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Bias Against People Seen as Physically Dirty May Take Root as Early as Age 5

Bias against people seen as physically dirty can emerge in children as young as five years old and persist into adulthood, according to new research from Boston College and Franklin & Marshall College.

The findings, published in the Journal of Experimental Child Psychology, show these prejudices include those who are sick and may hold implications for people diagnosed with COVID-19.

In three experiments involving approximately 260 participants, the study found that children’s and adults’ biases were stronger when evaluating similarly-aged peers. The biases also crossed cultural boundaries when tested in the U.S. and India.

The findings carry social implications for the current COVID-19 crisis as well, as they suggest that people might adopt negative beliefs and attitudes toward those who contract the novel coronavirus, said Boston College Associate Professor of Psychology Angie Johnston, a co-author of the report “In sickness and in filth: Developing a disdain for dirty people.”

“With the exponential increase in the number of confirmed cases of COVID-19, people are increasingly likely to know somebody with the virus,” said Johnston.

“It will be critically important for both children and adults to know to stay away from individuals who are contagious. However, it is possible that the stigma directed toward those who test positive for the coronavirus will last well beyond the course of the illness, and that other, less warranted avoidance tendencies will form and persist.”

Avoiding filth and germs is typically advantageous. However, when other people are physically dirty or sick, often through no fault of their own — such as being homeless, or working a “dirty job” — the tendencies toward avoidance can lead to problematic social biases, said Joshua Rottman, an Assistant Professor at Franklin & Marshall and co-author on the report.

In the study, the researchers found that kids and adults from both the U.S. and India are less likely to trust information conveyed by people who are unclean, and they are also less likely to attribute positive traits — such as intelligence or kindness — to those they see as unclean or unhygienic.

The team used three experiments to rate bias in children (ages 5-9) and adults against individuals who were sick or physically unclean, and to determine whether these biases extended across cultures. Participants were shown photos of identical twins, one dressed neatly in a clean setting; the other in stained, disheveled clothing in a setting littered with trash.

The first experiment showed that children and adults considered clean adults to be more likely to possess favorable traits than dirty adults, and adults have particularly strong tendencies to trust information provided by clean adults.

The second experiment revealed that only children view clean children as possessing more favorable traits than dirty children, but both children and adults selectively trust the testimony of clean children.

A third experiment in India uncovered similar patterns of results.

“Taken as a whole, these findings suggest that people who are perceived to be dirty will be frequently mistrusted, marginalized, maligned, and misunderstood from an early age,” the researchers conclude.

“These biases are generally constant across different causes of dirtiness,” said Rottman. “There are not clear differences between biases directed toward individuals who are sick versus individuals who are intentionally dirty versus individuals who are accidentally dirty.”

In addition to the social implications for the current COVID-19 crisis, the study results may pertain to certain segments of society labeled as “dirty.” Currently, the researchers are looking at  whether dirtiness stereotypes — such as labeling immigrants as “dirty” — elicit similar social biases in children.

Source: Boston College

Bias Against People Seen as Physically Dirty May Take Root as Early as Age 5

Traci Pedersen

Traci Pedersen is a professional writer with over a decade of experience. Her work consists of writing for both print and online publishers in a variety of genres including science chapter books, college and career articles, and elementary school curriculum.

APA Reference
Pedersen, T. (2020). Bias Against People Seen as Physically Dirty May Take Root as Early as Age 5. Psych Central. Retrieved on December 4, 2020, from
Scientifically Reviewed
Last updated: 1 May 2020 (Originally: 1 May 2020)
Last reviewed: By a member of our scientific advisory board on 1 May 2020
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