Levels of hormone exposure in the womb helps determine which academic discipline researchers work in, a new study suggests. Perhaps surprisingly, a “female” pattern of exposure was common in scientists, while a “male” pattern dominated in the social sciences.
The survey compared the length of people’s index (first) fingers with their ring (third) fingers. This comparison is thought to indicate prenatal sex hormone exposure, probably because some developmental genes control the formation of both the reproductive system and the digits.
In the general population, men have a “digit ratio” of 0.98 on average – the index finger being slightly shorter than the ring finger. Women have a digit ratio of 1.0 on average, meaning the two fingers are the same length.
However the 107 male and female academics surveyed at Bath University, UK, had very similar ratios – 0.987 for men and 0.984 for women. This suggests the two groups were exposed to the same levels of oestrogen and testosterone in the womb.
Hormone levels also appear to predict which discipline researchers work in. Staff in the departments of chemistry, computer science, mathematics and physics all had average ratios of over 0.995 – close to the female average – despite 81% of those subjects being male.
In contrast, the staff of the social science departments of economics, education, management, social and policy sciences had an average ratio below 0.98, the male average, despite only 66% of this sample being male.
“It’s unnerving to think the profession I’m in was determined by the hormones I was exposed to in the womb,” says Mark Brosnan, the lead author from the University of Bath, UK, whose work has been submitted to the British Journal of Psychology.
John Manning, an expert on digit ratios from the University of Central Lancashire, is not surprised that hormone levels in the womb can have such an influence. “The effect of testosterone on the developing brain is organisational and permanent,” he says.
Here is the full story. In case you are wondering, one of my hands fits this story and the other does not.