People who reject the theory of human evolution tend to have more bigoted attitudes

Individuals who accept human evolution tend to exhibit reduced levels of prejudice compared to those who reject the scientific theory, according to new research published in the Journal of Personality and Social Psychology. The study indicates that disbelief in evolution predicts racism and prejudice around the world and in various cultural contexts.

“I have been interested in human-animal relations for a while now,” said study author Stylianos Syropoulos, a PhD candidate at the University of Massachusetts Amherst.

“I did my first study on the subject back as an undergraduate student, examining how and why people expand their moral circles to include/exclude animals or humans. Then in graduate school I joined the Psychology of Peace and Violence Program, where I became invested in research on understanding and preventing intergroup conflict and violence.”

“Further, I recently also came across a wonderful review article by Vezzali and colleagues which suggests that some interventions to reduce conflict can be non-conflict-specific,” Syropoulos said. “Namely, that means that they can focus on an unrelated psychological phenomenon outside the scope of the conflict, which in this case was belief in evolution.”

To examine the relationship between the acceptance of evolution and prejudicial attitudes, the researchers first analyzed very large sets of data collected by the General Social Survey and Pew Research Center.

For 10 years, the General Social Survey, a nationally representative survey of U.S. citizens, included measures of the belief that humans developed from earlier species of animals. An analysis of responses from 8,963 participants found that the belief that humans evolved from animals was associated with reduced prejudice, less racist attitudes and reduced support for discriminatory behaviors. This was true even after controlling for education level, religiosity, political beliefs, family income, and gender.

The researchers also analyzed Pew Research Center data from 21,827 Christian individuals in 19 Eastern European countries. Pew asked the participants whether “Humans and other living things have evolved over time” or “Humans and other living things have existed in their present form since the beginning of time.” After controlling for education, importance of religion, age, and gender, the researchers found that those who denied that humans had evolved tended to exhibit reduced acceptance of outgroups, such as Roma and Catholics.

Next, Syropoulos and his colleagues analyzed Pew Research Center data from 28,004 Muslim individuals in 25 countries in Africa, the Middle East, and Asia. They found that disbelief in evolution was associated with decreased acceptance of Christians and with the tendency to only have Muslim friends. Similarly, an analysis of responses from 3,562 participants in Israel found that disbelief in evolution was associated with support for preferential treatment for Jews, less support for peace between Israelis and Palestinians, and greater support for the expulsion of Arabs.

Syropoulos and his colleagues also conducted their own studies.

An online study of 499 U.S. residents recruited via Amazon’s Mechanical Turk crowdsourcing platform found that disbelief in evolution was associated with hostility towards Iran, Egypt, Qatar, Turkey and Panemistan (a fictitious country). In two additional studies, which included 509 U.S. residents recruited via Amazon Mechanical Turk and 1,072 students recruited from introductory psychology courses, the researchers found that belief in human evolution and perceived similarity of self to animals were only moderately correlated, suggesting that they are “psychometrically distinguishable constructs.”

“Our findings were consistent across cultural, religious, and national contexts, for majority and minority groups, and even towards groups that were fictional (i.e., created by the research team),” Syropoulos told PsyPost. “These findings are correlational, meaning we cannot make a causal argument about this relationship, but importantly, this relationship was consistent, and remained significant after adjusting for key psychological variables such as ideology or religiosity.”

“We believe this link makes sense because of theoretical work on Social Identity Theory (i.e., when people believe in evolution, they are more likely to believe that they are similar to other people, as we all have a common ancestor); Terror Management Theory (i.e., in short, people are less defensive of their cultural worldviews and more accepting of others) and Moral Expansiveness Theory (i.e., people who believe in evolution potentially expand their moral circle to include animals, as they perceive them and animals to originate from a common ancestor, which in turn leads to them valuing people from other groups a lot too).”

The researchers noted that Darwin’s theory of evolution has been cited to perpetrate racism and other forms of prejudice, in part through the phrase, “survival of the fittest,” used to describe the process of natural selection.

“There have been theoretical accounts that predict the opposite of what we found, so it was exciting for us to show that this actually is not the case, that the opposite is true and that belief in evolution seems to have pretty positive effects,” co-author Bernhard Leidner said in a news release.

Despite using nationally representative data from across the world, the correlational nature of the data prevented the researchers from making causal claims about the relationship between disbelief in evolution and prejudicial attitudes. To overcome this limitation, Syropoulos and his colleagues conducted a final study of 1,279 U.S. residents in which they attempted to experimentally manipulate belief in human evolution.

Participants were randomly assigned to read about how humans have evolved from animals, read about evolution of currency from coins to paper bills, or read nothing before completing assessments of prejudicial attitudes.

Reading about evolution did not directly reduce prejudice. But the manipulation did reduce prejudice indirectly through changes in participants’ self-reported beliefs in human evolution. “Thus, although the manipulation itself did not prove to be effective, there is evidence to suggest that for those people who were convinced by it, prejudice was reduced,” the researchers explained.

“It’s not easy to make everyone believe in evolution, as depending on one’s education and religious background, they might reject this theory altogether,” Syropoulos told PsyPost. “More research is required in that direction.”

“This project was the result of a cross-national collaboration including researchers from the United States (Dr. Bernhard Leidner from UMass Amherst; Dr. Jeff Greenberg and PhD Candidate Dylan Horner from University of Arizona) and Dr. Uri Lifshin from Reichman University in Israel (who is a joint first-author on the paper). Additional work on perceived similarity to animals is coming out soon from this collaboration which will further validate this claim,” Syropoulos added.

The study, “Bigotry and the human-animal divide: (Dis)belief in human evolution and bigoted attitudes across different cultures“, was authored by Stylianos Syropoulos, Uri Lifshin, Jeff Greenberg, Dylan E. Horner, and Bernhard Leidner.

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