Testosterone, Male Sex Hormone, Also Makes Guys Honest

Sex hormone makes men more aggressive, but also conscious of their image.

ByABC News
October 16, 2012, 7:34 PM

Oct. 17, 2012 — -- Testosterone, the bad boy among sex hormones, has a sweet side. Researchers in Germany report they have found that the stuff that makes men aggressive and confrontational also makes them less likely to lie.

The surprising discovery flies in the face of all that we have been told about testosterone for the past few decades. It's why a guy is more likely than a gal to punch someone out in an effort to prove himself manly, or the baddest dude in the bar. Women have testosterone too, but not nearly as much as men do.

Recently, however, scientists have challenged the view that the hormone is the root of all evil. No one is saying it doesn't play a major role in male sexuality. But a number of scholars now think that's not all there is to the story.

"Popular perceptions of the effect of testosterone on 'manly' behavior are inaccurate," Pennsylvania State University researchers concluded in a recent study. "We need to move away from such simplistic notions by treating testosterone as one component along with other physiological, psychological and sociological variables in interactive and reciprocal models of behavior."

In other words, there's a lot more going on here than one hormone making guys act like jerks in an effort to impress the ladies.

Much of the misperception probably lies in the fact that much of what we thought we knew about testosterone came from animal studies. Castrated rats, for example, became meek when deprived of the hormone. But when scientists gave them a shot of testosterone, they were ready to fight.

But there's a lot of difference between humans and rats. As scientists are now pointing out, the human social system is a very complex matrix of interactions and reactions, quite unlike the world of the rat.

Researchers at the University of Bonn have added significantly to the changing view of testosterone by carrying out a clever experiment to see how the hormone affects honesty. According to the old image, you would think men would be willing to lie more while cruising on an enhanced level of testosterone if it proved rewarding. But that turned out not to be the case.

The researchers recruited 91 young men for a two-day experiment. On the first day, each participant had gel containing testosterone rubbed on his upper arm. About 24 hours later, after the hormone had enough time to be absorbed by the body, the men returned to the lab. About half the participants had received a placebo, not testosterone.

Each participant was seated in a private booth and told to roll a six-sided dice repeatedly and record the number facing up each time. They would be rewarded financially based on the numbers -- one Euro for 1; two Euros for 2, and so forth, except for the number 6. They would get nothing for a number 6.

No one else was present. Each man was alone; absolutely no one would know if he was cheating. Even the researchers were unable to monitor the activity. So how did they learn that participants were less likely to lie if given testosterone? The answer is in the details.

Since rolling dice produces purely random results, the participants who received a placebo should have ended up with essentially the same tally as those who were hyped up on testosterone.