Human face-selective cortex does not distinguish between members of a racial out-group

When White perceivers viewed photos of two different Black men, their brain’s face area failed to distinguish between them. This effect occurred only with outgroup faces, while it accurately distinguished between two different White individuals.

Understanding Group Dynamics: The Outgroup Homogeneity Effect and Its Impact

Two or more people who interact with each other and have a similar goal, i.e. to constitute a group. There are several types of groups and subgroups existing in the society. The members of the group we identify ourselves with and perceive ourselves to be a part of based on some criteria (like race, similar religious backgrounds, academic group or other similar aspects) are the ingroup members, the rest are called the outgroup members and the group is referred to as outgroup. We tend to form an outgroup with respect to an ingroup. Research shows that people often fail to individuate social outgroup members, perceiving them only as part of that group. This phenomenon, called the outgroup homogeneity effect, occurs when people perceive members of a racial out-group as similar.

Psychologists at Harvard University have tried to explore this phenomenon using fMRI repetition suppression to investigate the neural representation underlying this effect. In a pre-registered study, 29 White human perceivers responded to pairs of faces indicating White or Black targets. For each of the pairs, the second face depicted either the same target as the first face, a different target from the same race, or a scrambled face outline. Researchers found that the fusiform face area only differentiated faces effectively when they were within the perceivers’ racial ingroup. However, the face-selective cortex did not discriminate between other-race individuals.

Discover how visual processing errors lead to outgroup homogeneity, impacting our ability to distinguish between social groups

Across two studies with 67 individuals, perceivers were slower to distinguish and less likely to remember different outgroup members.

These results show the outgroup homogeneity effect arises from early visual processing errors merging representations of outgroup members. The result highlighted the failure of basic representational mechanisms in processing individuals from other social groups differently from ingroups.