Behavioral immune system

Last updated

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 infectious parasites or pathogens in their immediate environment, and to engage in behaviors that prevent contact with those objects and individuals. [1] [2] [3]

Contents

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. [2]

In humans and animals, activating a physiological immune response to pathogens is effective, but metabolically costly. Immune responses are activated at the expense of other fitness enhancing activities. [4] [5] Inflammation after infection can also be harmful to the body (e.g., contribute to diseases of aging). [6] [7] In addition to cultural adaptations to avoid pathogens, the behavioral immune system acts as a set of defense mechanisms to protect against pathogens before infection occurs [8] [9] [10]

Shows pathogens and non-infection diseases that create similar cues connoting presence of pathogens, real or perceived, which activate the behavioral immune system Quick simple diagram of the behavioral immune system.png
Shows pathogens and non-infection diseases that create similar cues connoting presence of pathogens, real or perceived, which activate the behavioral immune system

Proximate mechanisms

Mechanisms for the behavioral immune system 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). [2] [11]

Sensory components

Early and current research on behavioral immune system activation has been focused on visual cues or triggers that elicit responses. However, recent work suggests that other sensory modalities may be at work for disease detection. [12]

Smell

Studies show that olfactory cues of disease elicit disgust and predict pathogen avoidance behaviors. [12] In humans, body odors from diseased individuals are rated less desirable and likeable, [13] and perceived as unhealthier, more intense, and less pleasant. [14] Disgust of body odors is also influenced by the closeness of the source of odor. Odors from family members are rated as less disgusting than body odors from strangers. [15] Experimental studies showed that the presence of aversive odors leads to more prophylactic behaviors, such as more willing condom use [16] and less-direct prophylactic behaviors, like stricter punishment for moral violations. [17]

A new body of work has linked olfactory acuity to disgust and behavioral immune system responses. Given that olfactory cues for pathogen threat are often ambiguous and overgeneralized, a better ability to detect smells would lead to better pathogen avoidance. [12] Recent work suggests that higher olfactory acuity may be associated with higher avoidance motivation. [18]

Taste

Gustatory stimuli, particularly of spoiled foods, elicit feels of disgust and motivate pathogen avoidance behavior. [19] People with more disgust sensitivity are predicted to have more aversion to novel or foreign foods. [20]

Sight and touch

Visual cues of pathogen threat have been linked to increases in tactile sensitivity and lead to perceived people with accents as more foreign, especially among individuals with higher disgust sensitivity. [21] [22] Disgust sensitivity among individuals is also predictive of preferred amount of personal space. [23]

Overgeneralization

The “smoke detector principle [24] [25] of evolved systems that regulate protective responses has also been used to describe the behavioral immune systems tendency to overgeneralize. [26] Evolved responses to signals of pathogen threat cannot be perfect and rely on liberal identification criteria. [26] This makes the behavioral immune system susceptible to activating when pathogens are absent. Noninfectious physical and mental abnormalities including elderly appearance, [27] [28] disabilities, [29] obesity, [30] and disfigurement [31] [32] can act as cues of pathogen presence, when none are present. Even though many false alarms may be triggered in response to these nonharmful cues, the costs associated with behavioral immune activation may be relatively small to the costs of missing a true disease threat. [26]

Respond "Absent"Respond "Present"
Stimulus Present Miss Hit
Stimulus AbsentCorrect Rejection False Alarm
Table taken from signal detection theory (SDT). Cues, such as foul smell, that activate the behavioral immune system, such as the emotion of disgust, can have stimulus present (real pathogen threat) or absent (perceived pathogen threat).

Responses

Disgust

The pathogen disgust system and the behavioral immune system have been studied separately, but there is recognition that they are functionally the same. [33] Darwin first recognized that the emotion of disgust aided in avoiding "tainted" food. [34] The emotion of disgust has now been recognized as an adaptive function for avoiding pathogen exposure in response to cues of potential pathogen threat. However, disgust to pathogen-related cues should be context-dependent to function adaptively. [35] In one study on the Shuar, an indigenous subsistence-based population with high-pathogen stress, pathogen disgust sensitivity (PDS), measured with a disgust questionnaire, was used to predict pathogen infection. The study found that individual PDS was negatively correlated with pathogen infection predictive of the hypothesis that disgust acts as a pathogen defense mechanism sensitive to local costs and benefits of avoidance and infection. [35]

Functional flexibility

Functional flexibility is a term used to describe the ability of the behavioral immune system to adjust responses to pathogens depending on the individual’s infection-related threat and infection-relating vulnerability. Like many evolved threat management systems, the behavioral immune system is sensitive to the costs and benefits of pathogen avoidance. [36] [9] [37]

Reactive and proactive

Two categories of outputs can be generated by the behavioral immune system; reactive and proactive responses [26] Reactive responses occur in response to the presence of cues connoting an immediate infection risk. The responses generally take the form of avoidant or prophylactic behaviors. [38] [39] These can include restricted sexual attitudes, [40] [41] [42] positivity towards condom use, [43] and avoidance of people with cues associated with illness. [29] [44]

Proactive responses occur in response to the long-term and persistent threat of pathogens. [26] Across species, proactive management of pathogen threat can be seen in hygiene behaviors to mitigate reoccurring bacterial and viral threats. [45] Additionally, proactive responses can be seen in the importance placed on a potential mate's physical attractiveness, symmetry, and secondary sex-characteristics which are all indicators of health, and healthy people are less likely to carry disease. [46] [47] [48] [49] [50]

Influences on social psychology

Two social consequences of activating the behavioral immune system according to Ackerman et al., are "1. increased aversion and avoidance of unfamiliar and outgroup targets and 2. strengthened cohesion with familiar and ingroup targets." [26]

Interpersonal perception

Interpersonal perception is influenced by the behavioral immune system due to the early stage cognitive processes recruited for identifying pathogenic threat and the risks associated with interpersonal contagion.

