From My latest Mind and Matter Column at he Wall Street Journal:
The science of evolutionary psychology has flourished in recent years by asking "why" as well as "how" questions about animal and human behavior, and answering them with historical explanations.
For example, why are most male mammals keen on promiscuity, while most female mammals are keen on picking high-status mates? Because-given that fertilization takes seconds, while gestation and lactation take years-mammals are often descended from philandering males or females that chose resource-holding mates, but not so often from promiscuous females or choosy males.
Evolutionary psychologists are now turning their attention to more culturally variable cognitive conundrums. Hypocrisy and self-deception, for example. Last year Robert Kurzban of the University of Pennsylvania published a book called "Why Everyone (Else) Is a Hypocrite," and this month Robert Trivers will publish a complementary explanation of self-deception in his book "The Folly of Fools."
The Kurzban theory of hypocrisy takes as its starting point that the mind is modular. That is to say, just as the body uses different organs to achieve different ends-bones, kidneys, skin and nerves each being designed for different jobs-so the brain uses specialized mental circuits honed for tasks like vision, social interaction and fear. Mr. Kurzban uses the parallel of the smartphone. Different apps are built for different jobs.
If the mind is modular, says Mr. Kurzban, then sometimes the modules will contradict each other. The hunger module will demand a cheeseburger, while the vanity module demands a diet. People break New Year's resolutions because willpower is just one module, up against some formidable mental rivals. Eliot Spitzer's moralistic module led him to condemn prostitution; his lust module chose a different path. Presumably, we disapprove of hypocrisy because we have a fairness module: We demand that others practice equal treatment, and we see their hypocrisy as evidence that they exempt themselves from their own rules.
Mr. Kurzban says there is no reason to expect consistency from a modular mind. "A foolish consistency," said Emerson, "is the hobgoblin of little minds." This leads him to the conclusion that self-deception comes about not for some holistic purpose such as "protecting the self" from damage to self-esteem (as many psychologists have argued) but simply because it serves the purpose of one module to deceive another. In his view, we deceive ourselves as a sort of public-relations exercise: so that we project a particular perspective to the outside world.
Indeed, because there's no such thing as a unified self, just a collection of modules, the very phrase "self-deception" is misleading in the author's view. It's more accurate to say that many of our conscious beliefs are "strategically wrong." In a remarkable experiment done at the University of Georgia in the 1990s, heterosexual men with strongly homophobic views were more physiologically aroused by gay pornography than heterosexual men with more neutral views. There was no difference with straight porn.
Mr. Trivers takes further this idea of hiding potentially damaging information away in an unconscious bit of the brain where it cannot leak, arguing that we deceive ourselves the better to deceive others. In one experiment, people were quicker to spot a picture of themselves if it was enhanced to be slightly better looking, and slower if it was made uglier. Given that much human communication is essentially manipulative in motive-hoping to make people like us, for example-it's not a bad idea to begin by manipulating ourselves.
Which may explain why Mr. Trivers finds that intelligent people are more likely to deceive themselves than the average. More than 90% of professors think they are in the top half of their profession.