Testosterone decreases the activity of the temporoparietal junction, a region of the brain involved in empathy.
- In one experiment, participants who received a testosterone supplement were found to be less generous to strangers.
Generosity is a question of hormones. This is the conclusion of a study conducted by Swiss and Chinese researchers recently published in the journal Proceedings of the National Academy of Sciences (PNAS) who argues that high testosterone levels are correlated with less generous and more selfish behavior.
Two choices: get rich or benefit the other?
Previous research has shown that high levels of testosterone in men can lead to changes in decision-making, antisocial behavior, damage to romantic relationships, and in some cases, an increased desire for material possessions. As a reminder, testosterone is a hormone mainly produced, in men, in the testicles and the adrenal glands. This hormone is also produced in women by the ovaries, in smaller quantities.
Researchers conducted several experiments in male volunteers to investigate the link between testosterone levels and generosity. For this, they separated the 70 volunteers, aged 18 to 25, into two groups: one using a gel containing 150 milligrams of testosterone and the other a placebo gel based on water and alcohol. Each of the participants had the gel applied to their upper arms and shoulders. The scientists then asked all the volunteers to rate the social closeness they have with several people, ranging from family members to complete strangers. The researchers gave them a sum of money that they had to either keep or share with the people concerned. Meanwhile, the researchers analyzed the participants’ brains using functional magnetic resonance imaging (fMRI).
More selfishness towards the people you feel least close to
Analysis of the results showed that the volunteers gave about the same to the people they feel close to. But when it came to distributing the money for people less close, those who received testosterone proved to be less generous. In detail, the researchers observed differences in activity in the temporoparietal junction, a region of the brain involved in empathy. “Testosterone is associated with aggressive behavior in animals and humansthe researchers concluded. Here, we link increased testosterone to selfishness in economic decision-making and identify the neural mechanisms by which testosterone reduces generosity. We find that testosterone induces more selfish choices, especially when other distant people are involved..”
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