Wednesday, 18 April 2007

Pre-Natal Hormones and Post-Natal Cognition

From :

In one of the first research studies to assess sex differences in cognitive performance in nonhuman primates, researchers at the Yerkes National Primate Research Center have found the tendency to use landmarks for navigation is typical only of females.

This finding, which corroborates findings in rodents and humans and is available in the online edition of Hormones and Behavior, suggests there is not just a difference in how well females and males solve spatial problems, but also in which types of cues they use to solve such problems. Researchers are applying this knowledge to gain a better understanding of how the brain develops and functions.

Lead researcher Rebecca Herman, PhD, says the very fact females and males use different strategies suggests there are subtle sex differences in the way the brain develops. As an example of these strategies, Herman said men, when finding a location, generally use north and south as well as distance estimates whereas women prefer physical cues such as street names, signs and buildings.
All animals were studied once they reached adulthood. Researchers observed as the monkeys navigated an open area to locate highly valued food items in goal boxes. The researchers varied the consistency of the food locations (spatial information) and the presence of colored markers (landmarks) on baited goal boxes so they could assess the monkeys’ memory and use of spatial arrangement and markers.

"When both spatial and marker cues were available, performance did not differ by sex or prenatal treatment," said Herman. "When salient landmarks directly indicate correct locations but spatial information is unreliable, females perform better than males," she continued. “Male subjects whose testosterone exposure had been blocked early in gestation were more able to use the landmarks to navigate than were control males. They performed more like females. This suggests that prenatal testosterone likely plays a role in establishing the sex difference in using landmarks for navigation," said Herman. The researchers’ next steps are to study if males’ performance differs as their circulating testosterone levels change normally.
I think it will, based on my own experience. Even before we knew what was happening, I recorded differences like this. I find it remarkable though that this is not a characteristic of H.Sap, but in Primates in general. The way our brain-structure is sexually dimorphic - gendered - appears to be embedded deep in our evolutionary tree. It could be that instead of the social ordering of females as gatherers and males as hunters leading to the evolution of congnitive specialisation, but that the social ordering was already hard-wired in us from ancestors far more distant than the proto-chimpanzee that human, bonibo and forest chimps are all descended from.

1 comment:

mythusmage said...

The question now arises, do male chimps ask for directions? :)my