crowd with pathogens in between people

Does pathogen avoidance lead to prejudice based solely on group membership?

by Anastasia Makhanova

The COVID-19 pandemic has profoundly affected people’s psychology and behavior. At the grocery store, for example, people might avoid busy aisles. If a stranger is coughing, people may preemptively step away and walk in another direction. People may altogether avoid grocery stores—and the store’s other patrons—and order grocery delivery to their door. Although the pandemic has kicked some of these behaviors into overdrive, the motivation to avoid pathogens is not new. Indeed, pathogens have been a recurrent and pernicious threat throughout the evolutionary past and that pressure shaped adaptive strategies that function to minimize pathogen threat.

Some strategies, as in the examples above, involve vigilance to environmental cues—including other people—that are associated with increased likelihood of contagion. People can detect signs of illness in faces, smells, and posture. Heightened pathogen avoidance motives, however, also lead to a more conservative threshold about whether a cue is linked to pathogen threat. That is, people who typically are more (vs. less) vigilant to pathogens and people who are in the moment reminded about the dangers of pathogens tend to avoid others who belong to groups only stereotypically associated with illness. Indeed, pathogen concern has been linked to age-based prejudice, weight-based prejudice, and—most consistently—people who belong to a different ethnic or racial group.

Why does heightened pathogen avoidance lead to greater prejudice against people from ethnic and racial outgroups? On the one hand, myriad historic accounts detail terrible consequences of pathogen transmission between two groups during initial contact, such as when the smallpox virus, brought over by the Spaniards, decimated the Aztec population. On the other hand, in the evolutionary past, contact with other racial and ethnic groups was likely so infrequent that there would have been insufficient pressure for the development of a specific adaptation to avoid outgroups in response to an illness outbreak. Nevertheless, it is plausible that—when pathogen avoidance is heightened—people would become especially wary of outgroups.

Although numerous studies show that heightened pathogen avoidance motives are linked to bias against people from racial and ethnic outgroups, it is unclear whether this pattern of results is specifically due to group membership (i.e., this person is an outgroup member and not an ingroup member) or another appraisal of the person. We conducted a study to identify the unique influence of group membership on social avoidance under the pressure of pathogen threat.

To isolate group membership, we relied on a method from social psychology called the Minimal Group Paradigm developed by Henri Tajfel and his colleagues in the early 1970s. This paradigm involves creating novel, arbitrary groups called minimal groups that are not connected people’s existing social identities. When people are placed into one of two minimal groups, they immediately develop a favorable attitude toward that group and a relatively unfavorable attitude about the outgroup. We hypothesized that, if heightened pathogen avoidance is associated with prejudice against racial and ethnic outgroups because of their outgroup status, then heightened pathogen avoidance would be associated with greater prejudice against a minimal outgroup.

First, to create minimal groups, we asked participants to complete a personality questionnaire. Without scoring their answers, we told participants that they were either “Green” or “Orange” personality type at random. Next, we used an experimental manipulation to heighten pathogen avoidance for some of our participants under the guise of being interested in how personality affected perceptions of photographs. Participants were randomly assigned to one of three groups: pathogen threat, non-pathogen threat, and control. Each watched a slideshow of images depicting people who were sick, anxiety-inducing scenes such as tornadoes, or furniture, respectively. Then, we asked participants to tell us about their initial intuitions about whether they would like other people who were part of their minimal ingroup (i.e., Orange if the participant was assigned to Orange) and other people who were part of their minimal outgroup (i.e., Green if the participant was assigned to Orange). Given the classic findings that people tend to like their ingroup and dislike their outgroup, we hypothesized that people in the pathogen threat condition (relative to those in the other two conditions) would show a greater divide: they would rate the minimal ingroup even more positively and the minimal outgroup even more negatively.

Unfortunately, we did not find support for our hypothesis. There were no differences between the three conditions in terms of the relative preference for the minimal ingroup versus the minimal outgroup. We did, however, replicate the classic findings: everyone evaluated the minimal ingroup more positively than the minimal outgroup.

We conducted exploratory analyses to examine whether people who were predisposed to heightened pathogen avoidance (i.e., people who reported higher trait levels of pathogen disgust) reacted differently to the experimental manipulation than those who were low in pathogen avoidance. Although the pattern of results in those analyses was largely inconclusive, we did find that people predisposed to heightened pathogen avoidance reacted more strongly to the Minimal Group Paradigm as a whole. That is, the difference between the ingroup and outgroup evaluations was greater for people high in pathogen disgust compared to those low in pathogen disgust. This latter finding, although exploratory, does suggest that some aspects of people’s pathogen avoidance psychology may be specifically attuned to information about group boundaries.

Generally, our findings show that, when people are faced with a situation that increases their concern about pathogen threat, they are unlikely to be reacting only to whether someone is an ingroup or outgroup member. In such situations, other appraisals are likely driving the observed biases against racial and ethnic outgroups.