Domain-specific variation in disgust sensitivity across the menstrual cycle

Influence of female sex hormones on proactive behavioral and physiological immune parameters

Women may be more susceptible to infections in the luteal phase, supposedly as a consequence of the hormone progesterone and its immunosuppressive action. While immunosuppression may be important for successful oocyte implantation and pregnancy, it makes women more vulnerable to pathogens. According to theory, to compensate for reduced immunocompetence, women in the luteal phase exhibit proactive behavioral responses, such as disgust and avoidance of disease-associated stimuli, to minimize contagion risk. However, previous studies yielded inconsistent results, and did not account for accompanying proactive immune responses, like the increase of secretory immunoglobin A (sIgA). Here, we assessed the proactive immune response and feelings of disgust associated with disease cues in the comparison of 61 woman with a natural menstrual cycle (31 in the follicular and 30 in the luteal phase) and 20 women taking hormonal contraception (HC). Women rated disease vulnerability and disgust propensity, watched a video displaying people with respiratory symptoms, which was evaluated for its disgust-evoking potential and contagiousness, and provided saliva samples for hormone and sIgA analysis. Women with HC reported a heightened vulnerability to disease compared to naturally cycling women, whereas both the feeling of disgust and the sIgA increase elicited by the disease video were similar across groups, regardless of progesterone. We found a u-shaped relationship between progesterone and baseline sIgA in naturally cycling women, with its nadir during ovulation. Overall, our data do not support a compensatory relationship between the proposed progesterone-induced immunosuppression and heightened disgust or a proactive sIgA response.

Flesh Without Blood: The Public Health Benefits of Lab-Grown Meat

Synthetic meat made from animal cells will transform how we eat. It will reduce suffering by eliminating the need to raise and slaughter animals. But it will also have big public health benefits if it becomes widely consumed. In this paper, we discuss how "clean meat" can reduce the risks associated with intensive animal farming, including antibiotic resistance, environmental pollution, and zoonotic viral diseases like influenza and coronavirus. Since the most common objection to clean meat is that some people find it "disgusting" or "unnatural," we explore the psychology of disgust to find possible counter-measures. We argue that the public health benefits of clean meat give us strong moral reasons to promote its development and consumption in a way that the public is likely to support. We end by depicting the change from farmed animals to clean meat as a collective action problem and suggest that social norms rather than coercive laws should be employed to solve the problem.

Spit, Disgust, and Parasite Stress Theory: A Message Experiment

Public health interventions targeting coughing and spitting during the Tuberculosis and 1918 flu epidemics were largely successful. Specifically, public health officials' messaging framed the behavior of spitting as repulsive and endangering to others, prompting an elicitation of disgust. Anti-spitting campaigns - messaging that focuses on the threat of spit or sputum - have long been common during pandemics and manifested once again to combat the spread of COVID-19. Yet, few scholars have theorized if and how anti-spitting campaigns function to change behavior. One possibility is parasite stress theory, which posits that human behavior is driven by a desire to avoid pathogenic threats like spit. The application of these types of disgust appeals in public health messaging remains understudied and warrants exploration. To test the applicability of the parasite stress theory, our message experiment with US adults (N = 488) examined reactions to anti-spit messages that varied in visual disgust (low and high). For more highly educated respondents, the high disgust appeal directly decreased spitting intentions, and this relationship was stronger for individuals with higher levels of pathogen and moral disgust. Given the importance of public messaging during pandemics, future research should continue to examine the efficacy and theoretical underpinnings of specific disgust appeals.

Pandemic elevates sensitivity to moral disgust but not pathogen disgust

The behavioral immune system, with disgust as its motivational part, serves as the first line of defense in organisms' protection against pathogens. Laboratory studies indicate that disgust sensitivity adaptively adjusts to simulated environmental threat, but whether disgust levels similarly change in response to real-life threats, such as a pandemic, remains largely unknown. In a preregistered within-subject study, we tested whether the threat posed by the Covid-19 pandemic would lead to increased perceived disgust. The perception of threat was induced by testing during two phases of the Covid-19 pandemic (periods of high vs. low pathogen threat). We found heightened levels of moral disgust during a "wave" of the pandemic, but the effect was not observed in the domain of pathogen or sexual disgust. Moreover, the age of respondents and levels of trait anxiety were positively associated with pathogen and moral disgust, suggesting that variation in disgust sensitivity may be based chiefly on stable characteristics.

