nigra, which are concentrated in the pars compacta segment) had actually less of an effect on substantia nigra pars reticulata firing than on GPi firing! This is surprising given that SNr neurons are thought to be modulated directly by the SNc neurons, and yet the effects are far more pronounced in the structure on the other side of the internal capsule, the GPi.

Summary: Cytoarchitectural and Connectivity of pVLPFC

pVLPFC is preferentially interconnected with the MDmf nucleus of the thalamus and contains large layer V neurons, which seem in large part to support direct corticothalamocortical "positive feedback" loops in prefrontal cortex. pVLPFC also contains large layer III pyramidal cells which project, via caudo-nigro-thalamic projections, back to the MDmf, through the substantia nigra pars reticulata. This connectivity pattern is distinct from other areas of PFC, notably from the more dorsal sector with which pVLPFC is sometimes lumped, insofar as those more dorsal prefrontal regions may more strongly interact with the other major output nucleus of the basal ganglia - the internal segment of the globus pallidus. The functional significance of this distinction is not yet perfectly clear, but does not solely reflect specializations for oculomotor vs. skeletomotor behavior in the SNr and GPi respectively. Instead, it appears that the nature of information processing in the SNr is substantially more associative or convergent than the more segregated somato/corticotopic that occurs in the GPi; it may also be more sensory (or, at least visual) in nature than motoric. This claim is paralleled by a reduced involvement of the SNr in Parkinsonian phenomena relative to the GPi, and the SNr's comparatively greater involvement in phenomena like sensory gating and visual processing.

developinginte… Thu, 11/17/2011 - 06:43

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cognitive neuroscience

Comparative Psychology

Bu talebi de Parkinsonian olaylarÄ±n gÃ¶reli olarak GPI SNr azaltÄ±lmÄ±Å bir katÄ±lÄ±mÄ± ve duyusal Ã§oÄunluÄuna ve gÃ¶rsel iÅleme gibi olaylarÄ±n SNr'Ä±n nispeten daha fazla katÄ±lÄ±mÄ± paralellik.

From the Archives: What Can 3D Movies Teach Us About How Ants Smell?

jgoldman — Thu, 23 Jun 2011 07:30:00 +0000

From the Archives: What Can 3D Movies Teach Us About How Ants Smell?

A version of this post was originally published on my Wordpress blog on March 15, 2010. Click the archives image to see the original post.

Most animals, at some point in their day-to-day lives, face the same problem. After they've gone out in search of food, they need to find their way home. But some of the places where these critters live lack any real visual landmarks - like the open ocean or wide expanses of desert. Instead of relying on vision, some animals have developed the ability to use olfactory (scent-related) cues to aid in navigation. Seabirds can detect subtle changes in the smell of plankton in the air over hundreds of kilometers, and pigeons seem to use olfactory cues for finding their way home. It is known that some insects follow their noses (so to speak) to find food or a suitable mate. But Kathrin Steck, Marcus Knaden, and Bill S. Hansson of the Max-Planck Institute for Chemical Ecology wondered if the desert ants of Tunisia might use olfactory cues for homing.

It turns out that despite the visually featureless landscape, the salt pans of Tunisia actually have scent-related features. Variations in soil composition, breaks in the salt, and dead plants, all contribute different odors to the landscape. Do ants use the olfactory information in finding their way back to the entrance of their nests?

The researchers isolated four odor-producing compounds from various objects found in the vicinity of the ants nest. The first order of business was to verify that the odors were not particularly repulsive or attractive to the ants. The ants were then trained to forage for food in an 8 meter long trough, with the end of the trough that had been baited with food always downwind from the nest's entrance. The experimenters applied one of the odors to the floor at the nest entrance, and re-applied the odor every 20 minutes, to ensure that the scent remained stable over time.

Would the ants learn to associate the specific odor with their nests? They tested them in troughs that contained (1) the same odor, (2) a different odor, (3) a mixture of four odors including the trained one, and (4) no odor at all.

Indeed, the ants learned to associate the specific odor they had been trained on with the nest entrance. They did the best under condition 1. And, they were able to pick out the trained odor from among the collection of four odors in the third condition. They were slightly less successful under condition 3 than condition 1, but way more successful than under conditions 2 or 4. In this figure, the trained odor condition is on the top, then the four odors condition, then the control condition is on the bottom. Each one is statistically significantly different from the others. The closer to the zero-point, the closer to home the ants wound up.

Pretty cool. But we're not done yet. Oh no. First we put ants on stilts. Then we cut off their legs to create stumps. We blindfolded them and trapped them under boxes. But we have not yet antennectomized the ants. Until now.

What's an antennectomy, you ask? I'll tell you. Ants have two antennae. If you cut one (or both) of them off, you have performed an antennectomy. What are antennae used for? Smelling, of course.

So, think of it as a nose job for an ant.

Its a good thing ants don't care much about their appearance. So much harder to perform a nose job if you've got two independent organs. "Doc, my one antenna is LONGER and THICKER than the other, and it's HUMILIATING!"

So they trained the ants, as before, to forage in an open trough. One of four different odors was placed in each corner of an imaginary square adjacent to the nest entrance (in the figures below, this is represented by the four different letters). Since ants do not antennate the ground while walking, we can be sure that the ants are using their antennae for smell and not for taste.

The food was always aligned downwind from the nest as before, and the nest was never located at a spot of the highest concentration of an odor. Therefore the nest was gradient-specific, not odor-specific. Would the ants be able to use an odor gradient (as opposed to a single odor, as in the previous study) to find the nest? Do they perceive a sort of olfactory landscape? Are unilaterally antennectomized ants (ants with one antenna removed) at any disadvantage compared to intact ants?

In this figure, the little antenna represents the antennectomized ants. The other conditions represent intact ants. The left three conditions represent odor gradients; and the right two conditions are odors at a single spot ("point-source odors" as in the previous study). Going from left to right:
Condition 1: Intact ants on the training array did really well.
Condition 2: Intact ants with a right-left reversed testing array performed significantly worse than in training. This suggests that ants don't just detect the overall array, but are sensitive to the position and strength of the odors within the array. That is, they track which odors are coming from the right and which from the left.
Condition 3: Antennectomized ants traveled five times longer than intact ants in condition 1, and did significantly worse.
Condition 4: This was basically a replication of the previous study. Intact ants trained to associate the nest with a single point source odor performed well. There was no significant difference between this condition and condition 1.
Condition 5: Antennectomized ants, when trained to associate the nest with a single point source odor performed well also! There wasn't a statistically significant difference between these ants and the intact ants, when it came to point-source odors.

Taken together, this means that ants that have one antenna removed aren't completely deprived of using odor cues (as condition 5 indicates). However, they are unable to use odor gradients in an array to locate the nest, as in condition 3. This suggests that ants smell in stereo.

What does it mean to smell in stereo? Well, humans smell in stereo thanks to our two nostrils, but this is hard to perceive. But humans also see in stereo, and this is probably a little more intuitive. Each of your eyes detects a slightly different image, and the visual cortex uses the slight difference between the two retinal images in order to construct a three-dimensional scene in your mind. Close one of your eyes, and you'll realize that you have no real depth perception to speak of. Humans also hear in stereo, thanks to our two ears. If you covered one of your ears, you would find it very hard to determine the location of a sound. Thanks to the fact that sound waves reach each of your ears at slightly different times, your brain is able to figure out where in space a sound is coming from.

This is, incidentally, what filmmakers capitalize upon to make 3D movies. The projected image is two-dimensional, obviously. However, the projected image is composed of two slightly different versions of the same image. In old school 3D movies, the two images were colorized differently; one lens of the glasses filtered out red light, and the other lens filtered out blue light. The resulting images were projected onto your retina, and your brain put the two images together to construct a 3D image. New-school 3D movies work the same way, but are based on the light's polarity, rather than color.

In much the same way, the two antennae of the desert ant (or your two nostrils) each have a slightly different olfactory "viewpoint" of the same olfactory "scene." If you remove the input to one of your eyes, you don't completely lose vision, but you lose the ability to perceive three-dimensional depth. Likewise, if you antennectomize the desert ant, it doesn't completely lose olfaction, but it loses the ability to organize olfactory cues in three dimensions.

Steck, K., Hansson, B., & Knaden, M. (2009). Smells like home: Desert ants, Cataglyphis fortis, use olfactory landmarks to pinpoint the nest Frontiers in Zoology, 6 (1). DOI: 10.1186/1742-9994-6-5

Steck, K., Knaden, M., & Hansson, B. (2010). Do desert ants smell the scenery in stereo? Animal Behaviour. DOI: 10.1016/j.anbehav.2010.01.011

jgoldman Thu, 06/23/2011 - 03:30

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ant

Comparative Psychology

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Brain and Behavior

Fascinating!