Visual attention is one these early cognitive process recruited toward cues of pathogen threat and perceivers find it more difficult to visually disengage from faces possessing these cues, like physical abnormalities, even if no threat is present . [31]

The behavioral immune system may also cause people who perceive greater pathogen threat to report greater distinctions between ingroup and outgroup members, and classify strangers as more threatening. [51] [28] [21]

Judgment and decision-making

Judgments, inferences, and decisions about people and objects are other cognitive processes recruited by the behavioral immune system that are affected by pathogen threat. These processes motivative choices that help perceivers avoid unfamiliar stimuli that may include contamination dangers. [52] [53]

Examples of the influence perceived pathogen threat has on these processes include: avoidance of controllable risk, [54] reduced desire for social affiliation, [55] and devaluation of consumer products previously handled by strangers. [56]

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. [57]

Close relationships

The behavioral immune system influences potential mating choices and sexual behavior. High concern for chronic pathogen threats and environments with greater pathogen stress increase the value an individual places on physical attractiveness, [46] [49] [58] and lessens preference for mates with physical abnormality or sex-divergent features. [59] [60] Among perceivers, cues of pathogen prevalence (real or perceived) [26] are associated with more restricted sexual pursuits and attitudes to avoid infection. [40] [42] Opposite, more sexual opportunism is found in individuals with perceived insufficient immune systems for survival in environments with higher pathogen stress. [47]

Stereotyping and prejudice

Xenophobia is defined by Oxford languages as: dislike of or prejudice against people from other countries. Some studies indicate behavioral immune activation may lead to greater in-group preference and prejudice towards out-groups.

Another outcome of behavioral immune system activity is prejudice and stereotyping of outgroup members. Individuals at higher risk of pathogen infection are more likely to stigmatize other individuals possessing cues of disease, real or perceived. [44] [61] [62] [63] [64] [28] [65]

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. [66] [67] [27] In addition, the behavioral immune system appears to contribute to xenophobia and ethnocentrism. [64] [68] This can be seen among pregnant women, which face higher infection-related vulnerability, that express an increase ethnocentric views. [68] These attitudes might function as a way to avoid people with new pathogens or practices that local practices are unsuited to manage. [26] 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.

Group processes and cultural norms

The behavioral immune system has the ability to impact group intragroup attitudes and behaviors. Research shows that pathogen stress is associated with higher social conformity [69] [70] and higher levels of disgust, which aids in pathogen avoidance [56] [11] [71] [39] and predictive of greater sensitivity to moral violations. [26]

Some studies have used the behavioral immune system to explain the root of more fundamental dimensions of culture including the variance in: individualism/collectivism, [72] social and political orientation, [73] [74] [58] and religious beliefs, [75] [76] in response to levels of pathogen stress.

Collectivist cultures defined by behavioral manifestations such as ethnocentrism and social conformity which aid in pathogen avoidance, have been correlated with higher historical pathogen stress compared to individualistic cultures. [72] Given that there might be benefits associated with individualistic cultures in the societies they create, individualist cultures also confer greater pathogen exposure. In environments with greater pathogen stress, the behavioral manifestations of collectivism that help avoid pathogens may serve an adaptive advantage. [72]

Critiques of in-group preference

In-group preferences defined by the degree to which people prefer interacting with and investing in family, friends, and in group members has been suggested to be a function of the behavioral immune system in order to defend against pathogens. [72] [10] [76] However, these studies on cross-population level data have been criticized for not incorporating non-independence variables and alternative hypotheses. [77] [78] [79] In a follow up study, using measures the same measure for in-group preference, Hofstede's collectivism, Van de Vliert's in-group favoritism, and Fincher and Thornhill's strength of family ties, find that less government effectiveness is a better predictor of in-group preference than pathogen stress. [80]

Implications for immunology

Complimentary

Some research suggests that the behavioral immune system has implications for the functioning of the physiological immune system (PIS) 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). [81]

In other studies, exposure to visual environmental pathogen cues, in addition to increased feelings of disgust and prejudice responses associated with the behavioral immune system (BIS), upregulate oral and blood immune inflammatory biomarkers. [82] [83] [84] This body of literature suggests that visual cues connected to the BIS may invoke PIS responses when pathogen threat is immediate. [12]

Compensatory

In the absence of an immediate pathogen threat, the PIS and BIS may not be complimentary, but compensatory. For example, in an experiment that stimulated release of proinflammatory cytokines (IL-6, IL-1b, TNF-alpha) collected from healthy individuals, were not related to self-reported germ aversion, but in-vivo IL-6 levels were negatively correlated to germ aversion and perceived longevity. This research may highlight the function of the BIS for long-term health by decreasing proinflammatory responses (function of IL-6), linked to diseases of aging. [85]

Research also indicates that immune-relevant interventions which target pathogen transmission can interrupt behavioral responses. For example, receiving a flu vaccination or washing one's hands can reduce the extent of negative interpersonal and intergroup attitudes elicited by disease cues and concerns. [86]

Sickness behavior

The large body of literature on the behavioral immune system is focused on behaviors triggered by pathogen cues in the environment and the role disgust plays in mitigating exposure before infection. However, the emotion associated with being sick, lassitude, that is triggered by an active infection may also act as behavioral defense mechanism against pathogens. One study suggests that lassitude may help fight against an active infection by:

COVID-19

The behavioral immune system's prediction of ingroup favoritism and ethnocentric beliefs has been applied to individual beliefs during the global pandemic, COVID-19. In several studies, individuals who scored higher in dispositional worry about disease reported stronger preference for restrictive travel bans on several regions of Asia. Experimental increase of pandemic salience also increased support of travel bans on high risk nation (China and Italy), but not on low risk nations like Canada and Mexico. [88]

Another study measuring individual perceived vulnerability to disease (PVD) and responses to COVID-19 found that higher PVD was positively associated with stronger reactions to the threat of COVID-19, including increased anxiety, perceptions that people should alter their typical behavior, and self-reported importance of social distancing. [89]

Related Research Articles

<span class="mw-page-title-main">Fear</span> Basic emotion induced by a perceived threat

Fear is an intensely unpleasant emotion in response to perceiving or recognizing a danger or threat. Fear causes psychological changes that may produce behavioral reactions such as mounting an aggressive response or fleeing the threat. Fear in human beings may occur in response to a certain stimulus occurring in the present, or in anticipation or expectation of a future threat perceived as a risk to oneself. The fear response arises from the perception of danger leading to confrontation with or escape from/avoiding the threat, which in extreme cases of fear can be a freeze response.

