Wondering why your husband is often more cynical or distrusting than you? Blame it on his higher level of testosterone. Scientists say increasing testosterone levels reduces interpersonal trust.
Researchers at Cape Town University found that testosterone supplements given to women appeared to “harden them up,” make them less open and less trusting. Those involved in the study believe men over time required more testosterone, which makes men physically strong and aggressive, and also helps them be wary of danger or unscrupulous individuals. Women, on the other hand, have been socialized to be more cooperative and helpful to others.
The findings were published recently in Proceedings of the National Academy of Sciences. Dr. Jack van Honk, a psychologist at Cape Town University, said that testosterone increases social vigilance in order to prepare them for competition and fights for resources.
Researchers said: “In the same way that we have evolved capacities to help others, we have also evolved capacities to deceive and cheat. Thus, those who are willing to believe what others say, or fail to probe the motivations underlying their actions, may fall prey to considerable economic and social costs.”
“Consequently, testosterone increased social vigilance in trusting humans, presumably to better prepare them for the hard-edged competition over status and valued resources.”
To test the theory, researchers gave testosterone pills and dummy pills to 24 women aged about 20 and then asked them to rate the trustworthiness of strangers’ faces on a scale from -100 (very untrustworthy) to +100 (very trustworthy).
The half of volunteers who rated faces as most honest after the placebo scored the photographs an average 10 points – or five per cent – lower after ingesting testosterone. In other words, the volunteers became less trusting after taking the testosterone, but not after taking a placebo. Read more about the testosterone study.
These results may give you some insight into the different social interactions you and your spouse have with others. It may also help you understand why men may be less trusting of others, while women may be more trusting. Don’t be so quick to judge one another, as our hormonal regulation may be at play in assessing our environment and others around us.
On the other hand, some of us have been hurt by others we have trusted. So the “school of hard knocks” may have also made us less trusting. Which do you think causes more distrust—our experiences or our biology?
Does this research surprise you? Do you find you and your spouse have different levels of trust or cynicism?