Testosterone is a well-known male hormone which affects many aspects of a man’s life, but it may also play a part in altering social behavior, including lying. Men who have more of the hormone seem to lie less frequently than those who have lower levels, according to Professor Dr. Armin Falk, from the University of Bonn, and colleagues.

A recent study, which was published in PLoS ONE, revealed that in “make-believe” circumstances, individuals who were administered testosterone lied significantly less than those who were given a placebo.

Testosterone is a hormone which stimulates male characteristics, including muscle building, sex, and libido. The hormone is also found in women, but the levels are much lower.

A 2008 study suggested that there is a link between testosterone levels and financial risk taking behaviors.

Professor Dr. Bernard Weber, a neuroscientist from the Center for Economics and Neuroscience (CENS) at Bonn, said: “Testosterone has always been said to promote aggressive and risky behavior and posturing.” However, new evidence shows that testosterone influences social behavior.

The disadvatages of many studies are, however, that they only correlate their subjects’ testosterone level with their behavior, said lead author of the study Dr. Matthias Wibral. He continued that this method solely displays evidence taken from statistics and does not explain the reasons for the men’s behaviors.

He explained: “For testosterone does not only influence behavior; behavior, in turn, also influences hormone levels.” The researchers from CESN decided to find a technique which would permit understanding of cause and effect.

Ninety-one healthy males were involved in the new behavioral investigation. Of these men, 46 had a testosterone gel applied to their skin, while the other 45 were given a placebo gel.

The day after the testosterone group received their gel, Bonn University Hospital endocrinologists analyzed whether testosterone levels in the blood were increased, compared to the placebo group.

In order to not alter the patients’ behavior, no one involved in the study knew who had been given which gel. Wibral explained: “Neither the subjects themselves nor the scientists performing the study knew who had received testosterone and who hadn’t. “

After the blood levels were measured, the researchers conducted behavioral tests. The subjects were asked to play a game of dice while in different booths. The higher their scores, the more money they received.

Professor Weber revealed:

“These experiments were designed such that the test subjects were able to lie. Due to the separate booths, nobody knew whether they were entering their real scores into the computer, or higher ones in order to get more money. Statistically, the probability for all numbers on the dice to occur is identical. So, if there are outliers in the higher numbers, this is a clear indication that the subjects have been cheating.”

The report noted that after the experiment the experts were able to determine whether the participants had cheated or were being honest.

The team involved in the trial analyzed the outcomes from the testosterone group as well as the placebo group.

Professor Dr. Armin Falk, a CENS co-director alongside Weber, explained that an increase in testosterone levels may boost pride among men and their ambition to portray a “positive self-image”.

Dr. Falk said:

“This showed that the test subjects with higher testosterone levels has clearly lied less frequently than untreated test subjects. This result clearly contradicts the one-dimensional approach that testosterone results in anti-social behavior. Against this background, a few euros are obviously not a sufficient incentive to jeopardize one’s feeling of self-worth.”

Lying is an act which is at best frowned upon and at worst seen as a serious sin in many cultures and religions around the world. Dr. Falk concluded: “However, lies play a great part both in the business world, as well as in personal life.”

When people lie, it is normally not solely to benefit themselves, but to help or “protect” someone else. The professor added: “However, there are very few studies on the biological causes of lying. In this regard, the study has allowed us to make a big step forward.”

Written by Christine Kearney