Ever since Darwin’s On the Origin of Species, the boundary between humans and animals has become increasingly blurred. One by one, our claims to some inherent superiority over the beasts have been undermined by scientific research: it’s not just humans, it turns out, who use tools, have language, even develop cultures. For three decades, Michael Tomasello, co-director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, has worked to pin down exactly what it is that marks out mankind from its closest relatives. In a series of books – including The Cultural Origins of Human Cognition (1999), Why We Cooperate (2009) and now A Natural History of Human Thinking (out in February) – he’s argued that the answer lies in some unique features of the way our minds work. He talks to Tony Wood about individualistic apes and the evolutionary advantages of being sociable.
TONY WOOD A lot of your work has involved looking closely at chimpanzees and human infants, and at differences in their cognitive abilities. When were you first drawn to making comparisons between humans and other primates, and why?
MICHAEL TOMASELLO I’ve always been interested in the evolution of human cognition, but my first studies were on cognitive development in human children. By chance, my first job was at Emory University, home of the Yerkes Primate Center. The first time I went to observe the chimpanzees, they did many things similar to those I was observing in young children, but other things that were very different. It’s the combination of similarities and differences that I think makes non-human primates, and great apes in particular, inherently interesting to almost everyone.
TW You’ve been able to pin down some crucial divergences between humans and great apes in terms of how they act and think. How would you sum up the fundamental differences, the things that make us distinctively human?
MT We humans have the illusion that we’re independent thinkers. But we use a language to think and that was given to us by our forebears. And we follow norms of reasoning, and those norms come basically from our culture. When we reason, we think about how other people might comprehend and/or challenge us, and so we build into our thinking inferences that anticipate the reactions of others. All of this is to say that the main difference between human thinking and great ape thinking is that great apes aim to solve their own individual problems with their own individual wits. Humans do that, too, but they’re doing it with cognitive representations and modes of inference crafted for communication with others in their social group. Great apes have individual intentionality, but humans have shared intentionality.
TW You’ve written very persuasively about how humans are uniquely cooperative (at least compared to chimps). How does human collaboration differ from the kinds of seemingly common efforts made by other species – certain kinds of swarming bacteria, for example, or bees, ants, termites, etc?
MT Ants, bees and other eusocial insects are cooperating with kin. The mechanisms they use to cooperate are hardwired. Human beings are using their flexible intellectual skills to find creative ways to cooperate with others. And much of human cooperation is governed by moral considerations, which make us feel not just that we would like to do something, but that we ought to do something. Cooperation by itself does not have to be psychologically complex, but the human version is.
TW In your latest book you describe a two-stage process through which patterns of reasoning developed that are very specific to humans. You mention the emergence, first, of what you’ve called “joint intentionality”, and then of “collective intentionality”. What’s the basic difference between the two, and what new capacities were gained in the shift from one to the other?
MT Joint intentionality is about two individuals interacting with one another dyadically, whereas collective intentionality is about group dynamics and the individual’s relation to those. Much research suggests that dyadic relationships are different from groups; in particular, if I opt out of the dyad there is no social anything left, whereas that is not true if I drop out of a group which goes on without me. In any case, joint intentionality is about me putting my head together with one other person to pursue a joint goal, or to attend to something together. Collective intentionality is about me tuning into the conventions, norms and institutions that constitute my cultural group. They are collective entities that existed before I came into the world, and that have an objectivity all their own.
TW What do you think caused these cognitive leaps? And where does language fit into the story?
MT Humans were forced by changing ecological conditions into a more cooperative way of making a living. For example, it may have been that the expansion of terrestrial monkeys – baboons, say – during early human evolution deprived individuals of the opportunity of going for the fruits they could normally acquire on their own. They had to go for some new things, and one ecological niche that was open – or at least, not occupied by other primates, only by social carnivores like lions and hyenas – was pursuing resources they could only obtain collaboratively. Later, as human groups began competing with one another, distinct cultures began to develop. Language evolved as modern humans conventionalised early humans’ primitive forms of communication – mainly pointing and pantomiming.
TW The collective seems to be a central factor here – spurring the emergence of collaborative behaviours and rewarding them, in a kind of positive feedback loop. Yet you also imply at one stage that this doesn’t necessarily apply to the last 10,000 years, once agricultural surpluses, stratified societies, political authorities, etc, emerge. How does this change in the kinds of collectivities humans inhabit – from small kin groups to large abstractions like nations – affect our basic willingness to cooperate? Is it still the advantage it originally was?
MT Humans are mainly adapted for collaborating in small groups, and also in larger groups if they are organised culturally, and thus internally homogeneous. The problem comes with the origin of agriculture, when human groups start to become extremely complex, with many different kinds of people from many different cultural and ethnic groups in them. This makes cooperation much more difficult in many ways. Whether we can scale up our skills and propensities to the contemporary situation is still to be seen.
TW Your work is very persuasive about the interaction of biological and cultural factors – processes of “co-evolution”. In some ways, though, you’re pushing against a very deterministic tide in contemporary culture, where evolutionary adaptations from the Pleistocene are crassly hauled in to explain everything – sexual behaviour, why men buy expensive watches, and so on. How do you account for this trend, apart from a preference for simplistic explanations?
MT No, that’s pretty much it: a preference for simplistic explanations.
TW What have been the big changes in evolutionary anthropology in the last decade or so, and where would you say it’s headed?
MT Certainly one of the major trends has been the recognition of how unusual humans are, among primates, in their tendencies towards cooperative living. Explaining human ultra-cooperation in evolutionary terms is no easy task, and that’s at least one of the major directions that will shape evolutionary anthropology in the 21st century. Another, of course, is our increasing understanding of the particular trajectory of human evolution in light of the startling new discoveries that arrive almost monthly in evolutionary genetics.
TW In Why We Cooperate, you touched on the classic debates about human nature, coming down on the side of Rousseau rather than Hobbes. (Chimpanzees, meanwhile, come out as Machiavellian.) There are obvious political valences to a lot of your arguments; is that something you welcome, or indeed actively seek?
MT Science puts tools and materials on the shelf for people to use. How people use them in their individual decision-making, or how politicians might use them for shaping public policy, is not in our hands –
though of course we can voice our opinions like anyone else. I myself am simply committed to making sure that the information that is out there for people to use is as accurate as possible. §