Prejudice, especially towards immigration and immigrants, is a complex psychological phenomenon. While we’re still a long way from understanding why some people harbor strong negative feelings towards dissimilar others, the results of a study published in Physiology & Behavior suggest that it may be at least partially rooted in sensory mechanisms — that is, the way we perceive the world through our senses.
Participants were 805 Amazon Mechanical Turk users who completed the Body Odor Disgust Sensitivity questionnaire, a 12-item scale measuring sensitivity to body odors based on various scenarios (e.g. noticing someone’s feet have a strong odor). In addition, subjects were asked a series of questions relating to a fictive Central African population hoping to immigrate to the United States. The questionnaire included items related to transmission of disease, criminality, and dissimilarity in terms of food, hygiene and sanitation.
The study’s theoretical framework is provided by the Behavioral Immune System theory, which suggests that generalized negative attitudes towards dissimilar groups may be part of a broader suite of behaviors that allows individuals to detect and avoid diseases. According to the theory, the detection of a perceived threat via sensory perception (e.g. seeing pustules, smelling rot) triggers cognitive and behavioral responses, including disgust. Over time, this system would have been incorporated into social norms and, according to the researchers, can manifest as prejudice towards others.
The findings of their study lend support to this hypothesis. A statistically significant correlation was found between body odor disgust and xenophobic attitudes towards the fictive, dissimilar group. Additionally, perceived dissimilarity partially mediated the relationship between body odor disgust and xenophobic attitudes. In other words, participants who felt more dissimilar from the fictive Central African group, based on diet, hygiene and sanitation, were more likely to assume that they would bring disease and criminality with them to America. Finally, this negative attitude towards the fictive group predicted actual opposition among participants to immigration.
“Our results strengthen the theoretical framework of the behavioral immune system which assumes that disease avoidance may underlie some forms of prejudice, suggesting also that reluctance to accept unfamiliar practices in basic aspects of life may at least partially explain this link,” the researchers wrote in their study.
The sample population was limited to American participants, and the study’s results, plus any related social norms, behaviors and prejudices, should be considered in light of this restriction. Additionally, socioeconomic factors, which are known to correlate with opposition to immigration, were not taken into consideration.
Studies like this help us better understand where prejudicial and xenophobic attitudes come from, and how cognitive and behavioral systems mediate their entry into social norms.
The study, “Body odor disgust sensitivity is associated with prejudice towards a fictive group of immigrants“, was authored by Zakrzewska Marta, Olofsson Jonas K, Lindholm Torun, Blomkvist Anna, and Liuzza Marco Tullio.