“Implicit bias” exists when we unconsciously hold attitudes towards others or associate stereotypes with them. (See our video: Implicit Bias) This is a controversial topic, but the evidence for the existence of implicit bias, both in the lab and in real life, keeps stacking up. There is substantial support for many forms of implicit bias, including gender discrimination and weight discrimination. What about racial discrimination?

On April 13, 2023, Ralph Yarl walked to a house he was unfamiliar with in order to pick up his twin younger brothers pursuant to his mother’s request. Unfortunately, he mistook the address and went to 1100 NE 115th Street in Kansas City rather than 1100 NE 115th Terrace. Yarl rang the doorbell, apparently waking the homeowner, an 84-year-old white male named Andrew Lester. Lester, it appears, opened the inner door and immediately fired a shot through the glass of the outer door, striking Yarl in the head. Yarl went down.  Lester opened the outer door and shot Yarl a second time, in the arm.

You will not be surprised to learn that Yarl, who miraculously survived the attack, was black. Why did Lester shoot Yarl without saying a single word? He said he thought Yarl was trying to break in, even though Yarl had rung the doorbell. Lester also told the police that he was afraid for his life because Yarl was a six-foot black man. In actuality, Yarl was a 16-year-old boy who was 5’ 8” tall and weighed around 140 pounds. He was hardly imposing physically.

This incident provides anecdotal support for mounds of evidence that because of implicit bias people of all races tend to treat young black men (as well as older black men) as more dangerous than comparable men who are white.

There is a substantial disparity between Yarl’s actual 5’8” frame and the 6’0” estimate from Lester. However, this misperception will not surprise psychologists. One study found that when shown pictures of black men and white men of the same size, subjects consistently judged the black men to be taller, heavier, stronger, and more capable of doing harm than the white men. Subjects also concluded that use of force by police against these black men was more justified than if the men of equal size were white.

There are several other studies in this vein.

  • When shown a video in which one person shoved another under ambiguous circumstances, if a black person was shoving a white person, 75% of subjects judged the action as “violent,” and only 6% concluded that the black person was just “playing around.” However, in an identical video where a white person shoved a black person, only 17% judged the action as “violent” and 42% concluded that the white person was just “playing around.”
  • One study found that when asked to read a story about a boy who behaved in antisocial ways, subjects told that the boy was black (versus those told that he was white) overestimated his age by more than four years, and perceived him as more culpable for his actions. Thus, teenage black males may be perceived not only as larger than they actually are, but older as well.
  • Shown a school record of a student who had misbehaved, teachers were more likely to label the student as a “troublemaker” and more likely to see a second infraction as part of a larger pattern of bad behavior if told that the student was black, as compared to teachers shown the identical record and told the student was white.
  • When prompted to think about crime, subjects in another study who viewed a page with many faces were more likely to have their attention drawn to black faces than to white faces.
  • In another study, when subliminally shown images of black faces, subjects were faster to visually detect a gun from a low-resolution image than if they were shown white faces. People tend to automatically associate black males with guns.
  • A psychologist tested subjects` for implicit racial bias and then had them read a story about a man who, as he went about his day, refused to pay his rent until his landlord agreed to repaint the apartment, and then bought something but later asked the merchant for his money back. Subjects were then primed to think of this man as black via subliminal cuts edited into a video. Almost all subjects judged the man as “hostile,” even those who had not tested high for racial bias.
  • When white people perceive that they are threatened by a person of color, they will describe that person as darker than if they did not feel threatened. And, they are more likely to describe a mixed-race face as “black” if they feel threatened.

The results of these laboratory studies are often reflected in real life:

  • One study in Texas examined millions of school disciplinary records, finding that black students were more than twice as likely to be suspended the first time they violated the rules as compared to white students. [find source]
  • A study of New York City’s controversial “stop, question & frisk” policy found that of 1.3 million stops over a two-year period, one-half were based on the vaguest possible reason under the policy—that the detainee had made “furtive movements.” Although only 23% of the city’s population is black, 54% of those stopped by the police were black. And, black citizens were much more likely to be frisked and subjected to physical force, but less likely to have a gun than white detainees (less than 1% of the black people frisked had guns).
  • A study of Oakland, California police stops of black drivers as compared to similar stops of white drivers found that the police officers were less respectful, less polite, less friendly, less formal, and less impartial. This “respect deficit” started within five second of the stop, indicating that it probably was not prompted by the black drivers’ conduct.
  • In a national study, researchers found a strong correlation between the level of implicit racial bias in an area’s white population and the disproportionate use of lethal force by police against blacks in that area.
  • In an analysis of nearly a thousand fatal shootings by police officers, it was determined that black victims are nearly twice as likely to be unarmed when shot than white victims. And, black suspects totally compliant with police orders are 21.3% more likely to be subjected to force than white suspects.
  • In a computer simulation, subjects were both faster to shoot at a black suspect holding a gun than a white suspect holding a gun, and more likely to mistakenly shoot an unarmed black subject than an unarmed white subject. However, studies of real police officers in the real world found that while they, too, were faster to shoot a black suspect with a gun than a white suspect, they were, probably due to their training, no more likely to shoot an unarmed black suspect than an unarmed white suspect.