If you pay attention and if the smell isn't yet filling the air, you'll notice that you can tell whence an odour is coming.

Fido Might Not Know What You Do and Do Not See

jgoldman — Thu, 16 Jun 2011 08:00:00 +0000

Fido Might Not Know What You Do and Do Not See

You've probably had a conversation that goes something like this:
Person A: "My dog is sooooo amazing!"
You: "I mean, dogs are awesome and all, but what's so amazing about this particular dog?"
Person A: "He just understands me. It's like he knows what I'm thinking and what I need."
You: "Do you think he's just maybe responding contingently do your overt displays of emotion?"
Person A: "Listen, man, I'm telling you: my dog can read my mind!"

No matter on which side of this sort of argument you tend to fall, the question of whether or not domestic dogs can read human minds is an interesting and important one. More specifically, do dogs have a theory of mind? Can they take the perspective of a human?

Dogs show a wide range of "human-like" social behaviors. They respond appropriately to human body language and to verbal commands, and are capable of facilitating joint attention with humans. It some cases, their social skills, at least in terms of communication with humans, surpasses those even of chimpanzees.

Also, impressively, domestic dogs tend to perform particularly well in theory of mind experiments. The problem is that the experimental participants in these studies could potentially be responding to other sorts of contextual social or environmental cues when succeeding at theory of mind tasks, rather than relying on theory of mind skills per se. Ever the empiricists, some also argue that associative learning, rather then an innate theory of mind module, could account for dogs' apparent theory of mind skills. If either of these sorts of arguments were indeed the case, then theory of mind would not strictly be necessary to explain these sorts of complex behaviors.

The best sorts of experimental designs to use in non-human animal theory of mind tasks derive from what I call the "Hare Task." The Hare Task was originally designed for chimpanzees, and is in essence a food competition task. Two chimpanzees, one dominant and one subordinate, are placed at opposite ends of the testing area. Between them are two barriers, one clear (like a window), and one opaque. Just behind each of the barriers, on the side of the subordinate chimp, is a piece of food. In typical interactions, the dominant chimp always has first access to the food. However, the dominant individual can only see the food behind the clear barrier, while the subordinate individual can see both pieces of food.

The set-up looks something like this (source):

The idea is that if the subordinate chimpanzee has a theory of mind - if he (1) knows what the dominant individual does and does not see, and (2) assumes that the behavior of the dominant individual will be consistent with that knowledge - then the subordinate chimp should immediately retrieve the food behind the opaque barrier, and leave the food behind the clear barrier to the dominant chimp.

This sort of task can be easily modified to address slightly different questions for different animals, and recently in the journal Learning and Behavior, psychological scientist Monique Udell and colleagues from the University of Florida, Gainesville, have modified the Hare task to ask if domestic dogs can take the visual perspective of humans. Given that domestic dogs tend to do well on theory of mind tasks, Udell wanted to know if their success emerges due to a theory of mind, or whether their success can be explained by learning processes (such as classical or operant conditioning).

More specifically, some have argued that human-like social skills in dogs are the result of selection through the process of domestication, even if as a correlated by-product of the selection for or against something else. If these social skills are the result of domestication, then they are not simply the result of experience or learning. If this is true, Udell reasoned, then "all healthy populations of domestic dogs should be expected to outperform non-domesticated canids on human attentional-state tasks. Furthermore, this should hold true independent of the age, condition, home environment, or experience level of the dog under test."

In order to investigate this question, Udell tested the ability of three different groups of canids, each of which varied on evolutionary origins or developmental experiments: pet dogs, shelter dogs, and human-reared wolves. All pets dogs were brought into the lab by their owners. The researchers were careful to exclude any shelter dogs that were owner-surrenders, and only tested strays who were comfortable around humans, but clearly had significantly fewer social experiences. The human-reared wolves were from Wolf Park, in Battle Ground, Indiana.

If dogs' success at theory of mind tasks is the result of domestication, then both groups of dogs should outperform wolves, regardless of experience. However, if dogs' success is the result of experience or learning, then the pet dogs should outperform the shelter dogs, and the human-reared wolves might outperform the shelter dogs as well.

In each of four conditions in this experiment, the dog or wolf was allowed to approach one of two researchers holding a piece of food in her hand. One of the researchers was designated the "seer," while the second one always had her vision obstructed ("blind"). The "blind" researcher could be blind in one of four ways: back turned to the subject, holding a book in front of her face, holding a camera in front of her eyes, or holding a bucket over her head.

In each trial, the wolf or dog was kept 6 meters away from either of the two researchers by a third research assistant, with his or her back to the researchers. Then, in unison, both researchers would call the name of the dog or wolf (or, for the shelter dog, they'd say something like "here, puppy!"). The question was which researcher would the dog or wolf approach? Once the wolf or dog stayed within 1 meter of the chosen researcher for three seconds, the trial was concluded. In addition, the "seer" had to visually track the wolf or dog throughout the trial so that eye-contact could be initiated. If the subject approached the "seer," he or she was rewarded with the food; if the subject approached the "blind," even though she always held a piece of food in her hand, the subject was never rewarded.nd on every trial. Each dog participated in only two of the four possible conditions, though the wolves participated in all four experimental conditions (though they were distributed over the course of a year, to minimize the possibility of within-experiment learning). Altogether, each individual completed a total of ten trials.

Pet dogs and wolves had the best performance, with median performance levels of 9 out of 10 trials correct. Shelter dogs had the worst performance, with median performance levels of 7 out of 10 trials correct. For one condition, all three groups of canids performed significantly above chance: the back-turned condition. The results for the more nuanced conditions were, understandbly, more variable. For the book condition, pet dogs performed above chance, and significantly outperformed the shelter dogs and the wolves. While pet dogs performed above chance in the bucket condition, there was no significant group difference, and all three groups did similarly poor in the camera condition (no group performed, on average, above chance levels).

Udell and colleagues' interpretation of the results is pretty straightforward, and is quite reasonable given the data (emphasis is mine):

The hypothesis that domestication is sufficient for dogs to engage in perspective taking is rendered problematic by the observation that dogs' performance on these tests depends on the type of occluder used and on the life conditions of the canid. Furthermore, the success of wolves on one condition demonstrates that domestication is not essential for above-chance performance under all conditions. The alternative position is that domestic dogs and other socialized canids are not taking the mental perspective of the seeing or blind individual, but instead making a discriminative choice based on past reinforcement histories, in which certain human actions or orientations served as predictors of reinforcement upon approach. This hypothesis is consistent with the patterns of success and failure found in this study.

They reason that all individuals in the study, whether pet dogs, shelter dogs, or human-reared wolves, have experience approach individuals from the front or from the back, and all would have been equally likely to learn that it is statistically more likely to receive food from a human who is facing them than one whose back is to them. They argue that pet dogs would have had experience with humans reading books, and were therefore successful in that condition, while shelter dogs and wolves presumably had less or even no experience with book-reading humans on which to base their behavior. They explain the failure of even the pet dogs to respond appropriately in the camera condition to the possibility that the camera was simply too small of a visual barrier, making it less salient. To their credit, they also note that "on the other hand, humans can and do see through the lens of a camera and may even actively reinforce dogs or wolves for orienting toward them if they are the subject of the photograph. Therefore, the failure to discriminate between experimenters in this condition might even be considered the correct response." When it comes to the bucket condition, it might seem surprising that even the pet dogs were unable to perform accurately. The researchers argue that each of the three groups of canids were unlikely to have had any experience interaction with humans who had buckets over their heads, and, as with the book, were unlikely to have learned the appropriate behavioral response to that stimulus.

The researchers conclude that domestication is not necessary, nor sufficient, to explain the performance of domestic dogs on theory of mind tasks. This is not all that surprising to me, though I would not take the position of the empiricist, and argue that their performance is more likely the result of learning. Rather, I am simply unsurprised that wolves have at least some rudimentary perspective-taking ability. Domestic dogs' theory of mind is probably just a little bit sharper, or a little bit more fine-tuned due to experience, than that of wolves.

Further, Udell and colleagues hypothesize that "dogs' ability to follow human actions stems from a willingness to accept humans as social companions, acquired early in [development], combined with conditioning to follow the limbs and actions of humans to acquire reinforcement." My main problem with this line of reasoning is that this experiment doesn't actually involve the movement of limbs, or any human actions. The only change in the body-state of the human researchers in the experiment is the tracking of the dog or wolf by the "seer," so I'm not clear where any sort of action-related conditioning could enter into the dogs' mental processing in the first place.

