Prejudice is an unfortunately common part of human interaction. People judge and stereotype all the time, even when they don’t consciously intend to. These ways of thinking emerge naturally as part of the way human brains work, and the way we tend to conform as a species. A new study by scientists led from the Korolinska Institutet has just given us a little more insight to the way our brains create prejudice, which may in the future help us learn to eliminate it.

Why Do We Form Prejudices?

Prejudice is typically defined as a preconceived judgment or opinion on something or someone that has no basis in fact or reason. That is, people who are prejudiced against someone often make judgments without paying attention to case-by-case facts, but rather by relying on a stored opinion about the group that person belongs to. Prejudices often lead to stereotyping and discrimination, and can be against all sorts of social groups, including gender, ethnic background, or social status.

It seems our tendency as humans to become prejudiced stems from the evolutionary advantage of categorization. Mentally grouping things helps us make sense of the world around us, which often bombards our brains with an unmanageable amount of information. To sift through all of this input, the brain tries to create categories with general descriptions that it can rapidly sort information into. This categorization does not only apply to those things and people around us, but also to ourselves, and we have a tendency to gravitate toward those we deem to be like us.

Prejudice occurs when generalized labels of “good” or “bad” are applied to entire groups. When people decide on their “in-group,” or the group they feel they belong to, all other groups are by default “out-groups.” There is an innate bias toward one’s own group, not only to perceive it as better than the “out-group,” but to be more accepting of individual flaws of individuals within the in-group, something that becomes very relevant in the study discussed later.

In evolutionary terms, it was beneficial to develop a bias toward the out-group because they were viewed as competition when resources were limited. Out-groups can also be viewed as a threat to one’s own culture, language, and attitudes.

Prejudice In The Brain

At its most basic level, prejudice is an association of a stimulus to a behavioral response. Though sometimes our reactions are helpful to survival (ie: Hear a bear coming toward us, brain tells you to be frightened), the human brain can also sound false alarms over stimuli that aren’t really a threat. It’s far safer to be overly cautious, but prejudice is a prime example of how a human’s tendency to incorrectly deem something dangerous can result in modern day problems.

Various studies have attempted to examine the neural processes involved in prejudiced thinking. The amygdala, a brain structure strongly associated with fear conditioning in the brain, has been a focus of researching where and how we form unconscious prejudice. In one 2007 study, white males were shown unfamiliar faces that varied in skin tone from very light to very dark. Greater amygdala activity was observed in the participants when viewing black faces as opposed to white, regardless of how dark the black faces were.

These unconscious prejudices do not only apply to racial prejudices, but to gender, sexuality, ethnic, and social biases as well.

How Fear Conditioning Fits In

Another way prejudice can arise is by conditioned learning. If a person has a bad or dangerous experience with someone they categorize as belonging to the “out-group,” they are likely to associate the entire out-group with that negative experience. Why, though, do we not become prejudice towards those in our own group? Surely we have all had a bad experience with someone in our in-group at some point in our lives, but we have not grown prejudiced toward the group as a whole.

The reason for that may be more clear thanks to the Karolinska Institutet study. Researchers found differences in brain activity after an aversive experience depending on if the experience was with a member of the person’s own group, or an out-group.

In the study, 20 white subjects were shown images of both black and white faces. One face in each racial group was paired with a small electric shock to the participant — an aversive stimulus. They were shown the round of images once more to show that they were actually safe, and the next day they participated in a social interactive task designed to measure brain activity and behavior when dealing with the different images.

Results showed that participants had exaggerated memories of the aversive stimulus associated with the out-group face. The amygdala played a key role in this, and predicted later expressions of discriminatory behavior toward new out-group members during the interactive task.

“A number of neuroimaging studies have investigated the neural components of acquisition and extinction of fears, and many others have examined the passive perception of in-group and out-group faces,” researchers wrote. “Our results go beyond these observations by showing that basic learning processes differ depending on whom we are learning to fear or dislike, and that these differences can predict an out-group bias during subsequent memory recall and interactive behavior.”

What Can We Do?

Empathy has been cited as the key factor in deconstructing ingrained prejudices. The most effective method for reducing prejudice so far is called the “contact hypothesis.” It suggests that when people actually have contact with members of an out-group, they are more likely to develop positive opinions about them. The contact must be meaningful and valuable to both parties in order to effectively reduce prejudice. Most importantly, being aware of one’s own prejudices is the first step taken in reducing them.

Source: Molapour T, Golkar A, Navarrete C, Haaker J, Olsson A. Neural correlates of biased social fear learning and interaction in an intergroup context. Neuroimage. 2015.

Ronquillo J, Denson T, Lickel B, Lu Z, Nandy A, Maddox K. The effects of skin tone on race-related amygdala activity: an fMRI investigation. Social Cognitive and Affective Neuroscience. 2007.