Although at least some of shooter Andrew Lester’s relatives have indicated that he is explicitly racist as well as implicitly prejudiced, most of us are explicitly unbiased, but may still bear signs of implicit bias in our actions and decisions.

During much of evolution, small groups of humans competed with each other for resources. In order to survive, humans had to favor in-group members at the expense of out-group members. Often, that competition was deadly serious. As Yale’s John Bargh has written:

And so it went, down through the millions of years of our species.  We attacked and killed ‘them’ and they attacked and killed ‘us,’ at horrific rates by modern standards.  Distinguishing us from them, distrusting ‘them,’ and helping the others in our group became things we were born to do.  Today, underneath the nuances of faces, and the sharing of birthdays and name letters, the primordial code still is, Us versus Them, friend or foe, with us or against us.  There are domains in modern life where these powerful motors of action, which governed the lives of our hominid ancestors, still move us.  North versus South.  Germany versus France.  White versus Black.

Even in today’s roughly civilized society, we divide ourselves into groups, often unconsciously, using well-evolved instincts. According to NYU’s Dolly Chugh:

…automatic, mental shortcuts [are] needed for the human mind to process the eleven million bits of information received every moment.  Of those, we only consciously process forty bits of information, meaning that 99.999996 percent of our mental processing takes place on an unconscious level.  Some of that unconscious processing includes implicit biases.

The bottom line is that we come by our implicit bias naturally. Being infected with such biases does not automatically make bad people, even though we might do unfairly discriminatory things. But if we refuse to recognize the existence of implicit bias and do not attempt to minimize its effects on our actions and judgments, well, that’s another matter altogether. As Professor John Doris and colleagues note: “It would be comforting to conclude, when we don’t consciously entertain impure intentions, that all of our intentions are pure. Unfortunately, we can’t conclude that: many of us are more biased than we realize. And that is an important cause of injustice—whether you know it or not.”



John Bargh, Before You Know It. The Unconscious Reasons We Do What We Do (2017).

David Berreby, Us and Them: Understanding Your Tribal Mind ((2005).

Dolly Chugh, The Person You Mean to Be: How Good People Fight Bias (2018).

Keith Payne, Laura Niemi & John Doris, “How to Think about ‘Implicit Bias,’ Scientific American, March 17, 2018.

Birt Duncan et al., “Differential Social Perception and Attribution of Intergroup Violence: Testing the Lower Limits of Stereotyping of Blacks,” Journal of Personality and Social Psychology 34(4): 590-598 (1976).

Jennifer Eberhardt, Biased: Uncovering the Hidden Prejudice That Shapes What We See, Think, and Do (2019).

Jennifer Eberhardt et al., “Seeing Black: Race, Crime, and Visual Processing,” Journal of Personality and Social Psychology 87(6): 876-893 (2004).

Bertram Gawronski, “Six Lessons for a Cogent Science of Implicit Bias and Its Criticism,” Perspectives on Psychological Science 14(4): 574-595 (2019).

Phillip Goff et al., “The Essence of Innocence: Consequences of Dehumanizing Black Children,” Interpersonal Relations and Group Processes 106(4): 526-545 (2014).

Rachel Hatzipanagos & Timothy Bella, “A White Man Was ‘Scared to Death’ of Ralph Yarl. For Black Boys, This Isn’t New,” Washington Post, April 19, 2023.

Eric Hehman et al., “Disproportionate Use of Lethal Force in Policing is Associated with Regional Racial Biases of Resident,” Social Psychology and Personality Science 9(4): 393-401 (2018).

Jessica Nordell, The End of Bias: A Beginning. The Science and Practice of Overcoming Unconscious Bias (2021).

Howard J. Ross, Everyday Bias: Identifying and Navigating Unconscious Judgments in Our Daily Lives (2014).

Norman Salahieh et al., “Recovery of Black Teen Allegedly Shot by White Homeowner after Ringing Wrong Doorbell Is a Miracle, Attorney Says,” CNN, Apr. 19, 2023, at https://www.cnn.com/2023/04/19/us/kansas-city-ralph-yarl-shooting-wednesday/index.html.

John Paul Wilson et al., “Racial Bias in Judgments of Physical Size and Formidability: From Size to Threat,” Journal of Personality and Social Psychology 113(1): 59-80 (2017).

Xizhou Xie et al., “Learning in the Absence of Evidence: Untested Assumptions Perpetuate Stereotyping” poster presented at the Society for Personality and Social Psychology

Conference, New Orleans, 2020.

Holly Yan, “Grandson of White Homeowner Who Shot a Black Teen Who Rang His Doorbell Said He ‘Wasn’t shocked’ by the News. His brother Has a Different Take,” CNN, Apr. 21, 2023, at https://www.cnn.com/2023/04/20/us/ralph-yarl-shooting-andrew-lester-grandson/index.html .


Related Videos:

Implicit Bias:  https://ethicsunwrapped.utexas.edu/video/implicit-bias.

In-group/Out-group: https://ethicsunwrapped.utexas.edu/glossary/in-group-out-group.