Longitudinal changes in disgust sensitivity during pregnancy and the early postpartum period, and the role of recent health problems

Disgust is an essential part of the behavioral immune system, protecting the individual from infection. According to the Compensatory Prophylaxis Hypothesis (CPH), disgust sensitivity increases in times of immunosuppression, potentially including pregnancy. We aimed to replicate a previous study observing longitudinal changes in disgust sensitivity in pregnant women. Additionally, for the first time, we explored how recent health problems influence these changes. To do this, we obtained disgust sensitivity measures from 94 women in each trimester and in early postpartum. In contrast to the original study, where disgust sensitivity was highest in the first trimester, we found that overall and animal reminder disgust increased across pregnancy and after birth. In line with the CPH, women who were recently sick in the first trimester had elevated disgust sensitivity at that time. Although disgust sensitivity was significantly higher in the second trimester and postpartum period compared to the first trimester in mothers pregnant with a male fetus, the overall results regarding the effect of fetus sex on disgust sensitivity were mixed. It seems that changing levels of disgust sensitivity during pregnancy and postpartum result from a suite of physiological and psychological changes that occur during this sensitive period of a woman's life.

Disgust sensitivity in early pregnancy as a response to high pathogen risk

Introduction

Considered a part of the behavioral immune system (BIS), disgust sensitivity is expected to be adjusting as a response to the actual level of the environmental health risks.

Methods

In this preregistered study, we tested the hypothesis that disgust sensitivity would be higher during the COVID-19 pandemic compared to the pre-pandemic period in pregnant women. In this between-subject study with a longitudinal trend design, we administered the Disgust Scale-Revised to 200 pregnant women before the pandemic and to 350 pregnant women during the pandemic.

Results

We found a small but significant effect of the pandemic on disgust sensitivity, such that higher disgust sensitivity was found in women pregnant during the pandemic. This effect was stronger in primiparae, however, the interaction between parity and the pandemic period was not significant. Disgust sensitivity decreased with age. No differences in terms of nausea and vomiting were found between the women pregnant before and during the pandemic.

Discussion

Our findings indicate that although BIS is presumed to function as a complex mechanism to prevent health-threatening behaviors, its activation in pregnant women during the COVID-19 pandemic is rather weak.

The psychometric properties and gender invariance of the Italian version of the Perceived Vulnerability to Disease Questionnaire (I-PVDQ) during the COVID-19 pandemic

BACKGROUND

The Perceived Vulnerability to Disease Questionnaire (PVDQ) measures beliefs associated with personal susceptibility to infectious diseases and behaviors or perceptions in the presence of potential risk of pathogen transmission. Given the onset of the Severe Acute Respiratory Syndrome Coronavirus 2 global pandemic, otherwise known as the COVID-19 pandemic, the construct being measured may function differently based on affective, behavioral, and cognitive changes along with the need to change norms and lifestyles in a global context. The present study aims to test the psychometric properties and the gender invariance of the Italian adaptation of the PVDQ to confirm that the scale can be used with Italian-speaking people, and that it functions effectively during a pandemic.

METHODS

A total of 509 participants filled out an online questionnaire including the Italian version of the I-PVDQ (I-PVDQ) and several measures of psychological constructs. Reliability and factor analyses (single and multigroup) were conducted. Bayesian correlation tests and Bayesian independent sample t-tests were used to assess the validity of I-PVDQ.

RESULTS

Exploratory factor analysis supported the two-factor structure of the I-PVDQ, and factor loadings loaded appropriately onto perceived infectability (PI) and germ aversion (GA). In terms of invariance, the scale showed configural, metric, scalar, and strict invariance across genders. Decisive evidence in favor of correlation with the measure of COVID-19 related fears for both PI and GA was found. There was strong evidence for observed correlations with COVID-19 related constructs such as intolerance to uncertainty, psychological inflexibility, resilience, stress, and anxiety. Women showed higher GA than men, while there were no gender differences in PI.

CONCLUSIONS

Taken together, these results suggest that the I-PVDQ confirms the psychometric properties of the original version and that can be used to detect PVD when it is affected by environmental circumstances since its functioning is preserved during a pandemic.

