What Makes Us Human?
One of the most enduring pursuits in cognitive science is identifying the factors that separate us from lower animals — and while it might at first seem like a trivial matter (“well, we’re just a lot smarter!”), it is actually very difficult to scientifically quantify those factors.
In my last post, I discussed some recent advances in the understanding of rat cognition — it turns out that their brains are much more advanced than we first thought. And there have been a lot of recent advances in the understanding of ape cognition; they perceive space, quantities, categories, causality, and intention in ways that are more complex than we previously realized. So if we are so much more similar than we thought, what separates us?
At a keynote speech at the British Psychological Society’s CogDev 2013 conference, the researcher Michael Tomasello outlined his belief that the answer, or at least a significant portion of it, can be found in our ability to collaborate. In experiments with apes and human children, experimenters have seen some very interesting differences that point to underlying differences in how we work together to achieve goals.
Apes, including chimpanzees and bonobos, collaborate to achieve goals (usually the acquisition of food). Children do the same. However, they do so in different ways — for example, children take turns in a collaborative context, while apes do not. Children prefer to forage collaboratively, while apes prefer to go it alone when they can. Kids understand their collaborator’s role, and can play that role quickly and without much difficulty. Apes have to re-learn the new role as if they had never even seen it. The list goes on.
Of course, these differences could be ascribed to a number of things, but Tomasello believes that humans have evolved specifically to engage in “joint intention,” which is something that apes do not have. Infants will point to an object just so that an adult will look at it and create shared attention; they will also show an object to an adult without making any requests to play with it — they just want to share attention. This is called the informative motive, and it seems to only be present in humans.
These collaborative actions “create shared intentionality infrastructure for cooperative communication,” and Tomasello believes that the cognitive adaptations that have arisen to allow this joint intentionality are behind uniquely human processes like cognition, communication, culture, and morality.
So where did these cognitive adaptations come from? One theory is that they arose when competition for food increased, possibly from some great apes moving from the trees to the ground; humans responded by developing these collaborative abilities so that they could hunt larger game and continue to prosper.
No matter what brought about these adaptations, it is clear that there are some significant differences between humans and great apes when it comes to cognition, and Tomasello makes a very compelling case that these differences are motivated by differences in collaborative ability. As he has been a very prolific and influential researcher over the past several decades, I have no doubt that we will be hearing more about this from Tomasello in the near future.
Also, Tomasello has a new book coming out soon — A Natural History of Human Thinking. I think it is going to be a good one, so grab a copy of it next February when it comes out.