So, I suppose I'm just unconvinced with the larger argument put forth in this paper. Rather, I tend to agree with the notion that domestication has allowed for dogs to engage socially with humans in a way that wolves are not incapable of, but for which they are relatively unprepared. The fact that human-reared wolves had at least minimal success in this experiment does not surprise me, especially since they're human-reared. The interesting finding, however, is the relative underperformance of pet dogs in the bucket and camera conditions: this is something, I think, that warrants further investigation. Why does performance in this task vary based on how the eyes of a human are occluded? It stands to reason that it ought to vary based on whether a human's eyes are occluded or not.

It is also possible that some of the failures of the dogs and wolves in this experiment is simply due to the human presence. I'd be interested in seeing what would happen if the dogs and wolves were placed in a more competitive context, similar to the original Hare task. And, while we're at it, how about comparing domesticated and undomesticated Siberian foxes? Now there are two populations of critters with highly controlled experiences, and precisely defined genetic relatedness.

Udell MA, Dorey NR, & Wynne CD (2011). Can your dog read your mind? Understanding the causes of canine perspective taking. Learning & behavior PMID: 21643852

Hare B, Call J, & Tomasello M (2001). Do chimpanzees know what conspecifics know? Animal behaviour, 61 (1), 139-151 PMID: 11170704

For more:
Wolves Are Smart, But Dogs Look Back
How Specific Are The Social Skills of Dogs?
Did Dogs Get Their Social Intelligence By Accident?

Dog photo by the author.

jgoldman Thu, 06/16/2011 - 04:00

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"The problem is that the experimental participants in these studies could potentially be responding to other sorts of contextual social or environmental cues when succeeding at theory of mind tasks, rather than relying on theory of mind skills per se."

In my humble opinion, this is also a problem in human theory of mind;
humans theory of mind could be a response to contextual and environmental cues, addition of semantic conceptualisations and cultural inheritance of converged and integrated introspective information. i.e. The perspective taking could well be something we learned to know or appreciate by information accumulation over many generations.

"the notion that domestication has allowed for dogs to engage socially with humans in a way that wolves are not incapable of, but for which they are relatively unprepared."

Wouldn't the evolution of dogs offer a clue for this too? Where domestication would have envolved the wolves who were least reluctant to engage in contact with humans, thus splitting the population in these distict directions of social preferance. Resulting in wolves as primarily succesfull outside human populations and dogs primarily succesfull within them.

It's refreshing to see you bucking an evident trend in what's increasingly becoming an inaptly named science blogs. Thanks or reporting on some interesting science and doing it well.

The type of occlusion thing doesn't surprise me. It's pretty commonly understood in dog training circles that dogs are fantastic at learning specific things and average to poor at learning general things. A common example of this is the puppy that is perfectly behaved at obedience classes, and completely untrained at home -- context specificity needs to be actively trained out.

The generalization "covered eyes can't see me" is, in my opinion, just too broad for a dog to understand. I'm sure the behavior "ignore people with covered eyes" could be trained, but I think it would be pretty challenging.

Did anyone take note which way the wind was blowing? If canines do have a theory of mind, they may assume humans downwind of them know they are there, especially the less experienced ones.
I'm glad they realized the camera was not really a good obstacle test, though. Pets are always being photographed and often take an interest in the camera.
How close were the animals to the people? How different does a bucket look from a hat, from a dog's perspective? Terry Pratchett wrote a dog looking up at a human basically sees a wall with a pair of nostrils up top.
In short, the description of the tests make me question how good the experimenters are at forming a theory of *dog* mind.

Seems like the Hare test in its original form is a very good experiment. The dog version though is messy. Dogs have many possible motivations, praise, curiosity (of a sort), food etc. Are these dogs/strays/wolves all primarily food or praise or otherwise motivated? The subjects may have other preferences for male or female humans, high or low pitched voices, perfume/cologne or lack thereof. Also, the interval between testing, shelter dogs go back to the shelter (I assume) though not having a history of ownership as a pet, surely living in the shelter and no longer scavenging for food and randomly interacting with humans would change the dogs learned behavior significantly.

Of course man.All dogs normally listen's to the one who made it gro and had it for a long time.Even some dogs read the human's mind clearly if it's a clever dog.

Is Pedagogy Specific to Humans? Teaching in the Animal World

jgoldman — Thu, 12 May 2011 08:30:00 +0000

Is Pedagogy Specific to Humans? Teaching in the Animal World

Human infants have one important job during the first years of life, and that is to learn about the world and their culture from their parents and other caregivers. But what is learning? I've previously written that Hungarian developmental psychologists Gergely and Csibra have defined learning as the acquisition of new, generalizable knowledge that can later be used within a new context. Further, they have posited that evolution has prepared humans to learn generalizable knowledge from their caregivers. They proposed an elegant hypothesis: that a specialized innate pedagogy mechanism - called the pedagogical learning stance - is in place that allows an infant to retain generic information. This means that they are able to learn information in a given instructional setting, that they can later apply to wide range of potential new situations.

This sort of cognitive system requires at least three things. First, the learner must understand the communicative intent of the teacher via ostensive cues. One such cue for humans is the use (by a parent or teacher) of infant-directed speech, or baby-talk. Second, the teacher and learner must be able to jointly use referential signals, such as eyegaze and pointing, in order to facilitate joint attention. Third, the learner must be able to understand the information content of the pedagogical interaction; that is, they must realize that they are getting relevant information for the given task.

There is good evidence that humans do, indeed, have innate pedagogy. But Gergely and Csibra take their claim a bit further. They claim: (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 remaining posts in this series on pedagogy will deal separately with each of these three claims. Today, we'll ask if pedagogy is human-specific, or if it is possible that it is shared with other animals.

Pedagogy is, in its simplest form, a form of social learning that occurs via communication between two (or more) individuals, which has as its outcome the transfer of knowledge or skills. There are abundant cases of both social learning and of communication in non-human animals, of course. Are there ever any cases where social learning and communication combine in any other species that allows for knowledge transfer similar to human teaching? The short answer is: no. But let's examine this in some more depth.

One question we might ask is whether there are any forms of animal communication that go beyond the providing of episodic information (related to the here-and-now, immediate context) and approach the transfer of generalizable information? Certainly, there are cases of non-human animal signals that are referential, inasmuch as they are meant to facilitate joint attention on an external stimulus or event, even if that stimulus or event is not within view. For example, various animals use alarm calls that refer to predators or to food, or ones that are used for other social purposes, such as to recruit group members for an antagonistic interaction with another individual. Bees use elaborate "dances" to indicate the location and quantity of food available in a given location. And some animals, such as howler monkeys, even have predator-specific calls, such as "aerial predator," like the one they use for the fearsome harpy eagle.

However, these signals don't identify something like "aerial predator," they actually transmit a message more like "aerial predator approaching!" There is no alarm call for "hey, did you see how I totally beat up that aerial predator?" or "the aerial predator is approaching from the northeast but his vision is based on movement so remain still," or even "aerial predator gone, the coast is clear." More important for the question of pedagogy, there is no alarm call that goes something like, "aerial predators tend to hunt during the daytime." It is in this sense that communication among non-human animals only transmits episodic information, and not generic information.

In developing this argument, Gergely and Csibra are quick to point out that the absence of generic information transmission among non-human animals does not mean that non-human animals can not learn, in a more general way, from episodic information in the first place. For example, using a simple statistical learning mechanism, an infant bird could learn how to find food by learning a correlation between a certain chirp made by its mother, certain features of her location, and the resulting feast. In this case, however, the generic information (where to find food) comes not from the communicative interaction, per se, but from a learning process wholly contained within the infant bird (even if the learning process is initiated by a response to a food call).

A promising example of natural pedagogy in non-human animals might have been the meerkat. Meerkats hunt and eat scorpions, which are extremely dangerous. It is really important for a juvenile meerkat to learn how to safely hunt and consume a scorpion, because just one mistake could prove fatal. What adult meerkats do is they provide the juveniles over time with scorpions, beginning with dead ones with stingers removed, then dead ones with the stingers intact, and finally living and lethal scorpions. The progression from safe to more and more dangerous scorpions is determined according to the age and skills of the juvenile meerkat. For example, in the stage where the adult provides a living scorpion with stinger removed, the juvenile can successfully learn how to kill a scorpion without the danger of dying. Two important criteria for teaching are met here: first, the teacher adjusts the curriculum (and therefore, his or her behavior) as the learner progresses and gains knowledge. This is strong indication of pedagogy. However, there is no explicit communication involved in this process. In fact, this process more resembles a teaching strategy termed "scaffolding" by developmental psychologists, than the sort of natural pedagogy that Gergely and Csibra have hypothesized. One other important distinction between pedagogy and this case is that teaching in meerkats is domain specific. This means that scorpion eating is the only form of instructional learning in meerkats. Pedagogy in humans, on the other hand, is domain general: humans can teach and learn just about anything.

