Study: No evidence that testosterone reduces cognitive empathy

PanARMENIAN.Net - It's long been known that autism is far more prevalent in males than in females. What hasn't been understood is why.

"Of course, the primary suspect when we have something that is sharply differentiated by sex is testosterone," says Gideon Nave, an assistant professor of marketing in Penn's Wharton School.

Yet a new study led by Nave implores scientists to keep looking. In two randomized controlled studies of testosterone administration which were the largest of their kind and included nearly 650 men, Nave and colleagues found no evidence of a link with cognitive empathy, the capacity to read the emotions of others, a trait that is characteristically impaired in people with autism, Medical Xpress says.

They report their findings in the journal Proceedings of the Royal Society B: Biological Sciences.

"Several earlier studies have suggested a connection between testosterone and reduced cognitive empathy, but samples were very small, and it's very difficult to determine a direct link," says Amos Nadler of Western University, the first author of the study. "Our results unequivocally show that there is not a linear causal relation between testosterone exposure and cognitive empathy."

Prior to this work, the strongest evidence for a link between testosterone exposure and reduced cognitive empathy came in 2011 in a study that found administering testosterone to healthy women reduced their performance on a test of reading emotions. The results suggested the testosterone impaired their performance. Moreover, the work pointed to the ratio of the length of the participant's second finger to their fourth finger, known as the 2-D:4-D ratio, as a proxy for sensitivity to testosterone. Some believe that the ratio declines with increased in utero exposure to testosterone, though evidence for that connection is mixed.