The Effect of Menstrual Cycle Phases on Approach-Avoidance Behaviors in Women: Evidence from Conscious and Unconscious Processes

The menstrual cycle affects women’s emotional states, with estrogen and progesterone having predominant roles. However, it remains unclear whether the phases of the menstrual cycle also affect women’s motivational behaviors. In this study, the main aim was to investigate how the menstrual cycle influences approach–avoidance behavior under conditions of conscious versus unconscious processing of emotions. Briefly, after recruitment by advertisement and screening with a menstrual cycle survey questionnaire, 27 naturally cycling, healthy women participated in an improved “manikin task” and were presented both positive and negative emotional stimuli during early follicular, late follicular, and mid-luteal phases. Estrogen and progesterone levels were measured. Women in the late follicular phase exhibited the shortest response times for approaching positive stimuli, while women in the mid-luteal phase exhibited the shortest response times for avoiding negative stimuli. Estrogen and progesterone levels significantly correlated with the speed of the approach–avoidance responses observed for the women, indicating the important role that sex hormones have in mediating emotionally motivated behavior. Overall, these findings suggest that the menstrual cycle has strong and specific influences on women’s approach–avoidance behaviors that are in part mediated by estrogen and progesterone. By identifying characteristics of these behaviors in the late follicular and mid-luteal phases, greater insight can be provided to women regarding the physiological influences of the menstrual cycle on their personal growth and security.

Hormones, ovulatory cycle phase and pathogen disgust: A longitudinal investigation of the Compensatory Prophylaxis Hypothesis

Multiple studies have argued that disgust, especially pathogen disgust and contamination sensitivity, change across women's ovulatory cycle, with higher levels in the luteal phase due to an increase in progesterone levels. According to the Compensatory Prophylaxis Hypothesis (CPH), women have a higher disgust sensitivity to pathogen cues when in the luteal phase (or when progesterone levels are higher), because progesterone is associated with suppressed immune responses. Evidence for this hypothesis is rather mixed and uncertain, as the largest study conducted so far reported no compelling evidence for an association between progesterone levels and pathogen disgust. Further, ovulatory cycle research has been criticized for methodological shortcomings, such as invalid cycle phase estimates, no direct hormone assessments, small sample sizes or between-subjects studies. To address these issues and to contribute to the literature, we employed a large, within-subjects design (N = 257 with four sessions each), assessments of salivary hormone levels and cycle phase estimates based on luteinizing hormone tests. A variety of multilevel models suggest no compelling evidence that self-reported pathogen disgust or contamination sensitivity is upregulated in the luteal phase or tracks changes in women's hormone levels. We further found no compelling evidence for between-subjects associations of pathogen disgust or contamination sensitivity and hormone levels. Results remain robust across different analytical decisions (e.g. in a subsample of women reporting feeling sick). We discuss explanations for our results, limitations of the current study and provide directions for future research.

Behavioral Responses to Familiar Versus Unfamiliar Older People as a Source of Disgust

Disgust, as a part of the behavioral immune system, leads people to avoid behaviors of pathogens so as to reduce the probability of infection. Disgust also shows the source effects based on familiarity. However, these source effects have not been tested on the older population. Thus, we tested the source effects of emotional and behavioral reactions from the disgust toward older adults and the possible moderating effects of filial piety on disgust. In the first study, we employed the self-report method to test the source effects of emotional feelings of disgust amongst undergraduates. In the second study, we measured whether filial piety among community adults produced moderating effects of the disgust toward older adults. In the third study, we employed the shape discrimination task to test the source effects of behavioral avoidance to older adults among undergraduates. The first and third studies show stronger negative emotional/avoidance reactions towards unfamiliar older adults than familiar older adults, affirming the source effects of disgust towards older adults that we expected. However, we did not find moderating effects of filial piety associated with disgust. These findings can help us understand the evolutionary origin of disgust toward older adults, which is likely activated more intensely and quickly in response to unfamiliar individuals as compared with familiar individuals.