Another promising case of teaching in non-human animals seemed to be tandem-running ants (Temnothorax albipennis). This occurs when one individual knows the location of food, and he communicates that information to a second individual, who then learns that information. When Nigel Franks and Tom Richardson published this finding in Nature, they announced that, "tandem running is an example of teaching, to our knowledge the first in a non-human animal." Even if this is not natural pedagogy, as Gergely and Csibra would argue, it is a remarkable example of a simpler form of teaching. Specifically, the leader in the pair not only directs the follower to the food, but modifies its behavior based on the behavior of the learner. For example, it slows down or stops in order to allow the learner to memorize the path, and if for some reason the teaching is interrupted, the leader will wait for the learner to return before commencing with the instruction again. The leader takes the front position, and requires consistent tapping on his rear end from the antennae of the learner in order to continue the lesson. While this form of teaching does, therefore, include bidirectional signals and information transfer, the information is decidedly episodic in nature, and not generalizable. The information gained by the learner is how to get from specific location A to specific location B, and not how to find food more generally. And, as with the meerkats, this teaching is domain-specific. There is no evidence yet that this sort of bidirectional communication is used by ants for anything other than indicating the location of food.

In general, the evidence is mounting that natural pedagogy is unique to humans. That does not mean that it is impossible that we might one day discover natural pedagogy in non-human animals. Indeed, there are some examples that come tantalizingly close. Critically, however, there are no known teaching processes in non-human primates, beyond simple learning mechanisms such as imitation and emulation.

Therefore, if pedagogy is absent in non-human primates, and ends up being present in some other animal, this would more likely be a case of convergent, rather than homologous, evolution. This would be consistent with Gergely and Csibra's hypothesis. With respect to the possibility for non-human pedagogy, they write:

If this is proven, it will show that natural pedagogy is not human-specific. Nevertheless, this would not disconfirm our hypothesis that the cognitive systems that enable pedagogical knowledge transmission in humans represent a hominin adaptation, because analogous adaptations can emerge independently in distinct lineages. Crucially, no convincing example of teaching has been found in non-human apes or other primates. Thus, if natural pedagogy is an evolutionary adaptation, it must have emerged in the hominin lineage.

At least provisionally, the conclusion can be reasonably drawn that natural pedagogy is a uniquely human cognitive mechanism. Count this is one point in favor of Gergely and Csibra's pedagogy-as-adaptation argument. Next, we will consider whether natural pedagogy is universal among humans.

The Pedagogy Series
Part 1: Perseverating on Perseverative Error: What Does The "A-not-B Error" Really Tell Us About Infant Cognition?
Part 2: Are Infants Born Prepared For Learning? The Case for Natural Pedagogy

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"
Social Cognition in a Non-Social Reptile? Gaze-Following in Red-Footed Tortoises

For more on animal communication:
Robot Lizard Push-ups
To Hear A Mockingbird: The Plight of the Iguana
Hands Off My Bone!
Giant Birds and Terrified Monkeys
Elephants Say "Bee-ware!"

Csibra G, & Gergely G (2011). Natural pedagogy as evolutionary adaptation. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 366 (1567), 1149-57 PMID: 21357237

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

Boston Common ducks: Flickr/sfgamchick
Harpy eagle: Flickr/ZakVTA
Meerkat: Flickr/Andy2580

jgoldman Thu, 05/12/2011 - 04:30

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Life Sciences

Nicely summarized. I wonder if the point made, "natural pedagogy is a uniquely human cognitive mechanism", is linked with the cognitive functions of complex language unique to humans - particularly the phenomena of synaesthesia?

Michael

I wonder if there isn't a subtle bias which says: This is how humans learn, we can't find another species that learns in exactly the same way, therefore there is no innate learning/teaching ability outside our species. The definition of learning guarantees the negative conclusion. I think an important question is, Do other animals need our type of learning? The destruction of our planet's systems by humans does not speak well for our learning/teaching abilities. Humans do not learn well at all! We keep on repeating obvious mistakes. We have managed to save our asses so far by ruthless exploitation of resources, but will we ever learn?

A possible example of chimp pedagogy is shown in part of this clip around the 2:15 mark. Your thoughts?

http://www.youtube.com/watch?v=AElmAJH2G00&feature=channel_video_title

To reply quickly to bomoore: I don't think that Jason is suggesting in any way some sort of superiority of the way humans learn over that of other animals. Animals undoubtedly require different types of learning, different types of experiencing and communicating things about themselves and their surroundings than we do. He's not saying here that animals are lesser, so to speak, for having different methods of learning.

That said, I've wondered a bit on the idea of the self-contained learning, like the baby bird mentioned above. Is it possible, more likely even, that instances that appear to be non-communicative may simply be nonvocal?

Great post, by the way.

I'm not a "squishy" science person, but a geologist: I would say that 'mind' is an individual organism's reaction to the environment, but 'culture' is an individual's or group's interaction with the environment. This grants mind and culture to all forms of life; learning would be included within mind and culture. Geology encourages a continuum of qualities across a large-scale concept of earth and life.

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.

Sleepy or Empathetic: What Does Yawning Mean?

jgoldman — Wed, 06 Apr 2011 15:01:00 +0000

Sleepy or Empathetic: What Does Yawning Mean?

You know that old phrase, "monkey see, monkey do"? Well, there might be something to it, except that chimpanzees aren't monkeys. (Sadly, "ape see, ape do" just doesn't have the same ring to it.) A new paper published today in PLoS ONE has found evidence that chimpanzees have contagious yawning - that is, they can "catch" yawns from watching other chimpanzees yawning - but (and here's the interesting part) only when the chimp that they're watching is a friend.

At first, scientists thought that contagious yawning was the result of a releasing mechanism - in other words, seeing someone yawn flips the yawning-switch in the brain, and that makes you yawn. Others proposed that yawning was a mechanism designed to keep the brain cool. But it actually turns out that there is a correlation between the susceptibility for contagious yawning and self-reported empathy. Humans who performed better at theory of mind tasks (a cognitive building block required for empathy) also yawn contagiously more often (PDF). And two conditions that are associated with a distinct lack of empathy are also associated with reduced or absent contagious yawning: schizotypy and autism.

So far, contagious yawning has been observed in five mammals: humans, chimpanzees, stumptail macaques, gelada baboons, and domesticated dogs, though the interpretation of the data has been inconsistent. There is still no consensus on the function of contagious yawning, or even whether it exists in the first place.

But now, Matthew W. Campbell and Frans de Waal of the Yerkes National Primate Research Center at Emory University have proposed a more nuanced view of contagious yawning. They wondered if social group membership could affect the transmission of a contagious yawn. After all, if empathy is indeed the thing underlying contagious yawning, then contagious yawning should show many of the same behavioral signatures that empathy itself does. For example, it is known that certain parts of the brain (the anterior cingulate and the anterior insula) activate both when people experience pain as well as when another person experiences pain (other parts of the brain only activate in response to personal pain, not to others' pain). From this data, researchers suggested that humans are able to share the emotional aspects of pain, but not the physical aspects of pain, with others. This, of course, is the basis for empathy. But additional fMRI studies have further refined these findings: activity in the anterior cingulate is greater in response to watching an in-group member experience pain than in response to the pain of an out-group member. So if contagious yawning reflects empathy, and empathy varies on the basis of social status, then it is possible that contagious yawning will vary on the basis of social status as well.

Twenty three adult chimpanzees (Pan troglodytes), ranging in age from 10 to 46 years, from two different social groups were tested. Both groups lived in large outside enclosures with indoor sleeping quarters. The two groups were completely isolated from eachother. Since chimpanzees are highly territorial and overtly aggressive towards other groups, it is certain that members of the same social group are considered part of the in-group, and strangers are automatically outsiders.

Campbell and de Waal recorded videos of chimpanzees while they were yawning to use as experimental stimuli. The videos were edited down to just nine seconds each and were shown to the chimps on an iPod touch. It was expected that they would yawn more when shown videos of group members yawning than when shown videos of strangers yawning. They were also shown videos of chimpanzees doing other things, as a control condition. In this video, Tara, an adult female, yawns while watching a video of another chimp from her social group yawning on the iPod touch.

The chimanzees indeed yawned more often after watching videos of an ingroup chimp yawning compared with the ingroup control videos. In addition, they yawned more in response to the ingroup yawn videos than the outgroup yawn videos. The response to the outgroup yawn videos was no different from the response to the outgroup control videos. Also, there were no gender differences: males yawned in response to ingroup yawn videos as often as the females did.

