Testosterone and Your Impulses

It's a time-worn trope of TV and film: the macho, impulsive Man of Action who shoots first, asks questions later and lets the chips fall where they may. It turns out that there may be some science to go along with all that shooting-from-the-hip in the movies.

New research shows how higher levels of testosterone increase the tendency in men to rely on their intuitive judgments and reduce the decision-making process by which a person stops to consider whether their gut reaction to something makes sense. Half of a group of test subjects were given a dose of testosterone while the other half were given a placebo, then both halves were given a brain teaser as a test of their cognitive reflection. A small cash incentive was promised for providing the correct answer. The researchers found that men given doses of testosterone performed more poorly than the control group.

"What we found was the testosterone group was quicker to make snap judgments on brain teasers where your initial guess is usually wrong," says Caltech's Colin Camerer, the Robert Kirby Professor of Behavioral Economics and T&C Chen Center for Social and Decision Neuroscience Leadership Chair. "The testosterone is either inhibiting the process of mentally checking your work or increasing the intuitive feeling that 'I'm definitely right.'"

In fact, the results show that testosterone group scored significantly lower than the placebo group – on average answering 20 percent fewer questions correctly. They even underscored their Saturday Matinee Masculinity by giving incorrect answers more quickly, and correct answers more slowly than the placebo group. The researchers concluded that the results "demonstrate a clear and robust causal effect of [testosterone] on human cognition and decision-making.”

What's the science? The phenomenon they've observed can be linked to testosterone's effect of increasing confidence in humans, the researchers believe. Testosterone is a hormone that has always been connected to an enhanced male drive for social status, and recent studies have shown that confidence enhances status.

"We think it works through confidence enhancement. If you're more confident, you'll feel like you're right and will not have enough self-doubt to correct mistakes," Camerer says.

The research is scheduled to be published in the journal Psychological Science.