THE STUDY
"Physiological Effects on Demography: A Long-Term Experimental Study of Testosterone's Effects on Fitness," published in the May issue of The American Naturalist.
THE PROBLEM
Does an extra dose of testosterone pay long-term dividends? A higher level of the hormone increases sex drive and attractiveness of males, leading to more offspring and increased evolutionary fitness; it also weakens the immune system, amplifies stress, and encourages recklessness, increasing the risk of departing the gene pool altogether. Looking at songbirds, Wendy Reed, a physiological ecologist at North Dakota State University, set out to determine whether, evolutionarily speaking, a little extra machismo is really worth it. And since testosterone has pretty much the same effect across all species, her results probably extend to humans as well.
THE FINDINGS
A group of Reed's colleagues went to the Appalachian Mountains to jolt the testosterone levels among breeding males in a population of small, two-toned ...
