Testosterone lowers social intelligence.

Understanding a person’s emotional state from his or her body language and facial expressions is an essential skill in social interaction. You can find out how adept you are at reading people’s mind from their facial expressions by taking the “Read the mind in the eyes” test (RMET). Not entirely surprisingly, women tend to fare much better than men on this test. In fact, when I asked a few friends to take this test for me, I noticed that, on average, the women got a higher score than did the men. Results like these suggest that women are more “cognitively empathetic” than men, i.e., women are able to read a person’s emotions from their body language better than men. So what makes women more emotionally perceptive than men? Clues emerge from a recent study published in the Proceedings of the National Academy of Sciences.

Led by Dr. Simon Baron-Cohen, a team of researchers from The Netherlands, South Africa and the UK asked whether testosterone, the “male-type” hormone, could directly cause a reduction in cognitive empathy. They assessed this by asking sixteen women to take the “Read the mind in the eyes” test after taking either a placebo or a dose of testosterone. Neither the women nor the scientists knew at the time of the experiment whether a woman was getting the placebo or testosterone, thus reducing any biases that could be introduced into the results. The scientists observed that when given testosterone, 75% of the women performed significantly worse on the RMET test than when given a placebo. This suggested that testosterone could directly reduce a person’s cognitive empathy. They also noticed that some women’s cognitive empathy was more affected by the testosterone than others. The researchers hypothesized that this difference may be attributable to the amount of testosterone the women were exposed to as foetuses, while still in their mother’s womb. So the scientists used a convenient measure of fetal testosterone, the ratio of the length of the index finger to the length of the ring finger on the right hand (2D:4D), to test their hypothesis. Previous studies have shown that foetuses exposed to higher levels of testosterone have smaller index to ring finger length ratios (lower 2D:4D ratio) than foetuses exposed to lower levels of testosterone. In fact, men have a lower 2D:4D ratio than women. The researchers noticed that women with a low 2D:4D ratio (so those who had been exposed to higher testosterone levels as foetuses) were the ones who performed poorly upon getting testosterone. On the other hand, women with high 2D:4D ratios did just as well when given testosterone as when given placebo. Based on these results, the authors of the study suggest that fetal testosterone moulds the brain in such a way, that re-exposure to testosterone as an adult (like at puberty) can affect social intelligence and cognitive empathy. It’s no wonder then that men are less perceptive of others’ emotions than women!

However, the results of this work are more than just a caricature of men’s social intelligence. They also improve our understanding of conditions such as Autism and Asperger syndrome, where social intelligence is highly compromised. In fact, the RMET test was first developed by Dr. Baron-Cohen to study Autism spectrum disorders. By understanding how hormones such as testosterone can affect one’s ability to perform on this test, we can garner a better understanding of the causes of the behavioural aspects of Autism and hopefully even find clues to treat these disorders. In fact, a recent study showed that the “female-type” hormone oxytocin could improve the performance of male boys with Asperger syndrome on the RMET test, thus making them more emotionally perceptive. Therefore it will be interesting to better understand the role of testosterone in mediating social intelligence and determine if the hormone plays a similar role in other aspects of human behaviour.


1 Comment

Filed under Biology, Psychology

One response to “Testosterone lowers social intelligence.

  1. zach

    ironically, his cousin (this is true) sacha baron-cohen relies on people’s perceptions (or lack there of) to make his living also.

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