Too much testosterone blights social skills
May 12, 2004
Levels of testosterone in the womb may have profound effects on a person's social development. The findings might also explain why men are four times as likely as women to suffer from autism.
The study is the latest in a series on a group of 58 children born in 1996 and 1997. Simon Baron-Cohen's team at the Autism Research Centre in Cambridge, UK, measured testosterone levels in the amniotic fluid of the babies' mothers while pregnant. This is presumed to reflect levels in the babies themselves.
The team has already found that the babies with higher fetal testosterone levels had a smaller vocabulary and made eye contact less often when they were a year old. And a study by another group has shown that eight-year-old girls who had high fetal levels of the hormone performed better at tasks such as mentally rotating a two-dimensional figure.
All this fits with Baron-Cohen's theory that high fetal testosterone levels push brain development towards an improved ability to see patterns and analyse systems tasks males tend to be better at. But it also impairs communication and empathy which are usually more highly developed in females (New Scientist, 24 May 2003).
Now his group has looked at the original 58 children again, at age four. The researchers asked the mothers to fill in questionnaires on their child's interests and social development. The children with higher testosterone in the womb are less developed socially, and the interests of boys are more restricted than girls, the team will report in the Journal of Child Psychology and Psychiatry.
As Baron-Cohen admits, the study is too small to prove his ideas are right. "You'd need much stronger data to conclude that there is a reliable relation between fetal testosterone and social competence," says Alison Gopnik, an expert in child cognition at the University of California, Berkeley.
Baron-Cohen has already begun another study involving hundreds of children. He hopes this will also provide insight into the development of autism. His hypothesis is that autism is an extreme form of the male brain. Sufferers are typically poor communicators, but often extremely good at tasks involving pattern recognition.
If his ideas are right, very high testosterone levels might be to blame for some cases of autism, but Baron-Cohen refuses to jump the gun. "Until we demonstrate a link between autism and fetal testosterone, we cannot talk about causation," he says.