An experimental study in China found that giving a single dose of testosterone gel to healthy men improved how quickly they learned to perform prosocial tasks compared to the group given a placebo. The study was published in Biological Psychology.
Testosterone is a major sex hormone in men. It is produced mainly in the testicles, but also in the cortex of the adrenal gland. It plays a key role in the development of the male sex organs, but also produces a number of other effects on the body. At puberty, it causes the appearance of facial and pubic hair, an increase in the size and strength of muscles and bones, and a deepening of the voice. Testosterone plays an important role in regulating libido, but also contributes to baldness in the last years of life.
Studies have linked higher testosterone levels to increased aggression in animals. The link between testosterone and aggression in men is less clear. A meta-analysis of human studies reported a positive association between testosterone levels and aggression, but the magnitude of this association is virtually negligible.
Recent studies have indicated that testosterone may also induce prosocial behavior, such as making people more likely to offer fair deals or cooperate better with others during competitions. To explain this link, scientists have proposed the so-called “social status hypothesis” which suggests that testosterone promotes appropriate behaviors to achieve and maintain social status. Thus, the effects of testosterone on behavior would be context-dependent.
Study author Xin Wang and his colleagues wanted to test the social status hypothesis of the effects of testosterone. They reasoned that, if this hypothesis is correct, participants who received testosterone would increase their learning rate for a task that increases their social status. To test this, these researchers designed an experiment.
The participants were 120 healthy men. Their average age was 21 years old. They were asked to abstain from drinking alcohol, caffeine and smoking for 24 hours before the test session. They were randomly divided into two groups.
One group had testosterone gel applied to their shoulders and upper arms at the start of the experiment by an assistant. A placebo (a similar-looking hydroalcoholic gel without testosterone) was applied to participants in the other group. Neither the participants nor the assistant applying the gel knew which gel they were applying.
Participants completed a series of prosocial learning tasks. As part of these tasks, participants had to choose between one of two symbols. One of the symbols had a high probability of reward and the other had a low probability of reward. The learning consisted of participants recognising, through trial and error, which symbol is most often associated with the reward and starting to prefer that symbol.
There were three types of test situations. In the first, participants were notified that they would receive whatever rewards they won. In the second situation, the rewards would go to another person, while in the third situation, the rewards would go to no one (control).
The results showed that the group that received the testosterone gel learned faster in all three types of situations. Participants in the placebo group learned faster in situations where they expected to receive the rewards themselves compared to situations where they earned the rewards for another person or for no one. However, participants in the testosterone group learned just as quickly when they earned rewards for themselves and when they earned them for another.
In the testosterone group, learning was faster in the situations where they earned rewards for themselves and when they earned for another person, compared to the situation where no one received the rewards (earning rewards for l ‘computer). In the placebo group, learning was faster when participants earned rewards for themselves than for no one. There was no difference in learning speed in the placebo group between situations where someone else received the reward and those where no one received it.
“In summary, using exogenous testosterone administration and the prosocial learning task, we found that testosterone could facilitate prosocial behavior when there was no conflict between self-interests and others. Moreover, testosterone also improved reward sensitivity, highlighting the role of testosterone in reward processing and decision making,” the study authors concluded.
The study makes a valuable contribution to scientific knowledge about the effects of testosterone on male behavior. However, it must be taken into account that the sample consisted exclusively of young men. Results on men of different ages may not be the same. Additionally, researchers have focused only on testosterone, while studies have shown that its effects on behavior depend on interactions with other hormones.
The study, “Can testosterone modulate prosocial learning in healthy men? A double-blind, placebo-controlled testosterone administration study,” was authored by Xin Wang, Jiajun Liao, Yu Nan , Jie Hu and Yin Wu.