<span class="mw-page-title-main">Stress (biology)</span> Organisms response to a stressor such as an environmental condition or a stimulus

Stress, whether physiological, biological or psychological, is an organism's response to a stressor such as an environmental condition. Stress is the body's method of reacting to a condition such as a threat, challenge or physical and psychological barrier. There are two hormones that an individual produces during a stressful situation, well known as adrenaline and cortisol. There are two kinds of stress hormone levels. Resting (basal) cortisol levels are normal everyday quantities that are essential for standard functioning. Reactive cortisol levels are increases in cortisol in response to stressors. Stimuli that alter an organism's environment are responded to by multiple systems in the body. In humans and most mammals, the autonomic nervous system and hypothalamic-pituitary-adrenal (HPA) axis are the two major systems that respond to stress.

Sociosexuality, sometimes called sociosexual orientation, is the individual difference in the willingness to engage in sexual activity outside of a committed relationship. Individuals who are more restricted sociosexually are less willing to engage in casual sex; they prefer greater love, commitment and emotional closeness before having sex with romantic partners. Individuals who are more unrestricted sociosexually are more willing to have casual sex and are more comfortable engaging in sex without love, commitment or closeness.

<span class="mw-page-title-main">Fluctuating asymmetry</span> Form of biological asymmetry

Fluctuating asymmetry (FA), is a form of biological asymmetry, along with anti-symmetry and direction asymmetry. Fluctuating asymmetry refers to small, random deviations away from perfect bilateral symmetry. This deviation from perfection is thought to reflect the genetic and environmental pressures experienced throughout development, with greater pressures resulting in higher levels of asymmetry. Examples of FA in the human body include unequal sizes (asymmetry) of bilateral features in the face and body, such as left and right eyes, ears, wrists, breasts, testicles, and thighs.

<span class="mw-page-title-main">Psychological adaptation</span>

A psychological adaptation is a functional, cognitive or behavioral trait that benefits an organism in its environment. Psychological adaptations fall under the scope of evolved psychological mechanisms (EPMs), however, EPMs refer to a less restricted set. Psychological adaptations include only the functional traits that increase the fitness of an organism, while EPMs refer to any psychological mechanism that developed through the processes of evolution. These additional EPMs are the by-product traits of a species’ evolutionary development, as well as the vestigial traits that no longer benefit the species’ fitness. It can be difficult to tell whether a trait is vestigial or not, so some literature is more lenient and refers to vestigial traits as adaptations, even though they may no longer have adaptive functionality. For example, xenophobic attitudes and behaviors, some have claimed, appear to have certain EPM influences relating to disease aversion, however, in many environments these behaviors will have a detrimental effect on a person's fitness. The principles of psychological adaptation rely on Darwin's theory of evolution and are important to the fields of evolutionary psychology, biology, and cognitive science.

Affective neuroscience is the study of how the brain processes emotions. This field combines neuroscience with the psychological study of personality, emotion, and mood. The basis of emotions and what emotions are remains an issue of debate within the field of affective neuroscience.

Social connection is the experience of feeling close and connected to others. It involves feeling loved, cared for, and valued, and forms the basis of interpersonal relationships.

"Connection is the energy that exists between people when they feel seen, heard and valued; when they can give and receive without judgement; and when they derive sustenance and strength from the relationship." —Brené Brown, Professor of social work at the University of Houston

Chronic stress is the physiological or psychological response induced by a long-term internal or external stressor. The stressor, either physically present or recollected, will produce the same effect and trigger a chronic stress response. There is a wide range of chronic stressors, but most entail relatively prolonged problems, conflicts and threats that people encounter on a daily basis. And several chronic stressors, including "neighbourhood environment, financial strain, interpersonal stress, work stress and caregiving.", have been identified as associated with disease and mortality.

Evolutionary approaches to depression are attempts by evolutionary psychologists to use the theory of evolution to shed light on the problem of mood disorders within the perspective of evolutionary psychiatry. Depression is generally thought of as dysfunction or a mental disorder, but its prevalence does not increase with age the way dementia and other organic dysfunction commonly does. Some researchers have surmised that the disorder may have evolutionary roots, in the same way that others suggest evolutionary contributions to schizophrenia, sickle cell anemia, psychopathy and other disorders. Psychology and psychiatry have not generally embraced evolutionary explanations for behaviors, and the proposed explanations for the evolution of depression remain controversial.

Social anxiety is the anxiety and fear specifically linked to being in social settings. Some categories of disorders associated with social anxiety include anxiety disorders, mood disorders, autism spectrum disorders, eating disorders, and substance use disorders. Individuals with higher levels of social anxiety often avert their gazes, show fewer facial expressions, and show difficulty with initiating and maintaining a conversation. Social anxiety commonly manifests itself in the teenage years and can be persistent throughout life; however, people who experience problems in their daily functioning for an extended period of time can develop social anxiety disorder. Trait social anxiety, the stable tendency to experience this anxiety, can be distinguished from state anxiety, the momentary response to a particular social stimulus. Half of the individuals with any social fears meet the criteria for social anxiety disorder. Age, culture, and gender impact the severity of this disorder. The function of social anxiety is to increase arousal and attention to social interactions, inhibit unwanted social behavior, and motivate preparation for future social situations.

<span class="mw-page-title-main">Disgust</span> Basic emotion

Disgust is an emotional response of rejection or revulsion to something potentially contagious or something considered offensive, distasteful or unpleasant. In The Expression of the Emotions in Man and Animals, Charles Darwin wrote that disgust is a sensation that refers to something revolting. Disgust is experienced primarily in relation to the sense of taste, and secondarily to anything which causes a similar feeling by sense of smell, touch, or vision. Musically sensitive people may even be disgusted by the cacophony of inharmonious sounds. Research has continually proven a relationship between disgust and anxiety disorders such as arachnophobia, blood-injection-injury type phobias, and contamination fear related obsessive–compulsive disorder.

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 a professor of psychology at the University of British Columbia.