It is possible that this response pattern could be the result of differences in attention, rather than underlying empathy, though. In other words, perhaps the chimps were simply paying more attention to the videos of their buddies than the videos of the strangers. If they had paid more attention to the outgroup members, the argument goes, then perhaps they would have yawned more as well when watching those videos. It turned out, however, that the chimps actually paid more attention to both types of outgroup videos. Despite that, they still yawned more in response to the ingroup yawn videos.

Taken together, this provides strong evidence that empathy does underlie contagious yawning, and that contagious yawning is dependent on social group membership. Given that, it is therefore unclear why humans and dogs do yawn after watching strangers or outgroup members yawn. Since all members of a chimpanzee community know eachother, not only are they members of the same group, but they are all familiar with eachother. Campbell and de Waal speculate that humans, at some point in our evolution, may have evolved the ability to consider strangers, despite their unfamiliarity, as ingroup members. If this was the case, then strangers would not automatically be considered outgroup members, as they are with chimpanzees. In order to serve as successful pets, domesticated dogs must also be able to comfortably interact with human strangers as well as with other dogs. It is possible that the selection process of domestication has allowed dogs the possibility of dissociating familiarity from group membership, as we have.

Given the potential relationship between contagious yawning, empathy, and the ingroup bias, it would be interesting to extend this research to bonobos, domestic dogs, and humans. If this line of research bears out, contagious yawning could serve as a method for better investigating the social and emotional bonds among individuals. Campbell and de Waal suggest that understanding how and why chimpanzees alternate between empathy and aggression can help us understand our own human social emotions. Indeed, humans could certainly stand to have a little more empathy towards social outsiders.

Chimp photo via Flickr user Pelican.

Matthew W. Campbell, & Frans B. M. de Waal (2011). Ingroup-Outgroup Bias in Contagious Yawning by Chimpanzees Supports Link to Empathy PLoS ONE, 6 (4) : 10.1371/journal.pone.0018283

For more on contagious yawning:
Yawn yawn yawn yawn yawn! Contagious Yawn!
Yawning Together

For more on chimpanzees:
Digitizing Jane Goodall's Legacy at Duke
The Fate of the Alamogordo Chimps
A Bonobo in the Hand or Two Chimps in the Bush?
Chimpanzee Curiosity
Gratitude: Uniquely Human or Shared With Animals?

jgoldman Wed, 04/06/2011 - 11:01

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Maybe attention has an inverse relationship with yawning, i.e. the more attention you are paying the less the chance of you yawning?

Thanks for this post. Could you clarify for me why the researchers think (and maybe you think too?) that it's EMPATHY and not just SOCIAL FAMILIARITY or even EMOTIONAL CONNECTION that's being measured here? Isn't empathy different than these other two? I think I'm still missing something.

It seems to me that any action that involves the showing of teeth might be interpreted as a show of power. Even smiling, for that matter. I tend to think of yawning as a signal saying "I might be tired, but remember these ? My teeth, I mean. I'm still a formidable foe".

It would be interesting to see if bonobos are similar, as I understand they build their social groups differently ? Personally, I'm somewhat disgusted by the way chimps and humans alike are so aggressive and power-hungry :-( but that's another subject, I guess.

Barbara (@2): The authors write:
"In this article, we use the definition of empathy supplied by Preston & de Waal, in which empathy is a term for a broad category of resonant emotional responses comprising a continuum from basic forms, such as emotional contagion, to complex forms, such as cognitive empathy."

So that's part of the answer - they're using empathy, broadly construed.

Erling (@3): It would, indeed, be interesting to see how bonobos respond to this sort of task. I had the same thought, myself.

I think we may have just found a piece of the mechanism that explains certain types of bigotry that are not predicated on overtly observable characteristics (e.g. religious bigotry and homophobia, as distinct from racism). Bear with me on this:

Yawning can be considered as one instance within a larger category of "behaviors that convey internal state data to others" or "internal state carriers" for short. By "internal state data" I mean information about the emotional state, visceral condition, etc., of an individual. Another example would be "tone of voice," another would be "facial expression," etc.

Operationalize "empathy" as "the ability of a person to produce behaviors including verbal descriptions, that accurately (as determined by blind matching) reflect the internal state of another person." (I tried this in grad school using verbal output only, and the results were inconclusive at best. Nonetheless I believe the underlying idea deserves further examination; yes that belief is open to criticism, etc.)

Assume that Jason's hypothesis is supported: that yawning in humans is indicative of a tendency toward empathizing with other humans in general, rather than only empathizing with one's specific clan or tribe or similar in-group. Assume further that yawning provides both other-feedback ("he yawned with I yawned") and self-feedback ("I yawned when he yawned").

And now assume something a bit more speculative is supported: that yawning in humans (along with a number of other internal state carrier signals) still carries some of the "chimp connotations" that affirm in-group status of others with whom we share contagious yawns. That is, when we get the self-feedback from having yawned in response to another person's yawn, there is a kind of cognitive fork that occurs: one response being "this person is part of my in-group," and another simultaneous response being a "checksum function" that replies to the "sense of in-group" with a "yes/no" reply.

For example you are in some social milieu (such as alone at a pub, waiting for a friend to arrive shortly) wherein you encounter people who may or may not be or become friendly. Someone sitting nearby yawns and you catch the contagious yawn and do so yourself. Now two things occur simultaneously in your brain as a result of the self-feedback from the yawn: one, the "sense of reassurance that the stranger is part of the larger in-group of community-at-large," and two, "checksum function, consisting of a concordant or discordant emotion" such as "you don't know him, don't assume he's friendly," or "he seems like a nice guy, it's OK."

Next we come to the issue of bigotry aside from racism and sexism:

Some forms of bigotry depend on observables: skin color, gender characteristics, age, etc. Some do not: religious bigotry, xenophobia (nationalistic bigotry), homophobia. You have no real way of knowing if the guy sitting next to you is, for example, a gay Jewish Frenchman, until he does something observable such as mentioning his husband or his rabbi or speaking French.

A modest hypothesis:

Bigotry is strengthened or weakened when the checksum function of an emotional state carrier incorrectly confirms another person as part of one's in-group, against one's prior beliefs to the contrary.

For example the other guy at the pub yawns, you yawn, your "all humans are in-group" function says Yes, your "checksum function" says Yes. A little while later the guy's husband walks in wearing a yarmulke, gives him a kiss, and then they start speaking French.

At that point you feel as if you were "fooled" in some way you can't put your finger on, and you resent both of them for it even more than you might have resented them if there had not been a contagious yawn. Or, conversely, you don't feel quite as much animus as you might have expected: without being conscious of it, the shared yawn helped set the stage for reduced animus.

How to test this:

First start with the "yawn video" procedure using self-declared racists as subjects; and videos of people, where control 1 is same-race with no yawns, control 2 is same-race with yawns, test 1 is disliked race with no yawns, and test 2 is disliked-race. After the videos, have the subjects rate their like or dislike of the person in the video on a 1-5 scale with 1 = strong dislike, 3 = neutral, and 5 = strong like.

Predictions: 1) Racists yawn significantly less often when watching yawns by members of their disliked races, than when watching yawns by members of their same races. 2) Racists rate the disliked-race yawners as more-disliked than the disliked-race non-yawners.

Second, repeat the same protocol using videos of what appear to be same-group members, where the distinction between test 2 and control 2 is that in the test conditions, the video concludes with the depicted person engaging in revealing behavior. For example, control: guy gets phone call and says "I have to go, that's my boss," vs test, guy gets phone call and says "I have to go, that's my husband."

Predictions: No significant difference in yawning response between test 2 and control 2 groups. Significant difference of level of dislike for "revealed out-group yawners" compared to "revealed out-group non-yawners." In other words, when the subjects yawn along with persons they later discover are out-group, they end up feeling differently about them. Some subjects will have significantly less dislike for the out-group yawners than for the out-group non-yawners. Some subjects will have significantly more dislike for the out-group yawners than for the out-group non-yawners.

Next step: find a way to parse the variables that correlate with the "more dislike" and the "less dislike" outcomes from the above. As they say in medicine, therein resides the hope for a cure.

OK, feel free to tear the above to shreds if there are flaws in my reasoning.

I would be empathetic to the comment above but the [redacted] is too damn long.

I wonder if there is any data on the influence of culture on human contagious yawning. My wife is from Colombia, where yawning is viewed as an indicator of hunger rather than fatigue.

