Story of Psychology - Morton Hunt [241]
A very different source of evidence consists of the actual testing of hypotheses derived from evolutionary theory. Here’s an example. First, start with a well-supported observation: Men give higher priority to physical appearance than do women in the selection of a mate. Next, generate an evolutionary hypothesis to account for this: Women’s physical appearance was a clue to ancestral man as to fertility. Finally, test the hypothesis: Show male volunteers a variety of pictures of women with varying waist-to-hip ratios and ask their preferences. The result: Men find women with a low waist-to-hip ratio—a known fertility correlate— attractive, apparently a preference built in by evolution.48
Another: Sexual jealousy, though common to both sexes, has been shown by studies to be activated in men far more than in women by signs of sexual infidelity rather than emotional infidelity. Evolutionary psychologists see this as an adaptation that originated in ancestral males’ uncertainty of parenthood, which was less an issue for ancestral women.49
Still another genre of evidence: laboratory tests of built-in fears. In a series of studies, some participants were asked to find such phobia-related images as spiders and snakes embedded in pictures filled with nonfear images such as flowers and mushrooms. Other participants were asked to find nonfear images embedded in pictures filled with phobia-related stimuli. People in the first category found the spiders and snakes significantly faster than people in the second category found the flowers and mushrooms, and the difference held true no matter how confusing the array of images and no matter how many distractions such as noises and interruptions were introduced.50 As Buss says, “It was as if the snakes and spiders ‘popped out’ of the visual display and were automatically perceived.” Yet objects that are products of modern life and that are as dangerous as snakes do not automatically trigger the same kind of attention: we fear snakes and not electrical outlets, for example, because electrical outlets are too recent an invention to have become objects of built-in fear response.51
Again: Why is cautiousness and fearfulness far more common than boldness and bravery? Because, according to evolutionary psychology, it’s more adaptive: Our cautious ancestors were more likely to survive and procreate than our bold ancestors.
Why do most human beings tend to conform to the beliefs and behaviors of their own group? Because of a built-in desire to reduce uncertainty, which leads us to see ourselves as members of our group (even in an individualistic culture).
Why do men have better spatial ability than women? Because primitive males were the hunters, and those of them with superior spatial ability had a better chance of survival and progeny creation; women were not subject to the same selective force.
Why do human beings have an apparently innate need for self-esteem? For several reasons, according to evolutionary psychologists. For one thing, self-esteem derives in part from the esteem and respect in which one is held by others; hence behavior that tied the individual in closely to his or her group—and so improved the group’s chances of survival—was selected by evolution and became a human tendency. Again, an accurate level of self-esteem was a guide to one’s status and security in the social hierarchy; too low or too high a self-evaluation lessened the individual’s chances of survival. Finally, self-esteem was a valuable mechanism in the mate-selection process, success in which was essential to pass on one’s genes; the individual with no self-esteem tended to be weeded out by evolution.
And so it goes, on and on. At times, the evolutionary psychologists sound as if