<span class="mw-page-title-main">Trypophobia</span> Fear or disgust of objects with repetitive patterns of small holes or bumps

Trypophobia is an aversion to the sight of repetitive patterns or clusters of small holes or bumps. It is not officially recognized as a mental disorder, but may be diagnosed as a specific phobia if excessive fear and distress occur. Most affected people experience mainly disgust when they see trypophobic imagery. A minority of people experience the same level of fear and disgust, and a few express only disgust or fear.

Emotion perception refers to the capacities and abilities of recognizing and identifying emotions in others, in addition to biological and physiological processes involved. Emotions are typically viewed as having three components: subjective experience, physical changes, and cognitive appraisal; emotion perception is the ability to make accurate decisions about another's subjective experience by interpreting their physical changes through sensory systems responsible for converting these observed changes into mental representations. The ability to perceive emotion is believed to be both innate and subject to environmental influence and is also a critical component in social interactions. How emotion is experienced and interpreted depends on how it is perceived. Likewise, how emotion is perceived is dependent on past experiences and interpretations. Emotion can be accurately perceived in humans. Emotions can be perceived visually, audibly, through smell and also through bodily sensations and this process is believed to be different from the perception of non-emotional material.

<span class="mw-page-title-main">Human mating strategies</span> Courtship behavior of humans

In evolutionary psychology and behavioral ecology, human mating strategies are a set of behaviors used by individuals to select, attract, and retain mates. Mating strategies overlap with reproductive strategies, which encompass a broader set of behaviors involving the timing of reproduction and the trade-off between quantity and quality of offspring.

Some evolutionary theorists consider prejudice as having functional utility in evolutionary process. A number of evolutionary psychologists in particular posit that human psychology, including emotion and cognition, is influenced by evolutionary processes. These theorists argue that although psychological variation appears between individuals, the majority of our psychological mechanisms are adapted specifically to solve recurrent problems in our evolutionary history, including social problems.

Groups of animals and humans that live in places with high population density have an increased risk of disease prevalence. In looking at sociality and disease transmission, an examination of how social grouping strategies may reduce or increase the spread of disease is critical for the health of large groups of people. Social groups, community structures, and cultures affect the use of different strategies and behaviors to reduce the spread of disease.

Major depression is often associated or correlated with immune function dysregulation, and the two are thought to share similar physiological pathways and risk factors. Primarily seen through increased inflammation, this relationship is bidirectional with depression often resulting in increased immune response and illness resulting in prolonged sadness and lack of activity. This association is seen both long-term and short-term, with the presence of one often being accompanied by the other and both inflammation and depression often being co-morbid with other conditions.

Costly signaling theory in evolutionary psychology refers to uses of costly signaling theory and adaptationism in explanations for psychological traits and states. Often informed by the closely related fields of human behavioral ecology and cultural evolution, such explanations are predominantly focused on humans and emphasize the benefits of altering the perceptions of others and the need to do so in ways that are difficult to fake due to the widespread existence of adaptations which demand reliable information to avoid manipulation through dishonest signals.

Pathogen avoidance, also referred to as, parasite avoidance or pathogen disgust, refers to the theory that the disgust response, in humans, is an adaptive system that guides behavior to avoid infection caused by parasites such as viruses, bacteria, fungi, protozoa, helminth worms, arthropods and social parasites. Pathogen avoidance is a psychological mechanism associated with the behavioral immune system. Pathogen avoidance has been discussed as one of the three domains of disgust which also include sexual and moral disgust.

