That's the question Herrmann et al. are trying to answer in this study published in September 2007: Humans Have Evolved Specialized Skills of Social Cognition: The Cultural Intelligence Hypothesis.

The researchers were interested in the question of whether differences between human and ape cognition are qualitative or quantitative. They contrast these two hypotheses regarding intelligence:

One hypothesis is the general intelligence hypothesis. Larger brains enable humans to perform all kinds of cognitive operations more efficiently than other species: greater memory, faster learning, faster perceptual processing, more
robust inferences, longer-range planning, and so on.

...

In the case of humans, one reasonable hypothesis involves extending the primate social intelligence hypothesis to reflect the fact that humans are not just social but "ultra-social". That is, whereas primates in general have
evolved sophisticated social-cognitive skills for competing and cooperating with conspecifics, humans have also evolved skills that enable them to actually create different cultural groups, each operating with a distinctive set of artifacts, symbols, and social practices and institutions.
To function effectively in the cultural world into which they are born, human children simply must learn to use these artifacts and tools and to participate in these practices, which require some special social-cognitive skills of social learning, communication, and "theory of mind".

They call this latter hypothesis the cultural intelligence hypothesis.

They say that each hypothesis makes specific predictions. The cultural intelligence hypothesis predicts that at some point in their development, human children should diverge from apes with respect to certain types of cognition, specifically those dealing with social aspects such as social learning, communication, and theory of mind (figuring out what others are thinking). The general intelligence hypothesis should predict uniform difference between humans and apes, that the lines should overlap until humans outstrip other apes, and that there shouldn't be large differences between types of cognitive tasks.

To test this, they came up with the Primate Cognition Test Battery (PCTB), a series of tests divided into two broad categories:

Physical cognitive tasks: Testing cognitive abilities related to space, quantity, and causality. Specifically related to interactions with inanimate objects.

Social cognitive tasks: Testing cognitive abilities related to social learning, communication, and theory of mind. Specifically related to interactions with other agents.

They tested three species: 105 humans around 2.5 years old, 106 chimpanzees from 3 to 21 years old, and 32 orangutans from 3 to 10 years of age. Keep in mind that apes mature much more quickly than humans.

They administered the test battery to all subjects and here's what they found:



Toddlers and chimps performed the same on physical cognition tasks, and both performed better than orangutans. However, at social cognition tasks toddlers outperformed both chimps and orangutans, who did as well as each other.

These results seem to nicely confirm the authors' hypothesis, that humans diverge from other apes with respect to sets of skills dealing specifically with interaction with others.

But wait a minute...all the experiments were administered by humans. Wouldn't it make sense that in tasks specifically related to interacting with others, that subjects would respond better to members of their own species?

Here are a couple of videos from the supporting material that comes along with the paper. They show clips from experiments with a toddler and then a chimpanzee on the first social cognition task, learning how to access a desired item from an object after observing how to access it by a person:





A couple of things you might notice right off the bat...The experimenter is speaking to the child in the first clip (this was done in Germany, by the way). The second clip, which is poorer quality, doesn't even have sound. Are we expected to believe that interaction with a member of the same species, who can use language to direct and encourage the child, isn't going to affect the subject's ability to learn the task?

That's what the authors would have us believe. From the discussion:

It is certainly an issue that the test battery was both constructed and administered by humans. But in previous studies with these same tasks from the social domain, there is no evidence that the use of human versus conspecific interactants had any significant effect on performance.

The studies they cite are referenced in the supporting material. So now I need to go look at those studies, but color me skeptical. Are we supposed to believe that for such tasks, a child would do as well with a chimp or orangutan teacher? Or that language use makes no difference in performance?

I have no idea why they didn't control for language use. It would have been trivial for experimenters to not speak when administering tasks to the children, and the experimental situations would have been much more analogous. My guess is that the children would have performed much worse in a non-linguistic environment, but that actual experiment would need to be done.

So back to the original question: Are humans "socially smarter" than other apes? I'd be inclined to think so, but the way this study was carried out, I wouldn't use it to support that position.

Anybody else have any thoughts on this?

Herrmann, E., Call, J., Hernandez-Lloreda, M.V., Hare, B., Tomasello, M. (2007). Humans Have Evolved Specialized Skills of Social Cognition: The Cultural Intelligence Hypothesis. Science, 317(5843), 1360-1366. DOI: 10.1126/science.1146282