CHAMPAIGN, Ill. — In a study that tracked explicit and implicit bias against stigmatized groups in 33 countries between 2009 and 2019, researchers found substantial reductions in explicit, self-reported bias against all categories of stigma they examined: age, race, body weight, skin tone and sexual orientation. The picture for implicit bias, which is sometimes described as "hidden" or "automatically revealed" bias, was more varied, however.
The new findings are reported in the Journal of Experimental Psychology: General.
"We used data from Project Implicit , a website established in the early 2000s that serves both as a venue to educate people about implicit processes and as a site for collecting data," said University of Illinois Urbana-Champaign psychology professor Benedek Kurdi , who led the research with Tessa Charlesworth , a professor in the Kellogg School of Management at Northwestern University. The data was collected from 1.4 million participants from 33 countries mostly in the northern hemisphere but also from Argentina, Australia and Brazil.
Explicit bias is what people willingly share about their attitudes toward other groups or individuals, Kurdi said. Implicit bias is revealed through other means.
"This is usually a task where people are performing a behavior," he said. "For example, they may be asked to categorize images and words and, based on how quickly they can do that, we can make inferences about their attitudes."
For example, a person may quickly associate young, thin or light-skinned people with positive traits while more readily associating people who are older, heavier or who have darker complexions with more negative attributes, Kurdi said.
"If you take a test such as the Implicit Association Test , there is less opportunity for you to consciously control your response," he said.
When analyzing data from people based in the U.S., previous studies found obvious downward trends in self-reported bias against various stigmatized groups.
"Since 2007, respondents in the U.S. have been expressing less anti-old/pro-young, anti-fat/pro-thin, anti-gay/pro-straight, anti-dark skin/pro-light skin and anti-Black/pro-white attitudes," the authors of the new study wrote. "These findings align with similar, well-documented trends obtained in representative U.S. surveys … and likely reflect changing norms about the acceptability of expressing negativity toward stigmatized groups."
The U.S. data for some types of implicit bias also showed a downward trend.
"Specifically, implicit sexuality attitudes dropped in bias by 65% and are now close to neutrality. Implicit race and skin tone attitudes have also [showed declines in bias], although at slower but still notable rates of 26% and 25%, respectively," the researchers wrote.
Implicit bias related to body weight and age remained high in the U.S., however.
Kurdi and his colleagues wanted to compare the U.S. data to more global trends, to see if the same patterns prevailed. To do so, they broadened their study to include responses from 1.4 million individuals around the world. The data were collected from people in Argentina, Australia, Austria, Belgium, Brazil, Canada, China, Colombia, the Czech Republic, Denmark, France, Germany, Hungary, India, Ireland, Israel, Italy, Japan, Mexico, Norway, Poland, Portugal, Romania, Russia, Serbia, South Africa, South Korea, Spain, Sweden, Switzerland, Taiwan, Turkey and the United Kingdom.
When they analyzed the international responses, the researchers saw some surprisingly similar trends to those in the U.S., but with a few important differences.
"We looked at self-reported bias against age, body weight, sexuality, skin tone and race," Kurdi said. "And for every single one of them, people are reporting less bias, and they are reporting more egalitarian social group attitudes. But then when you look at implicit attitudes, there is a lot more variability."
Between 2009 and 2019, self-reported bias dropped across the board internationally. At the low end, bias against people with higher body weight dropped 18%, and the most dramatic decline was seen in bias related to sexuality, which dropped 43% over that period. Self-reported bias related to age, skin tone and race also declined.
International trends in implicit bias were more variable, however. Between 2009 and 2019, there was a 36% drop in implicit bias related to sexuality, while implicit bias related to age, race and body weight remained stable. Implicit bias related to skin tone declined but then went up again, ultimately increasing by about 20% overall.
Race-related bias and bias related to skin tone are distinct from one another in many parts of the world, where lingering cultural traditions such as the caste system or a history of bias against darker-skinned individuals of the same race often persist, Kurdi said.
"In the U.S., the Black-white racial divide is the main racial distinction," Kurdi said, whereas in other countries social stigma may be primarily associated with a lighter or darker skin tone.
The key revelation of the study is that both explicit and implicit bias are malleable, Kurdi said. These changing attitudes likely reflect how members of traditionally stigmatized groups are portrayed in popular media and the news.
The most dramatic reductions in bias — both in the U.S. and internationally — involved attitudes toward people who are gay, the researchers found.
"It's not just that the average is changing, but almost every single country in the dataset changed toward less bias in sexuality attitudes," Kurdi said. "This is likely the result of several factors, including social movements, people coming out, and the fact that representation of gay people has become both more frequent and more diverse in media."
"Even with the U.S. data, I was very surprised that even implicit attitudes can change so quickly and so fundamentally in such a short period of time," Kurdi said. "And the fact that that seems to be happening — not only in this country but on a more global scale — also was surprising to me."
Kurdi also is a professor in the Beckman Institute for Advanced Science and Technology at the U. of I.