References

  1. Schaller M (2006). "Parasites, behavioral defenses, and the social psychological mechanisms through which cultures are evoked". Psychological Inquiry. 17 (2): 96–101. doi:10.1207/s15327965pli1702_2. S2CID   219729311.
  2. 1 2 3 Schaller M, Duncan LA (2007). "The behavioral immune system: Its evolution and social psychological implications". In Forgas JP, Haselton MG, von Hippel W (eds.). Evolution and the social mind: Evolutionary psychology and social cognition. New York: Psychology Press. pp. 293–307.
  3. Schaller M, Park JH (2011). "The behavioral immune system (and why it matters)". Current Directions in Psychological Science. 20 (2): 99–103. CiteSeerX   10.1.1.459.1601 . doi:10.1177/0963721411402596. S2CID   39930315.
  4. Dantzer R (March 2001). "Cytokine-induced sickness behavior: where do we stand?". Brain, Behavior, and Immunity. 15 (1): 7–24. doi:10.1006/brbi.2000.0613. PMID   11259077. S2CID   3187017.
  5. Hart BL (June 1988). "Biological basis of the behavior of sick animals". Neuroscience and Biobehavioral Reviews. 12 (2): 123–37. doi:10.1016/s0149-7634(88)80004-6. PMID   3050629. S2CID   17797005.
  6. Conner EM, Grisham MB (April 1996). "Inflammation, free radicals, and antioxidants". Nutrition. 12 (4): 274–7. doi:10.1016/s0899-9007(96)00000-8. PMID   8862535.
  7. Khansari N, Shakiba Y, Mahmoudi M (January 2009). "Chronic inflammation and oxidative stress as a major cause of age-related diseases and cancer". Recent Patents on Inflammation & Allergy Drug Discovery. 3 (1): 73–80. doi:10.2174/187221309787158371. PMID   19149749.
  8. Murray DR, Schaller M (2016). "The Behavioral Immune System". Advances in Experimental Social Psychology. Vol. 53. Elsevier. pp. 75–129. doi:10.1016/bs.aesp.2015.09.002. ISBN   978-0-12-804737-8.
  9. 1 2 Schaller M, Park JH (April 2011). "The Behavioral Immune System (and Why It Matters)". Current Directions in Psychological Science. 20 (2): 99–103. doi:10.1177/0963721411402596. ISSN   0963-7214. S2CID   39930315.
  10. 1 2 Schaller M (December 2011). "The behavioural immune system and the psychology of human sociality". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 366 (1583): 3418–26. doi:10.1098/rstb.2011.0029. PMC   3189350 . PMID   22042918.
  11. 1 2 Oaten M, Stevenson RJ, Case TI (March 2009). "Disgust as a disease-avoidance mechanism". Psychological Bulletin. 135 (2): 303–21. doi:10.1037/a0014823. PMID   19254082.
  12. 1 2 3 4 Murray DR, Prokosch ML, Airington Z (2019-02-07). "PsychoBehavioroimmunology: Connecting the Behavioral Immune System to Its Physiological Foundations". Frontiers in Psychology. 10: 200. doi: 10.3389/fpsyg.2019.00200 . PMC   6378957 . PMID   30804853.
  13. Regenbogen C, Axelsson J, Lasselin J, Porada DK, Sundelin T, Peter MG, et al. (June 2017). "Behavioral and neural correlates to multisensory detection of sick humans". Proceedings of the National Academy of Sciences of the United States of America. 114 (24): 6400–6405. doi: 10.1073/pnas.1617357114 . PMC   5474783 . PMID   28533402.
  14. Olsson MJ, Lundström JN, Kimball BA, Gordon AR, Karshikoff B, Hosseini N, et al. (March 2014). "The scent of disease: human body odor contains an early chemosensory cue of sickness". Psychological Science. 25 (3): 817–23. doi:10.1177/0956797613515681. PMID   24452606. S2CID   14530226.
  15. Stevenson RJ, Repacholi BM (2005). "Does the source of an interpersonal odour affect disgust? A disease risk model and its alternatives". European Journal of Social Psychology. 35 (3): 375–401. doi:10.1002/ejsp.263. ISSN   0046-2772.
  16. Tybur JM, Bryan AD, Magnan RE, Hooper AE (April 2011). "Smells like safe sex: olfactory pathogen primes increase intentions to use condoms". Psychological Science. 22 (4): 478–80. doi:10.1177/0956797611400096. PMID   21350181. S2CID   31099982.
  17. Schnall S, Haidt J, Clore GL, Jordan AH (August 2008). "Disgust as embodied moral judgment". Personality & Social Psychology Bulletin. 34 (8): 1096–109. doi:10.1177/0146167208317771. PMC   2562923 . PMID   18505801.
  18. Fay AJ, Bovier ER (2018-02-24). "Testing a Curvilinear Relationship between Chemosensory Responsivity and Avoidance Motivation". Adaptive Human Behavior and Physiology. 4 (2): 207–222. doi:10.1007/s40750-018-0088-1. ISSN   2198-7335. S2CID   148883832.
  19. Tybur JM, Laakasuo M, Ruff J, Klauke F (September 2016). "How pathogen cues shape impressions of foods: the omnivore's dilemma and functionally specialized conditioning". Evolution and Human Behavior. 37 (5): 376–386. doi:10.1016/j.evolhumbehav.2016.03.002. ISSN   1090-5138.
  20. Al-Shawaf L, Lewis DM, Alley TR, Buss DM (February 2015). "Mating strategy, disgust, and food neophobia". Appetite. 85: 30–5. doi:10.1016/j.appet.2014.10.029. hdl: 11693/22547 . PMID   25450899. S2CID   14110094.
  21. 1 2 Reid SA, Zhang J, Anderson GL, Gasiorek J, Bonilla D, Peinado S (September 2012). "Parasite primes make foreign-accented English sound more distant to people who are disgusted by pathogens (but not by sex or morality)". Evolution and Human Behavior. 33 (5): 471–478. doi:10.1016/j.evolhumbehav.2011.12.009. ISSN   1090-5138.
  22. Hunt DF, Cannell G, Davenhill NA, Horsford SA, Fleischman DS, Park JH (July 2017). "Making your skin crawl: The role of tactile sensitivity in disease avoidance" (PDF). Biological Psychology. 127: 40–45. doi:10.1016/j.biopsycho.2017.04.017. PMID   28478137. S2CID   7894884.
  23. Park JH (August 2015). "Introversion and human-contaminant disgust sensitivity predict personal space" (PDF). Personality and Individual Differences. 82: 185–187. doi:10.1016/j.paid.2015.03.030. hdl: 1983/aa8c5c1c-f834-432d-9885-b5d44fff50d4 . ISSN   0191-8869.
