Scientists use brain measurements to identify a video that significantly lowers racial bias

A recent study published in the journal PLOS One suggests that watching a specific, emotionally engaging video can reduce racial bias and increase generosity toward Black Americans. The findings provide evidence that media designed to capture the brain’s attention might offer a practical way to combat prejudice on a large scale.

Scientists Yilong Wang and Paul J. Zak wanted to find a widely accessible method to reduce out-group bias. Out-group bias refers to the human tendency to favor people who belong to one’s own social circle while avoiding or judging those perceived as outsiders. This tendency has evolutionary roots, as early humans favored their own groups to ensure survival, but in modern society, it limits social connections and harms communities.

Face-to-face interactions can reduce this prejudice, but these methods are expensive and hard to organize for millions of people. Wang and Zak aimed to test if a short video, selected using biological measurements, could alter attitudes and behaviors effectively over the internet. The scientists suggest that almost everyone has access to video content, making it an ideal medium for broad interventions.

“Racial tension continues to be high in the United States and other countries. To date, the most effective way to reduce out-group bias is direct contact with a person from an out-group, but that is not a scalable solution,” said study author Paul J. Zak, a professor at Claremont Graduate University and author of The Little Book of Happiness: A Scientific Approach to Living Better.

“My goal was to screen a library of videos to identify one with high neurologic value (a brain network my lab discovered and named ‘Immersion’ that we can measure every second with an app that applies algorithms to data from smartwatches) that would reduce negative attitudes and behaviors towards African-Americans.”

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The scientists conducted two separate experiments to test their ideas using a concept they call the brain as a predictor. This approach suggests that measuring the neurologic responses of a small group of people can accurately predict how a much larger population will react to the same stimulus.

In the first experiment, they recruited 62 participants to watch five short videos about the negative effects of racial bias. Instead of simply asking the participants which video they liked best, the researchers measured their neurologic Immersion.

The scientists measured this using optical sensors placed on the participants’ forearms. These sensors track variations in cardiac rhythms that reflect the activity of cranial nerves. This nerve activity indicates specific types of brain function associated with emotional resonance and sustained attention.

One video produced the highest peak immersion among the viewers. This video was an animated story about Dr. Ronald McNair, a Black astronaut who died in the 1986 Space Shuttle Challenger disaster. The video featured McNair’s brother narrating how the future physicist overcame severe childhood racism in South Carolina to eventually earn a doctorate from the Massachusetts Institute of Technology.

In the second experiment, the scientists tested this highly immersive video on a much larger scale. They recruited a representative sample of 1,097 adult residents of the United States. They randomly assigned participants to watch either the treatment video about Dr. McNair or a neutral control video showing natural scenes with relaxing music.

Before and after watching the videos, participants answered a survey measuring their positive and negative emotional states. They also completed a standard questionnaire designed to measure their positive and negative attitudes toward Black Americans. This allowed the researchers to establish a baseline of prejudice and see if the video shifted those perspectives.

To measure actual behavior rather than just opinions, the scientists had participants play a money-sharing exercise called the ultimatum game. This game requires participants to use theory of mind, which is the ability to understand and anticipate the intentions of others.

In this exercise, one person is given ten dollars and must propose how to split it with a second person. The second person can accept the split or reject it, in which case neither person gets any money. A fair split of five dollars is usually expected, while offering less is often viewed as unfair or stingy.

Participants were asked to make decisions as both the person offering the money and the person receiving it. They were paired with hypothetical partners given either statistically common white names, like Mike, or common Black names, like Demetrius. The researchers measured generosity by calculating the difference between what a participant offered and the minimum amount they were willing to accept themselves.

Baseline data from the control group revealed that bias against Black Americans exists across the general population but is concentrated in specific demographics. The scientists found that prejudiced attitudes were highest among men, younger adults aged 18 to 43, and people who identified as Republicans.

Watching the treatment video changed these patterns. The video reduced average self-reported negative attitudes toward Black Americans by eleven percent compared to the control group. The scientists found that the video increased positive emotions in the viewers, which helped drive this positive change in perspective.

The highly immersive video also changed how people shared their money in the economic game. Participants who watched the story of Dr. McNair showed a 104 percent increase in generosity when paired with a partner who had a common Black name. This effect was specific to out-group members, as the video did not change how much money people shared with partners who had common white names.

The behavioral changes were especially notable among certain demographic groups. For example, men in the treatment group showed an increase in monetary generosity of over 300 percent compared to men who watched the nature video. The video also successfully reduced self-reported biased attitudes among younger adults and Republicans, bringing their scores closer to the national average.

“The video had a very large impact on the behavioral task of sharing money,” Zak told PsyPost. “We hypothesized the video would have some effect, but to more than double the money shared with an African American stranger, especially both those reporting a high bias towards this group, shows the powerful impact of effective (i.e. high Immersion) communication.”

The scientists also wanted to know if these changes would last beyond the initial viewing. They followed up with a subset of the treatment group two weeks later to have them complete the surveys and the money-sharing game a second time. The follow-up data showed that the reduction in prejudiced attitudes and the increase in generosity persisted after this two-week waiting period.

“This surprised us,” Zak said. “That’s a really strong response from a single video and shows that human innate bias towards one’s own group can be reduced with just a bit of well-structured information about another group.”

The researchers note a few potential misinterpretations and limitations regarding their work. Because the study focused on a representative sample of adults in the United States, the findings might not apply to people living in other countries with different cultural histories. The research also specifically examined bias toward Black Americans, so it is not yet clear if the exact same methodology works for other marginalized groups.

“The data are based on a representative sample of U.S. adults so the findings generalize to the United States but may not hold for other countries,” Zak noted. “We also focused on bias towards Black Americans and our methodology, while likely to affect biases towards other groups, has not been shown to have an effect yet. In addition, there is no ‘brainwashing.’ People make their own choices, we are simply presenting information in an effective way that may or not not affect what they do.”

In the future, the scientists hope to explore how this approach might reduce other social problems. They plan to test if similar videos can decrease bias toward people of different sexual orientations, nationalities, genders, or religions. They also suggest testing the effects of virtual reality or augmented reality to see if more immersive technologies produce even stronger reductions in prejudice.

“We have been developing scalable neuroscience methodologies to influence attitudes and behaviors that cause social ills,” Zak said. “For example, we recently used this methodology to address the rising support in the United States for socialism — a state structure that has impoverished and killed millions of people. This publication showed that a video describing how voluntary exchange in markets has reduced poverty in the poorest places in the world increased support for economic freedom among Americans. We also launched the first Neuroscience as a Service (NaaS) company so that anyone can measure the neurologic value of communications and live experiences to improve these and is used worldwide.”

“While the results are important, I hope the methodology is used by others to reduce social ills. We showed that this is not difficult to do and that negative attitudes and behaviors are largely due to ignorance about others rather than people being ‘bad’ or ‘evil.’ Communication is vitally important to build a more harmonious world.”

The study, “A video intervention reduces racial bias in a representative sample of US adults: A brain as predictor study,” was authored by Yilong Wang and Paul J. Zak.