@6: The cross-cultural aspect is interesting, I hadn't heard that yawning could be an indicator of hunger. If the empathy link is correct, then yawning isn't always an indicator of fatigue either, though, so I'm not sure it negates the hypothesis. A quick perusal of Pubmed and Google Scholar doesn't really give me anything useful...so I'm not sure if anybody has really done much cross-cultural work on contagious yawning. I'll keep looking.

I want to note that the assumed lack of empathy in autism is a canard.

This article made me yawn. What does THAT say?

Maybe it was the picture. Doesn't look like anybody I know, though.

I kind of really love this article to the point where I'm debating if I should start a Primate News round-up just so I can throw this in there.

That said, I've also heard before in a few classes that yawning can also be used as an aggressive communication signal as it shows off teeth (re: open-mouth threats). Thoughts as to how this might play along with that, or if there might be even any sort of correlation at all?

In response to Emily Willingham or others doubting the autism-yawning relationship. Here is a full text link to an empirical study. http://rsbl.royalsocietypublishing.org/content/3/6/706.full

Thank you for the post Jason. I think that mirror neurons may underlie many forms of social mimicry, including contagious yawning. Previous research has shown that people are less likely to mimic others that they do no like or do not feel are similar. This occurs on an unconscious level, people are generally not aware of their mimicry. I would expect similar findings with contagious yawning.

@Andrew -- that paper only states that autistic people don't contagiously yawn as often.

It does not state that autistic people have less empathy.

It presupposes that empathy and contagious yawning are related.

Having had experience with autistic people, I think it's much more likely that austistic people FEEL empathy but do not RESPOND / broadcast empathy "efficiently". Their feelings also are often of a slightly different "color" than a neurotypical's.

Granted, I think all of us posting on science boards are a little higher on the autistic spectrum to begin with:
http://www.wired.com/wired/archive/9.12/aqtest.html My score is 26 or 27. I dare Andrew to try it :)

I would hope that the researchers had a way of correcting for the possibility, but if they did then I missed it. Given the known "monkey see monkey do" mechanism and given the likelihood that such imitation might be more frequent with a "friend," were the reasearchers able to be certain they were seeing *REAL* yawns rather than just imitation ones? The one in the video looks like it happened WAYYY to quickly to be an actual yawn in response to another's yawn: yawns take a second or three to build up, but in the video it looked instantaneous.

- MJM

I had read somewhere that yawning in dogs is a sign of anxiety, not that the yawning itself says 'I'm anxious' but that the yawn is a request for reassurance from another dog (or human)that everything's okay, you can relax now. Communication between in group members is important: these are the animals that make up the immediate environment, whereas simple avoidance-aggression may suffice for contact with out groups.

Has anyone checked whether individuals relax after yawning?

Well, I gave it quick look and am not convinced:
From the paper: "...all subjects saw the ingroup videos before switching to the outgroup videos, as the outgroup exposure was a follow-up. "
Thus, mere order effects can explain these results: the chimps may have 1st yawned in response to yawns (many mechanisms could potentially result in this pattern) which happened to be familiar - then this response was over time somewhat diminished. Later (condition 2; outgroup videos) they watched LONGER at videos of outgroup chimps (a result also found in the paper and explainable by a number of things again) but by then the yawning response was already lower than at start. In other words, the REVERSE yawning pattern could have come about if only the authors had started with the unfamiliar chimp videos.
They need to do this tests before we will know what happened.

I think the mistake they made was using an iPod touch - these are so terminally passÃ©, any self respecting ape would yawn when handed one.

I just began yawning! I'm chimpathetic! Does that mean I'm not as high on the evolutionary tree as I once thought? :-(

I want to note that the assumed lack of empathy in autism is a canard.

Yeah, seriously. What I've found is that the brains of people on the spectrum work differently in a way that creates two-way problems in predicting mental states of others based on either reasoning from one's own mental and emotional experiences, in addition to a decreased sensitivity, in people on the spectrum, to external cues. For example, I am repeatedly assured that telling people over and over and over and over and over again that "I'm not saying your idea is BAD, it's just that..." is something that neurotypicals respond to positively, whereas I find it an annoying distraction when I'm on the receiving end even the first time, and it feels so patronizing that I would literally expect to be punched in the face if I did it to someone else - not to mention that feeling like I'm patronizing someone makes me intensely uncomfortable. Meanwhile, the average neurotypical's certainty that the average person with asperger's actually HAS a grossly inflated opinion of themselves and their own intelligence seems so durable as to almost fit the technical definition of "a delusion."

(If anything, I've found people on the spectrum are more empathetic - when the effects of their behavior on others are explained the average asperger's response, in particular, ranges from "but...that...that doesn't make any sense at all.. :(" to "oh...geez. I'm sorry. I didn't realize", whereas in explaining ASD symptoms to neurotypicals there's pretty much always an intense undercurrent of "well, why should *I* have to LEARN SOMETHING in order to get along with you; you're the one who's WEIRD" and "Gee, I wish *I* could make that kind of excuse and just get away with stuff!" is a pretty common reaction.)

Granted, I think all of us posting on science boards are a little higher on the autistic spectrum to begin with:

Quick Response To The GoDaddy Elephant Debacle

jgoldman — Sun, 03 Apr 2011 00:30:00 +0000

Quick Response To The GoDaddy Elephant Debacle

I was reading Christie's excellent post (and you should too) on GoDaddy CEO Bob Parsons' elephant killing incident (is it too early to be calling this #ElephantGate?)

Although I don't know quite enough about what is going on in Zimbabwe, I tend to err on the side of not intentionally killing elephants because - as I argued for the case of chimpanzees - they are very likely self-aware.

I wrote:

There is another important cognitive capacity that unites animals with high encephalization quotients (the ratio of brain to body size - I recommend going back to read my earlier post for the context of this argument): mirror self-recognition. Until relatively recently, it was thought to exist only in humans and great apes, though more recently, mirror self-recognition has been found in elephants, African grey parrots, dolphins, and (potentially) in Japanese macaques. Many believe that the mirror self-recognition test underlies a basic sense of self. Indeed, the great apes have shown varying levels of introspection, theory of mind, deception, and moral judgment - all abilities that require at least a rudimentary sense of self.

For me, the encephalization quotient gets the job done. While I approve of and encourage behavioral experiments with such species, I can't stand behind biomedical research on cetaceans, great apes, elephants, or any of the bird species whose cognitive capabilities mirror those of primates and cetaceans.

And if I wouldn't stand behind biomedical research on elephants, I don't see how I could stand behind killing them for food or (even worse) as a means of pest control.

If Bob Parsons had read my blog, he might have remembered that you can discourage elephants from raiding human villages and crops with only the use of a few cleverly placed audio speakers, playing the sound of angry bees. Exactly one year ago, I wrote:

Aside from the general importance of better understanding animal communication, as it can inform our understanding of human communication, this research has very practical implications as well. Elephants regularly raid the crops of humans; strategically placed beehives (or even just speakers broadcasting bee sounds or bee rumbles), could minimize human-elephant conflict and potential elephant deaths.

Definitely a better solution to what is certainly a real problem.

So that's my thinking on this issue at the moment.

That said, Christie said one thing that struck a particular nerve with me. She wrote:

I eat meat. I like meat. But there is a big difference between eating domesticated cattle or chickens, raised specifically for the purpose of food and (at least in theory) killed in the most humane way possible, and shooting an intelligent wild animal.

Regular readers of this blog know that I love my meat as well (who remembers the #BaconBlogWars of 2011?). But I am far from convinced that intelligence is the metric to be used to determine which animals are acceptable to eat. Nor am I convinced that domestication is a fair metric either. Part of what I do on this here blog is write about the cognitive abilities of the animals that we don't usually consider when we think about cognition and intelligence. I did this on Thanksgiving, for example, when I wrote about the social cognitive abilities of domesticated turkeys.

I wrote:

...while carving up your golden-brown turkey, take a moment to appreciate the complex social-cognitive abilities of these delicious birds. Domestic turkeys do more than just pair well with mashed potatoes and cranberry sauce: they can distinguish group members from strangers. And that's nothing to gobble at: human infants can't reliably distinguish among unfamiliar human faces until 19 weeks of age!

What it comes down to, for me, is this: I don't have any answers. But I do know that understanding the human relationship with non-human animals is extremely nuanced and very complicated.

So, by all means, continue eating your hamburgers, your turkey thighs, your bacon, your bacon-wrapped steaks, your bacon-wrapped hot-dogs, your bacon narwhals, and whatever else you might already enjoy. Just don't think that the cognitive abilities of those critters are so different from those of critters you wouldn't dream of eating. Their cognitive abilities aren't even so different from our own human cognition. Where they do differ, they more likely differ in degree rather than in kind.

Feel free to comment with your (respectful) thoughts, below.