  24. Haselton MG, Nettle D (February 2006). "The paranoid optimist: an integrative evolutionary model of cognitive biases". Personality and Social Psychology Review. 10 (1): 47–66. doi:10.1207/s15327957pspr1001_3. PMID   16430328. S2CID   5725102.
  25. Nesse RM (2018-12-04). "The smoke detector principle: Signal detection and optimal defense regulation". Evolution, Medicine, and Public Health. 2019 (1): 1. doi:10.1093/emph/eoy034. PMC   6343816 . PMID   30697424.
  26. 1 2 3 4 5 6 7 8 9 Ackerman JM, Hill SE, Murray DR (2018-01-26). "The behavioral immune system: Current concerns and future directions". Social and Personality Psychology Compass. 12 (2): e12371. doi: 10.1111/spc3.12371 . hdl: 2027.42/142457 . ISSN   1751-9004.
  27. 1 2 Duncan LA, Schaller M (October 27, 2009). "Prejudicial Attitudes Toward Older Adults May Be Exaggerated When People Feel Vulnerable to Infectious Disease: Evidence and Implications". Analyses of Social Issues and Public Policy. 9 (1): 97–115. doi:10.1111/j.1530-2415.2009.01188.x.
  28. 1 2 3 Miller SL, Maner JK (June 2012). "Overperceiving disease cues: the basic cognition of the behavioral immune system". Journal of Personality and Social Psychology. 102 (6): 1198–213. doi:10.1037/a0027198. PMID   22329656.
  29. 1 2 Schaller M, Park J, Faulkner J (January 2003). "Prehistoric dangers and contemporary prejudices". European Review of Social Psychology. 14 (1): 105–137. doi:10.1080/10463280340000036. ISSN   1046-3283. S2CID   30987296.
  30. Lund EM, Miller SL (July 2014). "Is obesity un-American? Disease concerns bias implicit perceptions of national identity". Evolution and Human Behavior. 35 (4): 336–340. doi:10.1016/j.evolhumbehav.2014.03.004. ISSN   1090-5138.
  31. 1 2 Ackerman JM, Becker DV, Mortensen CR, Sasaki T, Neuberg SL, Kenrick DT (May 2009). "A pox on the mind: Disjunction of attention and memory in the processing of physical disfigurement". Journal of Experimental Social Psychology. 45 (3): 478–485. doi:10.1016/j.jesp.2008.12.008. PMC   2699287 . PMID   19578547.
  32. Miller SL, Maner JK (December 2011). "Sick body, vigilant mind: the biological immune system activates the behavioral immune system". Psychological Science. 22 (12): 1467–71. doi:10.1177/0956797611420166. PMID   22058109. S2CID   206585861.
  33. Lieberman D, Patrick C (2014). "Are the behavioral immune system and pathogen disgust identical?". Evolutionary Behavioral Sciences. 8 (4): 244–250. doi:10.1037/ebs0000018. ISSN   2330-2933.
  34. Darwin C (2009). "Disdain — Contempt — Disgust — Guilt — Pride, Etc. — Helplessness — Patience — Affirmation and Negation". In Darwin F (ed.). The Expression of the Emotions in Man and Animals. Cambridge: Cambridge University Press. pp. 265–292. doi:10.1017/cbo9780511694110.013. ISBN   978-0-511-69411-0.
  35. 1 2 Cepon-Robins TJ, Blackwell AD, Gildner TE, Liebert MA, Urlacher SS, Madimenos FC, et al. (February 2021). "Pathogen disgust sensitivity protects against infection in a high pathogen environment". Proceedings of the National Academy of Sciences of the United States of America. 118 (8): e2018552118. doi: 10.1073/pnas.2018552118 . PMC   7923589 . PMID   33597300.
  36. Schaller M, Neuberg SL (2012). "Danger, Disease, and the Nature of Prejudice(s)". Advances in Experimental Social Psychology. Vol. 46. Elsevier. pp. 1–54. doi:10.1016/b978-0-12-394281-4.00001-5. ISBN   978-0-12-394281-4.
  37. Schaller M, Park JH, Kenrick DT (2007-04-05). "Human evolution and social cognition". Oxford Handbooks Online: 491–504. doi:10.1093/oxfordhb/9780198568308.013.0033. ISBN   978-0198568308.
  38. Curtis V, de Barra M, Aunger R (February 2011). "Disgust as an adaptive system for disease avoidance behaviour". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 366 (1563): 389–401. doi:10.1098/rstb.2011.0002. PMC   3013466 . PMID   21199843.
  39. 1 2 Tybur JM, Lieberman D, Kurzban R, DeScioli P (January 2013). "Disgust: evolved function and structure". Psychological Review. 120 (1): 65–84. doi:10.1037/a0030778. PMID   23205888.
  40. 1 2 Duncan LA, Schaller M, Park JH (October 2009). "Perceived vulnerability to disease: Development and validation of a 15-item self-report instrument". Personality and Individual Differences. 47 (6): 541–6. doi:10.1016/j.paid.2012.08.021.
  41. Murray DR, Jones DN, Schaller M (January 2013). "Perceived threat of infectious disease and its implications for sexual attitudes". Personality and Individual Differences. 54 (1): 103–108. doi:10.1016/j.paid.2012.08.021. ISSN   0191-8869.
  42. 1 2 Schaller M, Murray DR (July 2008). "Pathogens, personality, and culture: disease prevalence predicts worldwide variability in sociosexuality, extraversion, and openness to experience". Journal of Personality and Social Psychology. 95 (1): 212–21. CiteSeerX   10.1.1.476.4335 . doi:10.1037/0022-3514.95.1.212. PMID   18605861.
  43. Tybur JM, Bryan AD, Lieberman D, Hooper AE, Merriman LA (August 2011). "Sex differences and sex similarities in disgust sensitivity". Personality and Individual Differences. 51 (3): 343–348. doi:10.1016/j.paid.2011.04.003. ISSN   0191-8869.
  44. 1 2 Park JH, Schaller M, Crandall CS (November 2007). "Pathogen-avoidance mechanisms and the stigmatization of obese people". Evolution and Human Behavior. 28 (6): 410–414. doi:10.1016/j.evolhumbehav.2007.05.008. ISSN   1090-5138.
  45. Curtis V, Biran A (2001). "Dirt, disgust, and disease. Is hygiene in our genes?". Perspectives in Biology and Medicine. 44 (1): 17–31. doi:10.1353/pbm.2001.0001. PMID   11253302. S2CID   15675303.
  46. 1 2 Gangestad SW, Buss DM (March 1993). "Pathogen prevalence and human mate preferences". Ethology and Sociobiology. 14 (2): 89–96. doi:10.1016/0162-3095(93)90009-7. hdl: 2027.42/30928 . ISSN   0162-3095.
