More testosterone reduces empathy

CAMBRIDGE, England, Feb. 9 (UPI) -- Administrating testosterone adversely affects a person's ability to infer what another person is feeling from eye expressions, British and Dutch experts say.

Professors Simon Baron-Cohen at the University of Cambridge in England and Jack van Honk at the University of Utrecht used the "Reading the Mind in the Eyes" task as the test of mind reading, or how well someone can infer what a person is thinking or feeling from photographs of facial expressions from around the eyes.

Mind reading is one aspect of empathy, the researchers say.

The study involved 16 young women from the general population -- women on average have lower levels of testosterone than men -- who were administered testosterone under the tongue.

The study, published in the journal Proceedings of the National Academy of Sciences, found not only did that administration of testosterone lead to a significant reduction in mind reading, but that this effect is powerfully predicted by the 2D:4D digit ratio -- a marker of prenatal testosterone.

The findings suggests why on average women perform better at reading feelings than men and that the digit ratio (2D:4D), a marker of fetal testosterone, predicts the extent of later testosterone.

Given that people with autism have difficulty in mind reading and that autism affects males more often than females, the study provides further support for the androgen theory of autism.