Health belief model and behavioural practice of urban poor towards COVID-19 in Nigeria

Poor adherence to promoting health behaviours is a significant challenge for prevention and management of infectious respiratory diseases. Non-pharmaceutical Interventions (NPIs) remain a proven behavioural practice for reducing the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) currently ravaging the world. Studies on Covid-19 have primarily focused on epidemiology, virology, and potential drug treatments to the neglect of behavioural practice of low-income settings. This study examines the extent health belief model predicts the behavior of 405 urban poor residents of Ogun State, which recorded the first index case in Nigeria, towards adoption Covid-19 NPIs. A cross-sectional study was conducted to find out the relationship between study participant characteristics, HBM constructs and unhealthy behavior. Study constructs were assessed on a four point Likert scale and were mean aggregated such that higher scores indicated stronger feelings about a construct. Findings shows that urban poor in the age group 30-40 years were more likely to feel susceptible to contracting Covid-19 (mean score: 2.59 and std. dev. 0.54), they also had a higher perception of the benefit of Covid-19 preventive behaviours than participants in other age groups (mean score: 2.95 and std. dev. 0.71). Also, the most prevalent unhealthy behaviour amongst urban poor residents was the indiscriminate use of facemasks as shown by almost half (47.6%) of participants who agreed that they use facemasks all the time even when alone. The study concludes that though urban poor residents feel threatened by Covid-19, nexus of factors such as low financial earnings, inadequate knowledge, and limited access to basic medical needs hamper the effective adoption of NPIs.

Investigation of the relationship between nursing students' disgust sensitivity and caring behaviours

AIM

This study aimed to investigate the disgust sensitivity of nursing students, the factors affecting this sensitivity, their caring behaviors and the relationships between these components.

BACKGROUND

Disgust sensitivity has been conceptualized as the degree of disgust felt in response to various stimuli. Nursing students often encounter recognized disgust triggers in clinical practice, such as feces, mucus, urine, foul-smelling wounds and contact with the dead. The nursing students' disgust sensitivity can affect the way they think and may affect their care behaviors.

DESIGN

The study used a descriptive cross-sectional design and was conducted with nursing students in a Turkish university nursing program (n = 577).

METHODS

The study data was collected through the Disgust Sensitivity Scale-Revised Form and the Caring Assessment Questionnaire.

RESULTS

Of the students in the study, 59.6% stated that they experienced disgust while providing care. A negative relationship was found between students' total scores from the Disgust Scale and the Caring Assessment Questionnaire (p < 0.01). The students' disgust sensitivity level was high and the higher the disgust sensitivity, the fewer caring behaviors they exhibited.

CONCLUSIONS

In light of these findings, it can be said that the caring behaviors of nursing students are negatively influenced by disgust sensitivity. Hence, nurse educators need to evaluate students' disgust sensitivity, help students to identify and address their disgust emotions, deal with disgust management strategies together and be aware of when students need support.

Pathogen disgust sensitivity protects against infection in a high pathogen environment

Disgust is hypothesized to be an evolved emotion that functions to regulate the avoidance of pathogen-related stimuli and behaviors. Individuals with higher pathogen disgust sensitivity (PDS) are predicted to be exposed to and thus infected by fewer pathogens, though no studies have tested this directly. Furthermore, PDS is hypothesized to be locally calibrated to the types of pathogens normally encountered and the fitness-related costs and benefits of infection and avoidance. Market integration (the degree of production for and consumption from market-based economies) influences the relative costs/benefits of pathogen exposure and avoidance through sanitation, hygiene, and lifestyle changes, and is thus predicted to affect PDS. Here, we examine the function of PDS in disease avoidance, its environmental calibration, and its socioecological variation by examining associations among PDS, market-related lifestyle factors, and measures of bacterial, viral, and macroparasitic infection at the individual, household, and community levels. Data were collected among 75 participants (ages 5 to 59 y) from 28 households in three Ecuadorian Shuar communities characterized by subsistence-based lifestyles and high pathogen burden, but experiencing rapid market integration. As predicted, we found strong negative associations between PDS and biomarkers of immune response to viral/bacterial infection, and weaker associations between PDS and measures of macroparasite infection, apparently mediated by market integration-related differences. We provide support for the previously untested hypothesis that PDS is negatively associated with infection, and document variation in PDS indicative of calibration to local socioeconomic conditions. More broadly, findings highlight the importance of evolved psychological mechanisms in human health outcomes.