  47. 1 2 Hill SE, Prokosch ML, DelPriore DJ (August 2015). "The impact of perceived disease threat on women's desire for novel dating and sexual partners: is variety the best medicine?". Journal of Personality and Social Psychology. 109 (2): 244–61. doi:10.1037/pspi0000024. PMID   26030057.
  48. Jones BC, Feinberg DR, Watkins CD, Fincher CL, Little AC, DeBruine LM (2012-10-23). "Pathogen disgust predicts women's preferences for masculinity in men's voices, faces, and bodies". Behavioral Ecology. 24 (2): 373–379. doi: 10.1093/beheco/ars173 . ISSN   1465-7279.
  49. 1 2 Lee AJ, Zietsch BP (December 2011). "Experimental evidence that women's mate preferences are directly influenced by cues of pathogen prevalence and resource scarcity". Biology Letters. 7 (6): 892–5. doi:10.1098/rsbl.2011.0454. PMC   3210674 . PMID   21697166.
  50. Hugenberg K, Young SG, Sacco DF, Bernstein MJ (2011-07-28). "Social Categorization Influences Face Perception and Face Memory". Oxford Handbooks Online. doi:10.1093/oxfordhb/9780199559053.013.0013.
  51. Makhanova A, Miller SL, Maner JK (January 2015). "Germs and the out-group: Chronic and situational disease concerns affect intergroup categorization". Evolutionary Behavioral Sciences. 9 (1): 8–19. doi:10.1037/ebs0000028. ISSN   2330-2933.
  52. Inbar, Yoel; Pizarro, David (2014), "Pollution and Purity in Moral and Political Judgment", Advances in Experimental Moral Psychology, Bloomsbury Academic, pp. 111–129, doi:10.5040/9781472594150.ch-006, ISBN   978-1-4725-0938-3
  53. Peng M, Chang L, Zhou R (March 2013). "Physiological and behavioral responses to strangers compared to friends as a source of disgust". Evolution and Human Behavior. 34 (2): 94–98. doi:10.1016/j.evolhumbehav.2012.10.002. ISSN   1090-5138.
  54. Prokosch ML, Gassen J, Ackerman JM, Hill SE (October 2019). "Caution in the time of cholera: Pathogen threats decrease risk tolerance". Evolutionary Behavioral Sciences. 13 (4): 311–334. doi:10.1037/ebs0000160. ISSN   2330-2933. S2CID   92163234.
  55. Sacco DF, Young SG, Hugenberg K (December 2014). "Balancing competing motives: adaptive trade-offs are necessary to satisfy disease avoidance and interpersonal affiliation goals". Personality & Social Psychology Bulletin. 40 (12): 1611–23. doi:10.1177/0146167214552790. PMID   25278107. S2CID   8082873.
  56. 1 2 Huang JY, Ackerman JM, Newman GE (October 2017). "Catching (Up with) Magical Contagion: A Review of Contagion Effects in Consumer Contexts". Journal of the Association for Consumer Research. 2 (4): 430–443. doi:10.1086/693533. ISSN   2378-1815. S2CID   51791428.
  57. Mortensen CR, Becker DV, Ackerman JM, Neuberg SL, Kenrick DT (March 2010). "Infection breeds reticence: the effects of disease salience on self-perceptions of personality and behavioral avoidance tendencies". Psychological Science. 21 (3): 440–7. doi:10.1177/0956797610361706. hdl: 1721.1/67706 . PMID   20424082. S2CID   2791764.
  58. 1 2 White AE, Kenrick DT, Neuberg SL (December 2013). "Beauty at the ballot box: disease threats predict preferences for physically attractive leaders". Psychological Science. 24 (12): 2429–36. doi:10.1177/0956797613493642. PMID   24121414. S2CID   20502884.
  59. Lee AJ, Brooks RC, Potter KJ, Zietsch BP (November 2015). "Pathogen disgust sensitivity and resource scarcity are associated with mate preference for different waist-to-hip ratios, shoulder-to-hip ratios, and body mass index". Evolution and Human Behavior. 36 (6): 480–488. doi:10.1016/j.evolhumbehav.2015.07.002. hdl: 1893/28703 . ISSN   1090-5138.
  60. Little AC, DeBruine LM, Jones BC (July 2011). "Exposure to visual cues of pathogen contagion changes preferences for masculinity and symmetry in opposite-sex faces". Proceedings. Biological Sciences. 278 (1714): 2032–9. doi:10.1098/rspb.2010.1925. PMC   3107643 . PMID   21123269.
  61. Navarrete CD, Fessler DM (July 2006). "Disease avoidance and ethnocentrism: the effects of disease vulnerability and disgust sensitivity on intergroup attitudes". Evolution and Human Behavior. 27 (4): 270–282. doi:10.1016/j.evolhumbehav.2005.12.001. ISSN   1090-5138.
  62. Mortensen CR, Becker DV, Ackerman JM, Neuberg SL, Kenrick DT (March 2010). "Infection breeds reticence: the effects of disease salience on self-perceptions of personality and behavioral avoidance tendencies". Psychological Science. 21 (3): 440–7. doi:10.1177/0956797610361706. hdl: 1721.1/67706 . PMID   20424082. S2CID   2791764.
  63. Huang JY, Sedlovskaya A, Ackerman JM, Bargh JA (December 2011). "Immunizing against prejudice: effects of disease protection on attitudes toward out-groups". Psychological Science. 22 (12): 1550–6. doi:10.1177/0956797611417261. hdl: 1721.1/77620 . PMID   22058107. S2CID   18413566.
  64. 1 2 Faulkner J, Schaller M, Park JH, Duncan LA (2004). "Evolved Disease–Avoidance Mechanisms and Contemporary Xenophobic Attitudes". Group Processes and Intergroup Relations. 7 (4): 333–53. CiteSeerX   10.1.1.1018.9323 . doi:10.1177/1368430204046142. S2CID   28558930.
  65. Crandall CS, Moriarty D (March 1995). "Physical illness stigma and social rejection". The British Journal of Social Psychology. 34 ( Pt 1) (1): 67–83. doi:10.1111/j.2044-8309.1995.tb01049.x. PMID   7735733.
  66. Park JH, Faulkner J, Schaller M (June 2003). "Evolved disease-avoidance processes and contemporary anti-social behavior: Prejudicial attitudes and avoidance of people with physical disabilities". Journal of Nonverbal Behavior. 27 (2): 65–87. doi:10.1023/A:1023910408854. ISSN   1573-3653. S2CID   41615132.
  67. Park J, Schaller M, Crandall CS (2007). "Pathogen-avoidance mechanisms and the stigmatization of obese people" (PDF). Evolution and Human Behavior. 28 (6): 410–4. doi:10.1016/j.evolhumbehav.2007.05.008.
