ILLNESSOPEDIA

Faces 'primarily differentiated by race and gender,' study shows

Researchers from Harvard University say they have uncovered neurological patterns in the brain that play a part in differentiating people's faces, and according to their new study, our brain primarily recognizes faces by race and gender.

According to the researchers, previous studies have shown that a part of the brain known as the fusiform face area (FFA) - a region in the visual system situated in the fusiform gyrus - plays a part in face recognition by extracting the "physical information" that distinguishes the faces of different people 200 milliseconds after seeing them.

But the researchers wanted to analyze the patterns involved in the FFA process and find out how this region of the brain differentiates between faces.

For their study, published in the journal PLOS One, the research team analyzed 17 college students and community members from Cambridge, Massachusetts. Of these, nine were female and eight were male.

Researchers say the brain patterns in the fusiform face region (FFA) of the brain show that we primarily differentiate faces by race and gender. Image credit: Juan Manuel Contreras.

The participants were required to undergo functional magnetic resonance imaging (fMRI) in order for the researchers to monitor changes to blood flow in the brain.

While in the scanner, participants were shown images of young adults, who were facing forward with their mouths closed. The subjects were then required to categorize the faces by gender (male or female) or by race (black or white).

Race, gender determined early

Results of the fMRI revealed that the FFA appeared to play an important part in differentiating faces through race and gender. Patterns of activation in this brain region were different for black and white faces, and for female and male faces.

When the participants were instructed to focus only on the sex of a person, the scans revealed that the FFA was still recognizing the race, and this was the same when they were asked to focus only on the race of a person.

Juan Manuel Contreras, of the Department of Psychology at Harvard University, explained these results to blog:

"We discovered that fusiform face area differentiates faces by sex and race. Specifically, patterns of neural activity here distinguish between men and women, and they distinguish between the faces of black and white people.

We did not find any other brain region in the visual system that can do this - even other brain regions involved in face perception - suggesting a unique role for fusiform face area in perceiving the sex and race of faces."

Furthermore, the researchers say that because these patterns were found in the FFA, this suggests that differences in race and gender are determined early in a person's visual perception.

But Contreras says it is important to note that previous research suggests the FFA does not link visual perception with meaning:

"It probably does not know anything about sex and race. It's simply a brain region in the visual system that sees faces as belonging to two different sets."

"The information is simply being gathered, and is then handed off to other parts of the brain that begin to process what those differences mean - other regions that have information about what men and women are like or what it means for a face to belong to a black person or a white person."

'Critical' for us to know gender and race of people

The researchers hypothesize that the reasons behind the FFA identifying gender and race as a first port of call is that, possibly due to developmental or evolutionary reasons, a person deems it important to know the gender and race of other people.

Contreras told blog:

"It is often critical for us to know the sex and race of the people with whom we interact.

Our research identifies a brain region that aids in this act of social perception, but it does not tell us whether our brain works this way for evolutionary reasons - whether we are born this way - or whether we develop this way during a lifetime of viewing faces of men and women from different races."

Contreras said that future research will examine how information regarding the gender and race of faces moves from the FFA to other areas of the brain involved in linking visual stimuli with meaning, such as brain regions that process stereotypes as found in previous research.

blog recently reported on a study that suggested men with wide faces trigger selfishness in others.