Computational approaches to cognition: the origins of social and causal reasoning in children and primates

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Imagine watching as a fellow traveler approaches a ticket machine, rubs a pound coin carefully on the machine's side, and then inserts it into a slot before retrieving a ticket. When it's your turn, what do you do? Inserting a coin seems important, but perhaps you would rub it first too - after all, that guy must have had a reason to do so. From an early age, children are quick to copy another's action, and from very little feedback they can screen off unnecessary actions and focus on what works. But in a context like this they usually copy all the actions in a sequence, even those that seem unlikely to matter. Chimpanzees don't do this: if they can see that an action is pointless, they don't copy it. Of course, both species are intensely social beings, and their causal learning takes place in a rich social context. A natural question is therefore how social interaction informs and influences learning. But surprisingly, we know very little about how an actor's intentions and the observer's prior physical knowledge feed into children's causal judgments, and still less about how, if at all, our primate relatives take advantage of either source of information. We propose to try and disentangle how learners of different primate species, including our own, weigh these sources of information when they decide what to copy. We will first use a computational model that tries to predict how learners should learn from different kinds of evidence. We will then conduct a study examining what learners of different species actually do. In the study, some participants will see two purposeful actions precede an outcome (as in the man rubbing and then inserting the coin). Others will witness the same two actions, but the demonstrator will appear to produce the outcome accidentally (e.g. ignoring the ticket, and continuing to explore the environment). A third group will see a pedagogical demonstration (imagine the man catching your eye and pointing at the coin before rubbing it: would you be more likely to copy him?). Cutting across this comparison, we will vary mechanical plausibility. For half of the learners the first action will be particularly unlikely to have causal power (imagine the man rubbing one coin and then inserting a different one). We will measure the tendency of children, apes and monkeys to produce the two actions after the demonstrations. If they integrate some prior physical knowledge, they will be less likely to copy both actions if one is mechanically implausible. However, if they integrate social knowledge, they should be more likely to copy both actions if the actor did them on purpose, and this may lead them to override any previous bias. Follow up studies will look at related questions, such as how different primate species learn to cooperate and coordinate joint behaviors. (Think of helping someone move a heavy sofa. Both people not only have the shared overall goal of getting the sofa out, they have intermediate goals like avoiding bumping into the walls or getting stuck in doorways, and each person has a separate role in achieving those goals). The fact is that although all primate infants seem to learn from observation, something about human children is different, and allows them to acquire a working knowledge of the multitude of artifacts developed in their culture, from crayons to ipads, with breathtaking speed. Meanwhile other primates such as chimpanzees spend several years getting to grips with just a few skills, such as the use of a hammer stone to crack nuts, despite many hours of close observation. Understanding what differs may give us helpful insights into what sorts of things children are uniquely adapted to learn. The research will therefore provide important insights into how children learn from teachers, both formally in the classroom and informally in the world.