Maybe it's the scuffed cowboy boots. Or the shoulder-length curls. But Steven Pinker doesn't look the way you expect the director of the McDonnell-Pew Centre for Cognitive Neuroscience at the Massachusetts Institute of Technology in Cambridge, Massachusetts to look.
The diffident 43-year-old seems too young, too funny, too downright nice to have acquired that title. "If you sit here the sun won't be in your eyes," he says, positioning two chairs opposite each other yet close together in his MIT office. No desk in between, no power play. He ignores the messages on his computer screen and the continuous purring of his telephone. Before long he is telling one of his favourite jokes - the one about the similarity between a primitive sea creature that consumes its own brain and a tenured professor.
Steven Pinker doesn't look like a troublemaker either. But his latest book, How The Mind Works, has caused an academic firefight, with some of the heaviest attacks being launched from Harvard University, just a few streets away. "Inconsistent" and "opinionated" are some of the milder accusations from Harvard biologist Stephen Jay Gould and others, who are suspicious of what Gould has labelled "Darwinian Fundamentalism".
Pinker's book has not just earned him illustrious enemies. It has also turned its author into a celebrity scientist, the Carl Sagan of the human brain. Or, as Time magazine recently christened him, an Evolutionary Pop Star. If the brain is the next big thing in scientific publishing, then Pinker, with his accessible and exuberant writing style, is its ideal populariser.
"No other science writer makes me laugh so much," University of Oxford zoologist, Mark Ridley, wrote in his review of How The Mind Works. Ridley was referring to Pinker's playful use of jokes to illustrate his points - Mae West lines such as "Men like women with a past because they hope history will repeat itself", or one prostitute's observation that men " . . . are not paying you for the sex. They're paying you to go away afterwards."
The first minutes of a lengthy interview, however, reveal Steven Pinker to be far more than a poster boy for cognitive studies. He is, above all, a scientist and teacher who never allows his contagious excitement about the subject to unseat his precision. When asked to define the mind, he politely observes that "Scientists don't define things. My theory is that the mind is the information processing activity of the brain. The mind is what the brain does." And the brain, being an extraordinarily complex kind of computer, "computes what it does because it is the product of the evolutionary process. That's why our computations are about things like how objects fall or how to make people fall in love with us."
To understand why the brain thinks as it does, Pinker believes that you must first understand its structure. How The Mind Works examines computational models of the brain's mechanisms - its circuitry - and goes on to describe the evolution of our reasoning abilities, social and sexual behaviour and emotions. Much of this is straightforward science and Pinker stresses that "most of the things in the book, I didn't discover. I just report them."
If that was all there was to it, How The Mind Works would be just another textbook and Steven Pinker just another psychologist. His emphasis on evolution, however, and his theory that "the mind is a system of organs of computation designed by natural selection to solve the problems faced by our ancestors in their foraging way of life", guarantees controversy. He characterises much of the recent criticism as "some people getting things just plain wrong" and defends his position with a series of examples.
Take, for instance, the evolutionary development of the brain as a sophisticated lying machine. "The brain wasn't selected for its ability to register or represent the truth," Pinker explains. "Sometimes truth is handy: you want to know if it's a lion or a rabbit in front of you, for instance."
But selling oneself, attracting mates or allies, is another matter. "All Darwinian creatures are in competition," he says. "Other people will give some credence to how you present yourself and that gives an opening for you to represent yourself as a little more honest, more generous, more virile than you may be." The consequences are obvious and familiar. "Given that people have a tendency to lie about themselves, that puts corresponding pressure on the audience to be lie detectors. The logical conclusion is that you should believe your own lies."
Critics of such evolutionary psychology often accuse its adherents of reversing Charles Darwin's formula that "the present is the key to the past," but Steven Pinker deflects that criticism. "The present may be the key to the past in terms of what we know," he ventures, "but the past may be the key to the present in a causal sense."
For 99 per cent of our evolutionary past we were hunter-gatherers and that, Pinker argues, must be the starting point for decoding the human mind. "We cannot begin later than the hunter-gatherers," he maintains. "Hunting fuelled an expensive brain, put us in an arena where intelligence brought better returns and, by concentrating resources, gave rise to social interaction, between peers and between the sexes."
While he concedes that not every human impulse can be forced through the evolutionary sieve, Pinker insists that human emotions typically categorised as irrational may instead be viewed as "goals of the device" - the device being us - competitive humans. "Different goals are turned on depending on the situation - fear, for example, which is designed to keep our bodies out of harm's way, or disgust which is designed to keep us free of biological contaminants."
But how are selfless emotions such as generosity explained? As paradoxical tactics, says Pinker. Generosity may have originated in the hunter's observation that sharing his kill with allies ensured that they would share their next meal with him. Even the most irrational state of all - romantic infatuation - is cunningly reassessed by Pinker as a tactic. "Romantic love is a promise operating with the same logic as a threat," he contends. "To make that promise credible it is useful to make yourself appear less likely to talk yourself out of a state over which you have no control, to appear helpless."
Recently married for the second time and evidently for love, Pinker adds that "love and generosity can be sincere in the individual, even if they are cynical in evolutionary terms. They can be heartfelt in the organism."