Image source

jgoldman Sat, 04/02/2011 - 20:30

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Great, thoughtful post, man. Your blog has really been ratcheting up the quality level since your launch, and you are certainly keeping me thinking with your informed postings.

Hip hip hooray!

TTFN
Darin

And if I wouldn't stand behind biomedical research on elephants, I don't see how I could stand behind killing them for food or (even worse) as a means of pest control.

I would argue that there is a big difference between biomedical research and killing for food. Biomedical research on animals involves the animal having some sort of procedure (whether it is oral gavage right through to some form of surgery) and it is then monitored for a period of time, perhaps undergoes tests etc., - for a certain period of its life it is subject to stress caused by us. Hunting a wild animal and killing it for food generally exposes the animal to stress caused by us for a much shorter period. So long as the manner of death is quick and humane I would argue that killing for food is much more 'animal friendly' than biomedical research so you can be against biomedical research on these animals without being against killing them for food (or pest control for that matter).

For me, I think the biggest argument against killing these animals is the distress it causes to those animals left behind.

But as you said, it is a very nuanced area. I'm open to other points of view.

I agree that our relationship with animals is a complex and nuanced one.

But I think you are make a poor moral argument here.

Specifically, I fail to see how is that on one hand you claim to have "no answers", but on the other you encourage others to continue eating animal meat so long as they acknowledge our cognitive differences are only a matter of degree.

@Dario (#3): My intention in saying that was simply to make clear that I'm not making any sort of prescription or recommendations - more a series of observations. Or, at least, I didn't intend to provide an explicit moral code or judgment.

I do think that many people - in general - live in a state of relative ignorance about the varied levels of cognition and consciousness in the animals we eat. I think if you're going to eat something, you ought to have some awareness of what you're eating.

(Certainly this entire argument is only tangential to the elephant killing, as there are other known methods of keeping elephants away from human settlements... its just something I have been noticing, lately in terms of peoples' relationships with the food they eat)

the Godaddy CEO is jumping through hoops to justify his "hunt". If he really wanted to feed people he could just buy them cows. Or shoot a cow. If he wanted to rid the population of pests he could have shot some rats. Having said that, it makes perfect sense after the fact to eat the elephant.

@Jason

I agree given what is publicly known about the case that there was no good justification under the circumstances for killing this animal.

I was trying to ask how you, personally, can decide to eat meat of animals that you believe have the same cognitive abilities to that of great apes or humans (all differences supposedly being a matter of degree and not kind).

Elephants are definitely one of the most intelligent and aware species on Earth. Along with ellies, I would include in the top tier: chimps, bonobos, gorillas, dolphins (including orcas), some of the large whales, corvids (crows, ravens, and jays), and some parrots. Norway rats are also extremely intelligent and highly social animals that have been shown to engage in reciprocal altruism independent of kin selection; unfortunately they are treated as unfeeling products by most humans.

Bob Parson's name deserves to be dragged through the mud. Only someone lacking in empathy could kill an elephant.

When I heard about this event i was floored! How could anyone harm an elephant, well any animal for that matter. The reasons why he did it are not valid what so ever and I canelled my account with GodDaddy. I found an amazing promotion from Hostpapa (http://www.hostpapa.com/hostpapa-puts-its-support-behind-saving-the-ele…. They will donate $5 to Save the Elephants!
I used the coupon code âelephantâ and got 3 months free hosting.

I took my business else where.

Digitizing Jane Goodall's Legacy at Duke

jgoldman — Mon, 28 Mar 2011 12:05:00 +0000

Digitizing Jane Goodall's Legacy at Duke

A new piece by me today at the Scientific American Guest Blog, on some exciting news from the Jane Goodall Institute and Duke University:

Fifty years ago, in the summer of 1960 - the same year that a US satellite snapped the first photo of the Earth from space, the same year that the CERN particle accelerator became operational, the same year that the Beatles got their name - a 26-year-old Jane Goodall got on a plane in London and went for the first time to Gombe Stream Game Reserve, in Tanzania. She carried with her only a notebook and some old binoculars. Almost every day since the day Goodall arrived there in July 1960, somebody has been watching the chimpanzees (Pan troglodytes) of what is now called Gombe National Park, carefully recording their every movement...

...Duke University announced today that for the first time, fifty years of observational data from Gombe will be housed in the same location, in digitized format, so that additional researchers will be able to utilize it. Dr. Anne Pusey, chair of Evolutionary Anthropology at Duke, will run the project, which will be known as the Jane Goodall Institute Research Center at Duke.

Go check it out!

Goodall, J., & Pintea, L. (2010). Securing a future for chimpanzees Nature, 466 (7303), 180-181 DOI: 10.1038/466180a

Goodall J (1964). Tool-using and aimed throwing in a community of free-living chimpanzees. Nature, 201, 1264-6 PMID: 14151401

Pusey AE, Pintea L, Wilson ML, Kamenya S, & Goodall J (2007). The contribution of long-term research at Gombe National Park to chimpanzee conservation. Conservation Biology: The Journal of the Society for Conservation Biology, 21 (3), 623-34 PMID: 17531041

jgoldman Mon, 03/28/2011 - 08:05

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Defending Your Territory: Is Peeing on the Wall Just for the Dogs?

jgoldman — Mon, 07 Mar 2011 09:00:00 +0000

Defending Your Territory: Is Peeing on the Wall Just for the Dogs?

Welcome to Territoriality Week! Every day this week, I'll have a post about some aspect of animal or human territoriality. How do animals mark and control their territories? What determines the size or shape of an animal's territory? What can an animal's territory tell us about neuroanatomy? Today, I begin by asking two questions: first, what is the functional purpose of establishing territories? Second, to what extent can we apply findings from research on animal territorial behavior to understanding human territorial behavior?

It seems that everyone becomes an amateur animal behaviorist while walking their dogs. They notice that their dogs tend to pee on - well - just about everything, and infer that Fido is marking his territory. That most people are familiar with at least the basic principles of animal territoriality would suggest that the study of animal territoriality is fairly well established. Indeed, behavioral biologists and ethologists have been interested in animal territoriality since at least the 1920s. The main purpose of animal territoriality, it would appear, is excluding others from certain geographical areas through the use of auditory, visual or olfactory signals or by the threat of aggression. While there are certainly variations, territoriality seems to exist throughout the vertebrate phylum. While many of the early studies of territoriality focused on birds, later researchers investigated territorial behaviors in fish, rodents, reptiles, ungulates (hoofed animals, like cows), and primates. Territories may be held by individuals, by pairs, or by groups. They may be defended against anyone, against only members of the same species, or against only members of the same sex.

Why would territoriality be so widespread in the animal kingdom (at least among vertebrates)?

Dozens of reasons have been offered, including increasing security and defense, reducing the spread of disease, reinforcing dominance structures, and even localizing waste disposal. But an English zoologist named Vero Copner Wynne-Edwards suggested that territoriality operates in order to control population size. Julian Edney, a psychologist from Arizona State University, described Wynne-Edwards's hypothesis in this way:

[T]erritoriality is a link between social behavior (competition and dominance) and population control in many animals. Communities regulate their own numbers by the use of "conventionalized" competition, usually among males, for territory and the accompanying rights to food and (sometimes) mates. The winners are dominant animals and acquire social status, but since they are a fraction of the population, only a few community members get access to space, scarce resources, and females, thus limiting the size of the next generation. The next generation is also guaranteed food, because winners of territory spread themselves thinly over the terrain. Thus the habitat's food sources are not exploited beyond regenerative capacity, and a reasonable supply is ensured for the future.

In other words, the size of the population, and therefore the availability of resources for individuals within the population, is controlled by virtue of the fact that territory winners are generally the only lucky individuals who get to breed and pass their genes on to subsequent generations. Edney notes that Wynne-Edwards's theory is particularly attractive because, at least on some level, it applies to humans as well. It isn't much of a stretch to note that there is an observable relationship between territory ownership and social status, or between territory size and social status, in humans. For example, for much of modern history, one had to be a land-owner (not to mention white and male) in order to participate in government or even to vote. The corner office is so highly prized in business buildings partly because it is bigger than other offices.

It should come as no surprise to the frequent reader of this blog that I would argue that since humans are just another species from among many, a theory regarding animal behavior more likely than not ought to apply to human behavior as well.

Clearly, this territory reflects social status.

I find Edney's description of the origins of human territorial behavior quite interesting, especially considering the historical context in which he was writing. While he seems content to use animal behavior as an analogy for human behavior, Edney is quick to note that territorial behavior in humans, while similar in appearance to animal territoriality, may have different origins. He objects to the practice by which some other researchers would "beastopomorphize" humans. He writes,

...it does not follow from the gross similarities between the territorial behavior of some animals and man that the underlying mechanisms are the same in both, nor that they are genetic. To assume so, incidentally, has an interesting political consequence: It relieves man of the moral responsibility for his territorially aggressive acts and invites the rationalization of human territorial warfare as simple fulfillment of man's genetic predispositions.