  68. 1 2 Navarrete CD, Fessler D, Eng S (2007). "Elevated ethnocentrism in the first trimester of pregnancy" (PDF). Evolution and Human Behavior. 28 (1): 60–5. doi:10.1016/j.evolhumbehav.2006.06.002.[ dead link ]
  69. Murray DR, Schaller M (2011-11-20). "Threat(s) and conformity deconstructed: Perceived threat of infectious disease and its implications for conformist attitudes and behavior". European Journal of Social Psychology. 42 (2): 180–188. doi:10.1002/ejsp.863. ISSN   0046-2772.
  70. Wu BP, Chang L (July 2012). "The social impact of pathogen threat: How disease salience influences conformity". Personality and Individual Differences. 53 (1): 50–54. doi:10.1016/j.paid.2012.02.023. ISSN   0191-8869.
  71. Haidt J, McCauley C, Rozin P (1994). "Disgust Scale". PsycTESTS Dataset. doi:10.1037/t12177-000.
  72. 1 2 3 4 Fincher CL, Thornhill R, Murray DR, Schaller M (June 2008). "Pathogen prevalence predicts human cross-cultural variability in individualism/collectivism". Proceedings. Biological Sciences. 275 (1640): 1279–85. doi:10.1098/rspb.2008.0094. PMC   2602680 . PMID   18302996.
  73. Murray DR, Schaller M, Suedfeld P (2013-05-01). "Pathogens and politics: further evidence that parasite prevalence predicts authoritarianism". PLOS ONE. 8 (5): e62275. Bibcode:2013PLoSO...862275M. doi: 10.1371/journal.pone.0062275 . PMC   3641067 . PMID   23658718.
  74. Terrizzi JA, Shook NJ, McDaniel MA (March 2013). "The behavioral immune system and social conservatism: a meta-analysis". Evolution and Human Behavior. 34 (2): 99–108. doi:10.1016/j.evolhumbehav.2012.10.003. ISSN   1090-5138. S2CID   11812927.
  75. Fincher CL, Thornhill R (November 2008). "Assortative sociality, limited dispersal, infectious disease and the genesis of the global pattern of religion diversity". Proceedings. Biological Sciences. 275 (1651): 2587–94. doi:10.1098/rspb.2008.0688. PMC   2605802 . PMID   18664438.
  76. 1 2 Fincher CL, Thornhill R (April 2012). "Parasite-stress promotes in-group assortative sociality: the cases of strong family ties and heightened religiosity" (PDF). The Behavioral and Brain Sciences. 35 (2): 61–79. doi:10.1017/s0140525x11000021. PMID   22289223. S2CID   54624893.
  77. Thornhill R, Fincher CL (July 2013). "Commentary on Hackman, J., & Hruschka, D. (2013). Fast life histories, not pathogens, account for state-level variation in homicide, child maltreatment, and family ties in the U.S. Evolution and Human Behavior, 34,118–124". Evolution and Human Behavior. 34 (4): 314–315. doi:10.1016/j.evolhumbehav.2013.03.006. ISSN   1090-5138.
  78. Van de Vliert E, Postmes T (April 2012). "Climato-economic livability predicts societal collectivism and political autocracy better than parasitic stress does". The Behavioral and Brain Sciences. 35 (2): 94–5. doi:10.1017/s0140525x11001075. PMID   22289160. S2CID   13449531.
  79. Currie TE, Mace R (April 2012). "Analyses do not support the parasite-stress theory of human sociality" (PDF). The Behavioral and Brain Sciences. 35 (2): 83–5. doi:10.1017/s0140525x11000963. PMID   22289294. S2CID   302233.
  80. Hruschka DJ, Henrich J (2013-05-21). "Institutions, parasites and the persistence of in-group preferences". PLOS ONE. 8 (5): e63642. Bibcode:2013PLoSO...863642H. doi: 10.1371/journal.pone.0063642 . PMC   3660589 . PMID   23704926.
  81. Schaller M, Miller GE, Gervais WM, Yager S, Chen E (May 2010). "Mere visual perception of other people's disease symptoms facilitates a more aggressive immune response". Psychological Science. 21 (5): 649–52. doi:10.1177/0956797610368064. PMID   20483842. S2CID   58423.
  82. Stevenson RJ, Hodgson D, Oaten MJ, Barouei J, Case TI (July 2011). "The effect of disgust on oral immune function". Psychophysiology. 48 (7): 900–7. doi:10.1111/j.1469-8986.2010.01165.x. PMID   21166686.
  83. Stevenson RJ, Hodgson D, Oaten MJ, Moussavi M, Langberg R, Case TI, Barouei J (October 2012). "Disgust elevates core body temperature and up-regulates certain oral immune markers". Brain, Behavior, and Immunity. 26 (7): 1160–8. doi:10.1016/j.bbi.2012.07.010. PMID   22841694. S2CID   34237534.
  84. Stevenson RJ, Hodgson D, Oaten MJ, Sominsky L, Mahmut M, Case TI (2015-07-01). "Oral Immune Activation by Disgust and Disease-Related Pictures". Journal of Psychophysiology. 29 (3): 119–129. doi:10.1027/0269-8803/a000143. ISSN   0269-8803.
  85. Gassen J, Prokosch ML, Makhanova A, Eimerbrink MJ, White JD, Proffitt Leyva RP, et al. (2018-09-20). "Behavioral immune system activity predicts downregulation of chronic basal inflammation". PLOS ONE. 13 (9): e0203961. Bibcode:2018PLoSO..1303961G. doi: 10.1371/journal.pone.0203961 . PMC   6147464 . PMID   30235317.
  86. Huang JY, Sedlovskaya A, Ackerman JM, Bargh JA (December 2011). "Immunizing against prejudice: effects of disease protection on attitudes toward out-groups". Psychological Science. 22 (12): 1550–6. doi:10.1177/0956797611417261. hdl: 1721.1/77620 . PMID   22058107. S2CID   18413566.
  87. 1 2 3 4 5 Schrock JM, Snodgrass JJ, Sugiyama LS (January 2020). "Lassitude: The emotion of being sick". Evolution and Human Behavior. 41 (1): 44–57. doi:10.1016/j.evolhumbehav.2019.09.002. ISSN   1090-5138. S2CID   203480861.
  88. Moran JB, Goh JX, Kerry N, Murray DR (April 2021). "Outbreaks and Outgroups: Three Tests of the Relationship Between Disease Avoidance Motives and Xenophobia During an Emerging Pandemic". Evolutionary Psychological Science. 7 (4): 419–429. doi:10.1007/s40806-021-00283-z. PMC   8060690 . PMID   33903849.
  89. Makhanova A, Shepherd MA (December 2020). "Behavioral immune system linked to responses to the threat of COVID-19". Personality and Individual Differences. 167: 110221. doi:10.31234/osf.io/6dq3g. PMC   7328593 . PMID   32834281.