Differential effects of progesterone on social recognition and the avoidance of pathogen threat by female mice

Although pathogen threat affects social and sexual responses across species, relatively little is known about the underlying neuroendocrine mechanisms. Progesterone has been speculated to be involved in the mediation of pathogen disgust in women, though with mixed experimental support. Here we considered the effects of acute progesterone on the disgust-like avoidance responses of female mice to pathogen threat. Estrous female mice discriminated and avoided the urinary and associated odors of males subclinically infected with the murine nematode parasite, Heligmosomoides polygyrus. These avoidance responses were not significantly affected by pre-treatment with progesterone. Likewise, brief (1 min) exposure to the odors of infected males attenuated the subsequent responses of females to the odors of the normally preferred unfamiliar males and enhanced their preferences for familiar males. Neither progesterone nor allopregnanolone, a central neurosteroid metabolite of progesterone, had any significant effects on the avoidance of unfamiliar males elicited by pre-exposure to a parasitized male. Progesterone and allopregnanolone, did, however, significantly attenuate the typical preferences of estrous females for unfamiliar uninfected males, suggestive of effects on social recognition. These findings with mice indicate that progesterone may have minimal effects on the responses to specific parasite threat and the expression of pathogen disgust but may influence more general social recognition and preferences.

Neural Basis of Increased Cognitive Control of Impulsivity During the Mid-Luteal Phase Relative to the Late Follicular Phase of the Menstrual Cycle

Hormonal changes across the menstrual cycle have been shown to influence reward-related motivation and impulsive behaviors. Here, with the aim of examining the neural mechanisms underlying cognitive control of impulsivity, we compared event-related monetary delay discounting task behavior and concurrent functional magnetic resonance imaging (fMRI) revealed brain activity as well as resting state (rs)-fMRI activity, between women in the mid-luteal phase (LP) and women in the late follicular phase (FP). The behavioral data were analyzed and related to neural activation data. In the delay discounting task, women in the late FP were more responsive to short-term rewards (i.e., showed a greater discount rate) than women in the mid-LP, while also showing greater activity in the dorsal striatum (DS). Discount rate (transformed k) correlated with functional connectivity between the DS and dorsal lateral prefrontal cortex (dlPFC), consistent with previous findings indicating that DS-dlPFC circuitry may regulate impulsivity. Our rs-fMRI data further showed that the right dlPFC was significantly more active in the mid-LP than in late FP, and this effect was sensitive to absolute and relative estradiol levels during the mid-LP. DS-dlPFC functional connectivity magnitude correlated negatively with psychometric impulsivity scores during the late FP, consistent with our behavioral data and further indicating that relative estradiol levels may play an important role in augmenting cognitive control. These findings provide new insight into the treatment of conditions characterized by hyper-impulsivity, such as obsessive compulsive disorder, Parkinson disease, and attention deficit hyperactivity disorder. In conclusion, our results suggest that cyclical gonadal hormones affect cognitive control of impulsive behavior in a periodic manner, possibility via DS-dlPFC circuitry.

Pharyngeal Detection of Staphylococcus aureus as a Possible Factor Related to Disgust Sensitivity in Humans

Disgust triggers behavioral avoidance of pathogen-carrying and fitness-reducing agents. However, because of the cost involved, disgust sensitivity should be flexible, varying as a function of an individual’s immunity. Asymptomatic colonization with Staphylococcus aureus often results from weakened immunity and is a potential source of subsequent infections. In this study, we tested if pharyngeal colonization with S. aureus, evaluated based on a single swab collection, is related to an individual’s disgust sensitivity, measured with the Three Domain Disgust Scale. Levels of immunomodulating hormones (cortisol and testosterone), general health, and body adiposity were controlled. Women (N = 95), compared to men (N = 137), displayed higher sexual disgust sensitivity, but the difference between individuals with S. aureus and without S. aureus was significant only in men, providing support for prophylactic hypothesis, explaining inter-individual differences in disgust sensitivity. Men (but not women) burdened with asymptomatic S. aureus presence in pharynx exhibit higher pathogen disgust (p = 0.04) compared to individuals in which S. aureus was not detected. The positive relationship between the presence of the pathogen and sexual disgust was close to the statistical significance level (p = 0.06), and S. aureus colonization was not related with moral disgust domain.

Disgust regulation between menstrual cycle phases: Differential effects of emotional suppression and reappraisal

BACKGROUND AND OBJECTIVE

Immunosuppression is characteristic of the luteal phase of the menstrual cycle and is accompanied by an adaptive disgust response to reduce contact with pathogens. However, research has not examined the effects of emotion regulation on disgust during the menstrual cycle. Accordingly, the present study examines the effect of suppression and reappraisal on disgust during the luteal and follicular phases of the menstrual cycle.

