Friday, January 20, 2012

'Human beings are learning machines,' says philosopher

Innately curious <i>(Image: Misha Gravenor for </i>New Scientist<i>)</i> 
Innately curious (Image: Misha Gravenor for New Scientist)

Prevailing wisdom holds that we are born with an innate understanding of the world. Wrong, says philosopher Jesse Prinz, who tells Michael Bond why he thinks many of our "innate" abilities are actually a result of the culture we live in

In your new book you claim that culture rather than biology determines our lives. Hasn't science moved on from this "nature versus nurture" debate?
I'm not trying to deny the biological contribution to human nature or to overly dichotomise the nature/nurture distinction - everyone recognises that the truth is somewhere in the middle. The point is that in scientific writing on this topic, the nurture side has been inadequately expressed, especially in books directed towards a more general audience. They suggest a very inflexible view of human nature, that we are determined by our biology. From my perspective the most interesting thing about the human species is our plasticity, our flexibility.

One of the ideas you take issue with is that we are all born with innate knowledge about the world. Why do you reject that?
If you look at the dozens of journal articles published each month supporting the view that babies already know a lot about how the world is organised, they rarely show these capacities in the earliest days of life. They show them emerging at 3 months, 6 months or 12 months. When they test newborn infants, these capacities are often absent. This already suggests that learning might be taking place.

Can you give me an example of such learning?
If you look at the capacity to keep track of quantities, or understand causation, or the knowledge that one object won't pass through another object when they come into physical contact, all of these derive from things we can readily observe in our environment, things that are constantly available to our senses. Do we really need innateness to explain why we know at a young age that if you put your cup down on the table it won't pass through the table and hit the floor? Infants are in a very good position to discover basic physical facts about the world through their exploration of their environment.

What about the popular notion that boys and girls are born with predilections for certain kinds of toys or activities?
Many girls in our society gravitate towards wearing pink, for example, but to assume that's an argument for innateness is of course preposterous. It would be impossible to make a case for an innate pink preference among girls. With respect to toys, there is tremendous pressure to adopt the cultural norms we see all around us; it's impossible to avoid them. A young girl who is discouraged from playing with gender-specific toys is going to end up feeling isolated from their group. But these dispositions should never be taken as evidence for innateness.
For example, a study in 2002 tried to establish innate gender preferences by showing that female monkeys like to play with pans and dolls, whereas male monkeys like to play with trucks and balls. But in my view the study was flawed. Beyond the absurdity of saying that male monkeys innately like trucks, the authors actually found that they play with all toys more than the females, and they liked the pan as much as any stereotypically male toy.

So why are our dispositions so often taken as evidence of innateness?
It is striking in general that human beings mistake the cultural for the natural; you see it in many domains. Take moral values. We assume we have moral instincts: we just know that certain things are right and certain things are wrong. When we encounter people whose values differ from ours we think they must be corrupted or in some sense morally deformed. But this is clearly an instance where we mistake our deeply inculcated preferences for natural law.

At what point with morality does biology stop and culture begin?
One important innate contribution to morality is emotions. An aggressive response to an attack is not learned, it is biological. The question is how emotions that are designed to protect each of us as individuals get extended into generalised rules that spread within a group. One factor may be imitation. Human beings are great imitative learners. Rules that spread in a family can be calibrated across a whole village, leading to conformity in the group and a genuine system of morality.
Nativists will say that morality can emerge without instruction. But with innate domains, there isn't much need for instruction, whereas in the moral domain, instruction is extensive. Kids learn through incessant correction. Between the ages of 2 and 10, parents correct their children's behaviour every 8 minutes or so of waking life. In due course, our little monsters become little angels, more or less. This gives us reason to think morality is learned.

One of the strongest arguments for innateness comes from linguists such as Noam Chomsky, who argue that humans are born with the basic rules of grammar already in place. But you disagree with them?
Chomsky singularly deserves credit for giving rise to the new cognitive sciences of the mind. He was instrumental in helping us think about the mind as a kind of machine. He has made some very compelling arguments to explain why everybody with an intact brain speaks grammatically even though children are not explicitly taught the rules of grammar.
But over the past 10 years we have started to see powerful evidence that children might learn language statistically, by unconsciously tabulating patterns in the sentences they hear and using these to generalise to new cases. Children might learn language effortlessly not because they possess innate grammatical rules, but because statistical learning is something we all do incessantly and automatically. The brain is designed to pick up on patterns of all kinds.

How hard has it been to put this alternative view on the table, given how Chomskyan thought has dominated the debate in recent years?
Chomsky's views about language are so deeply ingrained among academics that those who take statistical learning seriously are subject to a kind of ridicule. There is very little tolerance for dissent. This has been somewhat limiting, but there is a new generation of linguists who are taking the alternative very seriously, and it will probably become a very dominant position in the next generation.

You describe yourself as an "unabashed empiricist" who favours nurture over nature. How did you come to this position, given that on many issues the evidence is still not definitive either way?
Actually I think the debate has been settled. You only have to stroll down the street to see that human beings are learning machines. Sure, for any given capacity the debate over biology versus culture will take time to resolve. But if you compare us with other species, our degree of variation is just so extraordinary and so obvious that we know prior to doing any science that human beings are special in this regard, and that a tremendous amount of what we do is as a result of learning. So empiricism should be the default position. The rest is just working out the details of how all this learning takes place.

What are the implications of an empirical understanding of human nature for the way we go about our lives. How should it affect the way we behave?
In general, we need to cultivate a respect for difference. We need to appreciate that people with different values to us are not simply evil or ignorant, and that just like us they are products of socialisation. This should lead to an increase in international understanding and respect. We also need to understand that group differences in performance are not necessarily biologically fixed. For example, when we see women performing less well than men in mathematics, we should not assume that this is because of a difference in biology.

How much has cognitive science contributed to our understanding of what it is to be human, traditionally a philosophical question?
Cognitive science is in the business of settling long-running philosophical debates on human nature, innate knowledge and other issues. The fact that these theories have been churning about for a couple of millennia without any consensus is evidence that philosophical methods are better at posing questions than answering them. Philosophy tells us what is possible, and science tells us what is true.
Cognitive science has transformed philosophy. At the beginning of the 20th century, philosophers changed their methodology quite dramatically by adopting logic. There has been an equally important revolution in 21st-century philosophy in that philosophers are turning to the empirical sciences and to some extent conducting experimental work themselves to settle old questions. As a philosopher, I hardly go a week without conducting an experiment.
My whole working day has changed because of the infusion of science.


Jesse Prinz is a distinguished professor of philosophy at the City University of New York, specialising in the philosophy of psychology. He is a pioneer in experimental philosophy, using findings from the cognitive sciences, anthropology and other fields to develop empiricist theories of how the mind works. He is the author of The Emotional Construction of Morals (Oxford University Press, 2007), Gut Reactions (OUP, 2004) and Furnishing the Mind (MIT Press, 2002). His latest book, Beyond Human Nature: How culture and experience make us who we are, is published by Allen Lane in the UK this month

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