Researchers at Harvard University have found a region of the brain where neural patterns changed when test subjects viewed either a male or female face. The researchers used real-time scans of the brain during testing where facial images of men and women were shown to test subjects.
Manual Contreras, the lead author of the study who recently earned a Ph.D. at Harvard, states, “We found that a region called the fusiform face area seems to play a key role in differentiating faces. When we studied the patterns of activation in the region, we found they were different for female and male faces.”
Similar differences in brain activity were found when tests subjects were shown facial images of people of different races.
The authors speculate that in evolutionary terms, individuals who could more quickly determine the gender or race of the person they came in contact with, had a better chance of survival. “Sex and race can be important things to know about another person,” Dr. Contreras said. “So it would make sense that as soon as you see another person, you need to figure out the social categories to which they belong.”
The article may be viewed here.
In evolutionary terms race did not really exist, it is a modern concept. Racial differences, as we understand them, are mostly climatic adaptations enhanced by somme selective breeding brought about by separation of small populations. There are lots of reasons why, not recognizing but being able to read differing male or female expressions could be useful, but race was not much of an issue until comparatively recently in human history.Tribal membership, once we got that far, could also be important, but the likelihood is that sex and being able to read the opposite sex was even more important then than it is now.