The Genetic Temptation
A gene for social skills, we are told, has now entered the fast growing Pantheon of genes "for" various human behaviors and dispositions--taking its place alongside genes for risk-taking, happiness, aggression, and sexual orientation, among others. One gets the impression that we are well on the way to figuring ourselves out, and that we are far simpler than anyone imagined. After all, adeptness at cocktail party conversation--or addiction to the cocktails--may be no less genetically determined than hair color.
Defining the role that genes play in behavior, however, is not so easy. Many of the results of human studies are highly preliminary and do not actually identify a gene. In fact, they cannot, for genetic experimentation on humans is impossible. Even in animals whose genes are more easily studied and much better understood, such as Drosophila , the tiny fruit fly, there is no simple one-to-one correspondence between gene and behavioral trait. Instead, a wide variety of genes influence each characteristic.
Fruit fly genes are surprisingly similar to ours--as they are to those of most other creatures. Even many aspects of their behavior resemble our own. For example, when training a fruit fly to prefer one odor to another in a simple learning task, it will remember better if trained at repeated intervals over a long time rather than in one intense session. Fruit flies are not geniuses, but "cramming" works no better for them than it does for us. Even more recently, scientists at the Neurosciences Institute in San Diego have shown that according to all essential definitional criteria, fruit flies sleep at night.