The Biased Brain

June 16, 2020

Written by: Rebecca Somach


By now, you’ve heard the protests and you’ve seen the news. Across the globe people are standing up and speaking out about injustice. These injustices are not new, and this is not the only time people have spoken up, but this has been a different scale than previous outcries. The current movements are asking us to reevaluate the bias in our countries, institutions, communities, and in ourselves. The definition of ‘bias’ is “unreasonably hostile feelings or opinions about a social group; prejudice.”1 Treating others differently can apply to many aspects of a person, including their race, ethnicity, sexuality, gender, religion, age, nationality, and/or socioeconomic class. Prejudice and bias are culturally constructed to give power to some and keep it from others. As scientists, we also want to know if part of this bias is due to our brains.


Our brains are good at categorizing things. As social creatures, individuals who were able to identify humans and recognize them as part of the same tribe had a distinct evolutionary advantage. Our brains still have this tendency to categorize other humans. For instance, in one study, participants looked at pictures of faces while scientists used fMRI to identify activated brain regions. The scientists focused on the fusiform face area, a region of the brain thought to respond specifically to human faces. Although the fusiform face area was activated by all faces, it responded more strongly to faces of the same race as the participant.2 This result seemed to indicate that people would recognize others of the same race more easily. Taken a step further, another group of scientists found that the anterior cingulate cortex (ACC) responded to an image of another person being hurt.3 The scientists thought this response represented a sense of empathy. However, the ACC did not react as strongly to images of other races. The scientists found that this empathy mainly existed towards people of a similar race to the observer.


How we identify with people might depend on whether we consider them part of our group, or as ‘others.’ Research has shown that our brains can be influenced into trusting some people as part of our communities, and other people as separate. In one study, African American and Caucasian subjects were shown unfamiliar faces that were African American or Caucasian.4 They were asked to choose another face whose race matched the one they were shown while their brain activity was recorded with fMRI. The researchers saw that there was more activity in the amygdala when the participants saw African American faces. This was true for the participants who were African American themselves as well as the Caucasian participants. The amygdala is a region that processes fear. The scientists believed that the results were due to “culturally learned negative associations.”4 This study suggests that the way our culture represents and treats others may affect the ways our brain encounters new people, regardless of whether on the outside they might be part of the “same group.” These, and other experiments5 show that the brain not only creates groups, but is influenced by culture to decide who is in which group.

brick silhouettes

The quick reactions we can see in the brain may be one of the reasons behind implicit bias. Implicit bias is the psychological idea that everyone judges and evaluates people subconsciously. We do not realize that we are doing it, but it can contribute to our behaviors and how we interact with others.6,7 The studies described earlier2,3,4 often reveal implicit biases. Researchers avoid telling the participants what they are looking for so they can study natural reactions to their tests. The bias in those earlier studies wasn’t said out loud, but was nestled within the activity of the brain itself without the participants even realizing it.


One of the first steps we can all do to improve the way we approach one another is to recognize that we all have implicit bias and that we need to move forward from there. Getting people to admit that they, or their communities, might be prejudiced, even implicitly, can be a challenge in itself. People take sides, sometimes viewing anyone who isn’t on their “side” as an enemy. If it is the case that people want to live good and peaceful lives, why deny that they might be biased? Shouldn’t they accept what they need to fix in themselves and try to move forward as a community together? What fuels the pushback?


Challenging our intrinsic biases feels like a challenge to our thoughts. This is connected with an idea in psychology called “cognitive dissonance”: that if a person has two contradictory ideas about the world, it causes them extreme psychological discomfort.8 They will try to reconcile the ideas to make them match.


The theory of cognitive dissonance has existed since the 1960s, but scientists are now looking at this theory using neuroscience methods such as EEG and fMRI. In one test, scientists put participants in an fMRI machine, which is safe but somewhat cramped and noisy. The scientists told some participants that another person was lined up to do the test next, but that person was nervous about the scanner. The participants were told to answer questions about the scanner in a positive way so that the next person would not be scared. If the question was “I feel comfortable in the scanner,” they were supposed to answer that they were, even if they weren’t. This forced the participants to say things they might not actually believe, an example of cognitive dissonance.10 Scientists have identified several brain regions involved with dissonance, including the posterior medial frontal cortex (pMFC), ACC, insula, striatum, and dorsolateral prefrontal cortex.7 This type of research shows that cognitive dissonance isn’t just an idea, but can be detected and measured in the brain.

white black heads

Cognitive dissonance is harder to overcome when people must reckon with more serious topics than their comfort with a noisy MRI machine. Most people have the simple, but powerful belief: “I am a good person.” They follow laws, do their jobs, have families, and are part of communities. When they are faced with the ideas of “being biased against people is a bad thing” and “I am biased against certain people,” this brings about cognitive dissonance. The idea that they are biased does not fit with their normal worldview that they are a good person. This causes them psychological discomfort that they will find a way to fix.