He offers the following as evidence that human territoriality is different from animal territoriality, and in particular, is not derived from biology:

(a) Human use of space is very variable and not like the stereotypic spatial expressions of animals. This suggests a learned, rather than a genetic, basis.
(b) The association between territory and aggression, treated as fundamental by [some researchers], is not clear-cut in humans.
(c) Territories serve primarily "biological" needs for animals (shelter, food sources), whereas humans use them also for secondary purposes (e.g., recreation).
(d) Animals usually use only one territory and for continuous periods of time. Humans may maintain several territories (home, office, mountain cabin) in different locations.
(e) Humans also "time share" temporary territories (e.g., tables at a restaurant), whereas this is rare among animals.
(f) Total invasion of one group's territory by another is rare among nonhuman animals but occurs in human warfare.
(g) By virtue of their weapons, humans are the only organisms that can engage in territorial warfare without trespassing.
(h) Humans are also the only territorial organisms that routinely entertain conspecifics on home ground without antagonism (as in visiting).

Have the distinctions between humans and animals that Edney laid out (above) in 1974 held up in the face of empirical research? Do you think that human territoriality is qualitatively distinct from animal territoriality, or only quantitatively so? Do you think that human territoriality is purely the result of learning, experience, and/or culture? Or is human territorial behavior built upon evolutionarily ancient mechanisms, subsequently modified or shaped by culture?

Please jump in with your thoughts in the comments! Subsequent posts this week will address some of these, and other, questions about territorial behavior in humans and non-human animals.

Edney, J. (1974). Human territoriality. Psychological Bulletin, 81 (12), 959-975 DOI: 10.1037/h0037444

Dog statue image via Flickr/THEfunkyman. Whitehall Estate image via Flickr/Steven_M61.

jgoldman Mon, 03/07/2011 - 04:00

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So, what does it mean that the men working on our office building have taken to using the ladies room and leaving urine on the toilet with the seat up, despite the presences of perfectly adequate mens rooms at no further distance. Are they marking our territory as theirs or trying send a sexually aggressive message?

Here's one from the rural outreaches of N. Carolina. The coyotes have started leaving scat in my dog's territory and visa versa.
I want to keep my dog. I don't want to kill coyotes. What to do???

Tracy, I think they just like the smell of your poo.

I think a phenomenon that is so universal, as is human territorial behavior, must have some biological basis. Probably the tendency to group identification, which seems to be natural in humans, accounts for this universal occurrence of territoriality. It can be noted that one example of human territory sharing is in the case of the Australian Aboriginal people. Even though they had quite well defined lands, they could share their territory with other tribes, who's lands had been affected by drought. Human territoriality may be natural to some degree but it is also clearly culturally quite variable.

http://www.ktla.com/news/landing/ktla-cal-state-northridge-professor-pe…

Territory marking also serves to identify members of a pack, and there-by identify intruders as well. Dogs in a given area form distributed packs based upon barking behaviors, as well as familiar scat.
Years ago one of my dogs led me to understand the barking chaos that accompanied every intruder (mailmen, UPS trucks, etc)...and why dogs continued to bark when the intruder was clearly no longer an immediate threat.
The code turned out to be beautifully simple: barking intensity/frequency defines both the location of the intruder and a safety zone for those unable to defend themselves...with continuous updates till the intruder has left pack territory. The value of pack behavior that warns intruders of a defending army, and provides safety information is immeasurable.

For cats, the chin-rubbing scent marking is a way of knowing where they've been. Each time I've moved with cats, I've scratched under their chins then methodically marked tracks for them - out the window, down the banister, down the stairs, and out along the edges of the yard in sheltered paths -- before letting them out the first time.

It's quite clear they're following those tracks, sniffing and renewing them. Once they venture away from the lines I marked I can see a much more tentative progress, more looking around and up -- and when they get startled they run until they cross one of those lines then turn and follow it back to safety.

The same scent marking works for new scratching posts

I can also see the neighbor cats that come to the same space from elsewhere notice the scent marks too.

Result, on a sunny day, a 'clowder of cats' -- sometimes half a dozen or more scattered around the sunny warm yard, each carefully far enough from the others that they can all relax for a while.

It sounds pretty far fetched to me that human territoriality would have absolutely no biological basis. Since humans are socials creatures, wouldn't it be best to compare territoriality on the group level rather than the individual level? Or perhaps group territoriality has a larger biological basis than individual territoriality does. Also, some non-human animal territories temporarily dissolve under high resource availability, so maybe the issue would be best investigated related to some limited resource.

e) Timeshare. The various pods of Orca will time share a single unique pebble scratching beach on the East side of Vancouver Island. They are polite to awaiting pods, and appear to share gratefully what looks like a pleasurable activity.

@Tracey: Not sure what to tell you, though I'm not sure science can help you in this case :-)

@Richard: Fantastic. I was trying to think of an example of this sort of "timeshare" behavior in the animal kingdom, but couldn't come up with anything. Do you know if this behavior has been described in a journal article?

A discussÃ£o de territÃ³rio e seus correlatos tem evoluido nos Ãºltimos anos nas ciencias humanas, sobretudo na Geografia. Acredito que a teoria utilizada estÃ¡ equivocada, porque na atualidade se discute territÃ³rio nas multiplas dimensÃµes, ou seja, polÃtica, economica, cultural e natural.

Cats often have timesharing of territory:
http://www.cat-health-detective.com/catbehavior.html

Men smoke cigars to mark territory. That's why it often seems presumptuous or pretentious when a younger man smokes a cigar; it's as if he hasn't earned the status to warrant marking territory.

That's how I think of cigar smokers.

a) Marriage customs and standards of handsomeness vary wildly but that doesn't mean that sex and mating aren't human instincts. Cats' use of territory is variable, too.

b) Visceral reactions, from "get off my lawn" fury and No Hunting to love of the ancestral farm to whatever drives amti-immigrant discrimination, suggest that there are very basic feelings involved.

c) Did someone fail to notice the invasion of North America by Europeans 500 - 100 years ago? Territories (hunting grounds, farm lands, fishing or timber rights, access to drinking water) are extremely important to survival. You just don't notice because you're in a dominant society and a prosperous time. Indian wars were fought over hunting rights. Non-agressive people, like the Inuit, were pushed to the least hospitable land.

d) animals that use different places, like hippos with their daytime river and nighttime pasture, may well defend more than one territory. So will baboons and other monkey with fruiting trees.

e. Cats time-share their territories, especially urban cats with high population densities; Scientific American had an article about it, years ago. As for time-sharing at restaurants--have you ever watched birds at a birdfeeder? They take turns, flight after flight, until an Important Personage like a jay comes along--then they get out of the way.

f. Jane Goodall observed chimps in genocidal territorial warfare when they wiped out a group that had split away from the main troop.

g. Monkeys throw sticks and possibly stones, They also howl or yell to establish territory by show of strength. A lot of animals make territorial displays at their borders and may not trespass but simply "negotiate" moving the border by making their opponent back up.

h. Cats also tolerate others in their territory if food supplies are good. another flexible behavior; just look at the colonies of feral cats that someone feeds. Anecdotally, some cats visit particular other cats and so have friends. I owned a cat that would bring home hungry young cats and would encourage them to eat from its outdoor bowl with little prrpy noises. Wolves have been described visiting relatives in neighboring territories.

Does anybody know of any single cell organisms that exhibit territoriality?

So could this explain at least in part why some woman tend to get involved with aggressive men, time after time. Despite the fact it leads to abusive, controlling and generally unsatisfying relationships. I realize self esteem, self efficacy and family background play a role as well. I have always been a predominately non-aggressive male, especially as former Marines go. I have done a great deal of self study in psychology, philosophy and the sciences in general. I often find myself in the role of sympathetic ear to female friends over the years. They go on and on about the mental and or physical abuse and infidelity. I proposed my own theory that possibly when distracted and caught up in the selection process at the local bar they were driven subconsciously by an ancient instinct. Possibly they were feeling drawn to aggressive men because 10,000 years ago that kept you and you children safe. Which came first, the abusive male or the woman that rewarded him for it?

Except for the example of orcas mentioned above, it would seem only land animals can mark territory, since it would be pretty difficult to establish turf in water. Thoughts?

Do you think the level of testosterone is related to one's desire to own a big and spacious house? Since testosterone is related with dominance and power.