By Steffi Kim
In 1995, social psychologists Mahzarin Banaji and Anthony Greenwald coined the term “implicit bias” to describe how deeply ingrained associations and attitudes can unconsciously influence behavior. The concept that some level of bias colors how we perceive the world, beyond our scope of conscious awareness and reasoning, has since received mainstream attention. This finding is both deeply troubling and a testament to the efficiency of the human brain, which is wired to form automatic categorizations to better ensure survival. There is no singular, specific neural region responsible for prejudice. Rather, bias arises from interconnected networks across the brain that are involved in perception, categorization, emotion, reasoning, and more.
From the onset, the brain appears wired to perceive people from different social groups in different ways, challenging the notion that true “color-blindness” can exist. The fusiform face area (FFA), within the fusiform gyrus of the temporal and occipital lobes, plays a key role in facial recognition and categorization. In a pattern replicated across literature, Golby et al. (2001) found that the FFA tends to display greater activity when viewing faces from our own racial group compared to those from other groups. Underlying the phenomenon known as own-race bias, this translates into being able to differentiate same-race faces more adeptly. This may occur for several reasons: the brain has more experience recognizing same-race faces, and from an evolutionary perspective, quickly identifying members of one’s own group would have been paramount for survival in a less globalized world. Nevertheless, when faces from other racial groups do not register as distinctively, it can translate to less individuation and more generalized stereotyping.
Beyond differences in perception, among the first studies examining how the brain reacts to members of other groups was conducted by Phelps and colleagues in 2000. Phelps et al. assessed participants’ levels of conscious racism before exposing them to photographs of both white and Black faces, while measuring brain activity with functional magnetic resonance imaging (fMRI). They found that self-professed “unbiased” white participants exhibited stronger activation in the amygdala when viewing unfamiliar Black faces compared to unfamiliar white ones. This heightened activity was particularly concentrated in the left-superior amygdala, associated with recognizing fearful expressions, and correlated with scoring higher on the Implicit Associations Test (IAT) for implicit bias. The amygdala is involved with threat detection and the fight-or-flight response and, as part of the limbic system, is one of the evolutionarily older brain structures. Thus, when exposed to members of other racial groups, negative associations may trigger instinctive emotional responses in the amygdala, placing the brain in a state of heightened alarm before conscious processing occurs.
While the brain may flag people belonging to different groups in unwanted ways, the good news is that conscious reasoning can mitigate many of the effects of implicit bias. In a follow-up study, Cunningham et al. (2004) found that extending the exposure time to the Black faces from 30 ms to 525 ms resulted in relatively lower levels of amygdala activation, which were replaced by greater activation of the frontal cortex instead. Two areas with particular activity were the dorsolateral prefrontal cortex, which is implicated in working memory and logical reasoning, and the anterior cingulate cortex (ACC), which is uniquely positioned between the emotional limbic system and the frontal lobe. The ACC plays a key role in detecting conflict and correcting cognitive errors, or mismatches between the brain’s expectations and reality. It follows that implicit bias is most likely to arise in particular circumstances when people are rushed, distracted, or cognitively drained. When the brain has more time to process and react, higher-level cognitive functioning can override automatic stereotypical associations and mitigate unwanted bias.
Encouragingly, these neural patterns are malleable, even when the brain initially reacts to people from other groups in less-than-positive ways. By intentionally slowing down and checking stereotypes, we can reduce the influence of implicit bias and remain in control. Among the best ways to mitigate bias toward other groups, on both an explicit and implicit neuroscientific level, is through getting to individually know members from other groups and forming interpersonal bonds. Farmer et al. (2020) found that participants who had more positive intergroup contact with Black individuals showed increased fusiform gyrus activity in response to Black faces, indicating that the visual cortex can become more adept at perceiving members from other groups the more familiar with them we become. Similarly, Phelps et al. (2005) found that while exposure to unfamiliar Black faces triggered greater amygdala activity, associated with fear-based responses, viewing well-regarded and familiar Black faces like Michael Jordan did not trigger this heightened amygdala response. In other words, forming positive, individualized associations with members from other groups can counter harmful generalizations and lead to less biased, more fruitful interactions. Importantly, Kubota (2024) points out that, beyond individual awareness, meaningfully reducing implicit bias requires broader changes to the cultural and societal systems that reinforce these patterns.
References:
Cunningham, W. A., Johnson, M. K., Raye, C. L., Gatenby, J. C., Gore, J. C., & Banaji, M. R. (2004). Separable neural components in the processing of black and white faces. Psychological Science, 15(12), 806-813.
Farmer, H., Hewstone, M., Spiegler, O., Morse, H., Saifullah, A., Pan, X., … & Terbeck, S. (2020). Positive intergroup contact modulates fusiform gyrus activity to black and white faces. Scientific reports, 10(1), 2700.
Golby, A. J., Gabrieli, J. D., Chiao, J. Y., & Eberhardt, J. L. (2001). Differential responses in the fusiform region to same-race and other-race faces. Nature neuroscience, 4(8), 845-850.
Greenwald, A. G., & Banaji, M. R. (1995). Implicit social cognition: attitudes, self-esteem, and stereotypes. Psychological review, 102(1), 4.
Kubota, J. T. (2024). Uncovering implicit racial bias in the brain: the past, present & future. Daedalus, 153(1), 84-105.
Phelps, E. A., O’Connor, K. J., Cunningham, W. A., Funayama, E. S., Gatenby, J. C., Gore, J. C., & Banaji, M. R. (2000). Performance on indirect measures of race evaluation predicts amygdala activation. Journal of cognitive neuroscience, 12(5), 729-738.