While he was still in graduate school, psychologist Frank Muscarella started thinking about male pattern baldness.
Muscarella wasn't worried about his own hair, which was thick and dark. He wondered why a small percentage of men start to lose their hair in puberty and are pretty much completely bald by the time they're adults.
The answer, he suspected, had something to do with evolution.
Until perhaps the 1950s, most scientists who thought about the problem would probably have said that baldness was a medical problem, like bad breath or cancer. The notion that it served some purpose - that evolution had made some men bald - might have seemed absurd.
But then, a new generation of Darwin's disciples began to rethink his theories in the light of the emerging science of genetics, and to use both ideas to study traits - everything from aggression and creativity to body odor and baldness - and how they might be related to human behavior and society.
Today, the very idea of evolution is under assault from creationists, or others who think life is the product of "intelligent design." But supporters of evolution are themselves engaged in a fierce debate over Darwin's theory that could have profound implications for the way we think about ourselves and our world.
Almost a century and a half after Darwin first published his ideas, scientists are bitterly split over whether the theory can be applied far beyond the worlds of fossils and museums, into the realms of psychology, economics, art, literature and even religion.
Take baldness, for example. Muscarella and a colleague, Michael R. Cunningham, suspected that evolution could help explain it. So they showed pictures of men with a lot of hair, men with a little hair and men with no hair to a group of women and asked them to describe what they saw.
Although the women found the bald men less attractive, they also described them with words like "nonthreatening," "intelligent," "influential" and "approachable."
Muscarella and Cunningham theorized in a 1996 paper in the journal Ethology and Sociobiology that the first men who suffered male pattern baldness appeared older and wiser than their years. "Think of how priests shave their heads, about how we talk about the egg-headed professor," said Muscarella, a professor at Barry University in Florida, in a phone interview.
