In a series of studies, Michael Tomasello and colleagues at the Max Planck Institute for Evolutionary Biology have attempted to isolate what makes human cognition different from that of higher primates. Through a series of studies, they concluded that the key difference is what they call “shared intentionality,” the “we” factor. Humans have it from a very early age; primates do not.

Tomasello and Malinda Carpenter summarize their findings in a 2007 article in Developmental Science. They have found that chimps “follow the gaze of others to external locations, they check back with the other if they do not see anything interesting, they quit looking if they see nothing interesting repeatedly, they pursue contested food only if a dominant cannot see it, and they visually conceal their approach to contested food if there is a dominant competitor nearby.” Human infants and young children do this as well. But humans do more: “From before the first birthday, human infants do not just follow the gaze of others to external targets, and do not just want to know what the other sees, they also attempt to share attention with others. . . . Importantly, joint attention is not just two people experiencing the same thing at the same time, but rather it is two people experiencing the same thing at the same time and knowing together that they are doing this” (121).

The difference is evident in the differences between the response of chimps and human infants to the act of pointing: “suppose that an adult points to an opaque bucket for the infant. If he does this out of the blue, the infant cannot know whether he is pointing to direct her attention to the container’s color, its material, its contents, or any other of myriad possibilities. However, if they are playing a hiding–finding game together, and in this context the adult points to the bucket, the infant will very likely infer that he is pointing to inform her of the location of the hidden object. Fourteenmonth-old infants make just such an inference in this situation . . . , but chimpanzees and other apes do not. It is important to recall that apes are very good at following gaze direction in general (including that of humans), and so their struggles in this task do not emanate from an inability to follow the directionality of the pointing cue; rather, they do not seem to understand the meaning of this cue. Because they do not share with the human the joint attentional frame (common ground) of the hiding–finding game, they follow the point to the bucket and say, in effect, ‘A bucket. So what? Now where’s the food?’ They do not understand that the pointing is intended to be ‘relevant’ to the searching as a shared activity” (122).

Apes are individualists: “apes are mostly concerned with their own individual goals. They use or exploit others – by gathering information from them, manipulating them as social tools, coordinating actions with them for their own benefit – and often compete with them as well.” Humans are, as the philosophers have long known, social animals: “Human children often are concerned with sharing psychological states with others by providing them with helpful information, forming shared intentions and attention with them, and learning from demonstrations produced for their benefit” (124).

Here’s a neat beginning definition of human nature: We are the creature capable of saying “we.”

(Tomasello and Carpenter, “Shared Intentionality,” Developmental Science 10:1 [2007] 121-5. Thanks to Prof. John Jefferson Davis of Gordon-Conwell Seminary for the artcle.)