One way people may attempt to silence their cognitive dissonance is by denying any acts or thoughts of bias, reasoning, “I am a good person, and therefore I can’t be biased.” Another is to say, “I am a good person and I show a bias. Therefore, biases are not bad because I am good and I’m biased”. In this way, they can keep their opinion the same, but blame the person who brought the bias to their attention. That is the easy way to solve cognitive dissonance, as it does not address the underlying biases. The harder way of fixing the dissonance is to say, “I am biased, and I know biases are bad. If I want to be the good person that I think I am, I need to fix my biases or the way I act.” This is a much harder process. This challenges the ways that the person is acting now, but it can lead individuals to true change.


The catch of cognitive dissonance is that it is not always in our direct control. Just like implicit bias, we aren’t aware that we change the way we think to fix cognitive dissonance. We don’t intentionally think, “I think that bias doesn’t exist.” Instead, it sneaks into our environment or comes from other people we love. “That person is smart and can’t be biased, so their opinions are valid”; “This person has always been kind to my family, so they can’t be prejudiced and I agree with their position”; “This institution has always taken care of me so their actions can’t be wrong.” It hurts us to feel that we’ve put our trust in someone or something that has failed us. It makes us feel scared to admit that what we’ve believed is wrong. What is important is to recognize that the ideas of, “that person is good” and, “that person might be biased” may coexist.


Psychologists looking into prejudice theorize that the way to reduce prejudice is to bring people together. This idea is called intergroup contact theory, which predicts that mingling of different types of people improves their relationships among the people they are mingling with as well as new people.11 It is by coming together that we can recognize that we may be wrong about our prejudices. It is also important to recognize that the only way for everyone to get better is to be unafraid of the possibility that we might be wrong, and to confront our implicit biases and cognitive dissonance head on. The only way to do that is to listen to people that have been hurt and recognize why we may be responsible. No one is immune to bias, we know that biologically and culturally. However, we can be responsible for what that means and recognize that we all have work to do, in our communities, and in ourselves.




We recognize that the way to improve situations is not just to write about it, but to take action ourselves. You can read how the Neuroscience Graduate Group at the University of Pennsylvania has responded to current biases in science and science education here.

If you want to read more about the current news and the way scientists and academics are addressing these issues, please find more at






Cover image via Pixabay user FelixMittermeier


Images 2 & 3 via Pixabay user geralt




  1. “Bias”
  2. Golby, A., Gabrieli, J., Chiao, J. et al. Differential responses in the fusiform region to same-race and other-race faces. Nat Neurosci 4, 845–850 (2001).
  3. Xu, X., Zuo, X., Wang, X., & Han, S. (2009). Do you feel my pain? Racial group membership modulates empathic neural responses. The Journal of neuroscience : the official journal of the Society for Neuroscience, 29(26), 8525–8529.
  4. Lieberman MD, Hariri A, Jarcho JM, Eisenberger NI, Bookheimer SY. An fMRI investigation of race-related amygdala activity in African-American and Caucasian-American individuals. Nat Neurosci. 2005;8(6):720‐722. doi:10.1038/nn1465
  5. Kubota, J. T., Banaji, M. R., & Phelps, E. A. (2012). The neuroscience of race. Nature neuroscience, 15(7), 940–948.
  6. Mason, Betsy. “Curbing Implicit Bias: What Works and What Doesn’t.” Discover Magazine, Discover Magazine, 5 June 2020,
  7. Greenwald, A., Lai, C. Implicit Social Cognition (2019) Annual Review of Psychology 71:419-445.
  8. Festinger, L. (1962). “Cognitive dissonance”. Scientific American. 207 (4): 93–107
  9. Izuma, K., & Murayama, K. (2019). Neural basis of cognitive dissonance. In E. Harmon-Jones (Ed.), Cognitive dissonance: Reexamining a pivotal theory in psychology (p. 227–245). American Psychological Association.
  10. van Veen, V., Krug, M., Schooler, J. et al. Neural activity predicts attitude change in cognitive dissonance. Nat Neurosci 12, 1469–1474 (2009).
  11. Pettigrew, T. F., & Tropp, L. R. (2006). A meta-analytic test of intergroup contact theory. Journal of Personality and Social Psychology, 90(5), 751–783.

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