Behavioral immune system
Encyclopedia
The behavioral immune system is a phrase coined by the psychological scientist Mark Schaller
to refer to a suite of psychological mechanisms that allow individual organisms to detect the potential presence of disease-causing parasites in their immediate environment, and to engage in behaviors that prevent contact with those objects and individuals.
These mechanisms include sensory processes through which cues connoting the presence of parasitic infections are perceived (e.g., the smell of a foul odor, the sight of pox
or pustules), as well as stimulus–response systems through which these sensory cues trigger a cascade of aversive affective, cognitive, and behavioral reactions (e.g., arousal of disgust
, automatic activation of cognitions that connote the threat of disease, behavioral avoidance).
The existence of a behavioral immune system has been documented across many animal species, including humans. It is theorized that the mechanisms that comprise the behavioral immune system evolved as a crude first line of defense against disease-causing pathogens.
In addition, the behavioral immune system appears to contribute to xenophobia
and ethnocentrism
. One implication is that these prejudices tend to be exaggerated under conditions in which people feel especially vulnerable to the potential transmission of infectious diseases.
Additional lines of research on the behavioral immune system have shown that people engage in more reticent and conservative forms of behavior under conditions in which they feel more vulnerable to disease transmission. For instance, when the potential threat of disease is made salient, people tend to be less extraverted or sociable. Evidence suggests that the behavioral immune system also incorporates mechanisms designed to search out and process (heuristic) signs of disease at the level of basic visual attention.
too. One study found that the mere visual perception of diseased-looking people stimulated white blood cells to respond more aggressively to infection (as indicated by the production of the proinflammatory cytokine
Interleukin 6
in response to a bacterial stimulus).
Mark Schaller
Mark Schaller is a psychological scientist who has made many contributions to the study of human psychology, particularly in areas of social cognition, stereotyping, evolutionary psychology, and cultural psychology. He is Professor of Psychology at the University of British Columbia.Schaller was...
to refer to a suite of psychological mechanisms that allow individual organisms to detect the potential presence of disease-causing parasites in their immediate environment, and to engage in behaviors that prevent contact with those objects and individuals.
These mechanisms include sensory processes through which cues connoting the presence of parasitic infections are perceived (e.g., the smell of a foul odor, the sight of pox
Pox
A pox is a type of disease, often caused by an animal virus, characterised by pockmarks. The term may be used to refer to disease.Pox, as a disease, may refer to:*Poxviruses...
or pustules), as well as stimulus–response systems through which these sensory cues trigger a cascade of aversive affective, cognitive, and behavioral reactions (e.g., arousal of disgust
Disgust
Disgust is a type of aversion that involves withdrawing from a person or object with strong expressions of revulsion whether real or pretended. It is one of the basic emotions and is typically associated with things that are regarded as unclean, inedible, infectious, gory or otherwise offensive...
, automatic activation of cognitions that connote the threat of disease, behavioral avoidance).
The existence of a behavioral immune system has been documented across many animal species, including humans. It is theorized that the mechanisms that comprise the behavioral immune system evolved as a crude first line of defense against disease-causing pathogens.
Implications for human behavior
Within the psychological sciences, there is extensive research linking the behavioral immune system to a variety of prejudices—including prejudices against people who aren't actually diseased but are simply characterized by some sort of visual characteristics that deviate from those of a subjectively prototypical human being. The disease–avoidant processes that characterize the behavioral immune system have been shown to contribute to prejudices against obese individuals, elderly individuals, and people with physical disfigurements or disabilities.In addition, the behavioral immune system appears to contribute to xenophobia
Xenophobia
Xenophobia is defined as "an unreasonable fear of foreigners or strangers or of that which is foreign or strange". It comes from the Greek words ξένος , meaning "stranger," "foreigner" and φόβος , meaning "fear."...
and ethnocentrism
Ethnocentrism
Ethnocentrism is the tendency to believe that one's ethnic or cultural group is centrally important, and that all other groups are measured in relation to one's own. The ethnocentric individual will judge other groups relative to his or her own particular ethnic group or culture, especially with...
. One implication is that these prejudices tend to be exaggerated under conditions in which people feel especially vulnerable to the potential transmission of infectious diseases.
Additional lines of research on the behavioral immune system have shown that people engage in more reticent and conservative forms of behavior under conditions in which they feel more vulnerable to disease transmission. For instance, when the potential threat of disease is made salient, people tend to be less extraverted or sociable. Evidence suggests that the behavioral immune system also incorporates mechanisms designed to search out and process (heuristic) signs of disease at the level of basic visual attention.
Implications for human culture
The behavioral immune system also has consequences at a cultural level of analysis. Under ecological circumstances in which diseases are more prevalent, people also tend to display more reticent and socially restricted forms of behavior, and human cultures are defined by more conservative norms and value systems.Implications for immunology
Some research suggests that the behavioral immune system has implications for the functioning of the "real" immune systemImmune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
too. One study found that the mere visual perception of diseased-looking people stimulated white blood cells to respond more aggressively to infection (as indicated by the production of the proinflammatory cytokine
Cytokine
Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...
Interleukin 6
Interleukin 6
Interleukin-6 is a protein that in humans is encoded by the IL6 gene.IL-6 is an interleukin that acts as both a pro-inflammatory and anti-inflammatory cytokine. It is secreted by T cells and macrophages to stimulate immune response, e.g. during infection and after trauma, especially burns or other...
in response to a bacterial stimulus).