METHOD

Menstrual cycle phase was estimated in a sample of naturally cycling women (n = 73), and those in the follicular or luteal phase were assigned to suppress or reappraise disgust while watching a disgust-inducing video. Physiological arousal during the video and avoidance of disgust cues in a public restroom after the video were also assessed.

RESULTS

No differences were observed in self-reported disgust to the video between those who suppressed and those who reappraised in the luteal phase. However, women in the follicular phase who suppressed reported less disgust than those who reappraised. The emotion regulation strategies did not influence physiology during the video or avoidance after the video as a function of menstrual cycle phase.

LIMITATIONS

Hormone assay data was not collected to confirm menstrual cycle phase and a relatively small sample of naturally cycling women was used.

CONCLUSIONS

Suppression may be a more effective strategy than reappraisal for reducing verbal disgust in the follicular phase but not in the luteal phase. The implications of these findings for the treatment of disgust-based disorders among women are discussed.

It's not you, it's me - disgust sensitivity towards body odor in deaf and blind individuals

Disgust might be elicited by various sensory channels, including the sense of smell. It has been previously demonstrated that unpleasant odors emitted by an external source are more disgusting than those emitted by oneself (the source effect). As disgust's main purpose is to help organisms avoid potentially dangerous, contaminating objects, individuals with visual or hearing sensory impairment (thus, with an impeded ability to detect cues indicating pathogen threat) might have developed an increased levels of olfactory disgust sensitivity (modality compensation in disgust sensitivity). We set out to investigate disgust sensitivity in olfaction using the Body Odor Disgust Scale (BODS) on a large sample of 74 deaf and 98 blind participants, with comparison to control groups without sensory impairment (N = 199 in total). The results did not support the hypothesis of modality compensation in disgust sensitivity. Contrary to previous research, neither sex nor age influenced the outcomes. Evidence for the source effect was found. Acquired data are interpreted in the light of social desirability. The emphasis put on the olfaction by blind and deaf individuals is discussed.

The Role of Age and Gender in Perceived Vulnerability to Infectious Diseases

Background: The study of the immune system has been approached using two separate paths, the biological immune system and the behavioral immune system. Recently, Gangestad and Grebe proposed a unique integrated compensatory immune system, where both systems work together and one of them could compensate for the other when necessary. However, few studies have confirmed the existence of this integrated compensatory immune system. Our study represents an attempt to explore the existence of this unique immune system, investigating if the behavioral immune system variables increase when the biological immune system weakens with age. Material and Methods. The cross-sectional design study was made up of a final sample of 1108 participants (45.2% men and 54.2 women) aged 18-64 years. The younger group (18-21 years) was made up of students, whilst the older groups (22 to 64 years) were composed by their relatives and acquaintances, following the snow ball process. The participants completed the Perceived Vulnerability to Disease Questionnaire that assesses perceived infectability and germ aversion. Correlations, analyses of variance (ANOVAs), and independent group comparisons were performed. These analyses showed the relationships between the variables studied, the effects of age and gender in perceived infectability and germ aversion, and the differences that perceived infectability and germ aversion presented in different age-groups separated by gender. Results: A pattern emerged where germ aversion increases as both men and women get older, but perceived infectability decreases up to the age of 50, and then it increases in women from that age onward. Gender differences are only significant in younger participants, with women having higher scores than men in both variables. Conclusion: The results partially support the existence of a unique integrated compensatory biological/behavioral immune system.

Increased sensitivity to social exclusion during the luteal phase: Progesterone as resilience factor buffering against ostracism?

A woman's social behaviour reportedly varies across the menstrual cycle. In this study, we estimated changes in sensitivity to social exclusion across the menstrual cycle and scrutinized the related role of progesterone. Forty-nine naturally cycling women played a virtual ball-tossing game (Cyberball) to manipulate social inclusion. All participants underwent inclusion and exclusion conditions during the late follicular and the luteal phase. We assessed salivary progesterone concentrations at each cycle phase. After each Cyberball session we measured positive/negative mood using the Multidimensional Mood State Questionnaire (MDMQ). Multilevel analyses indicated that women showed worse mood following exclusion as compared to inclusion conditions (p = 0.014). Notably, this exclusion effect was more pronounced during the luteal phase than the late follicular phase (p = 0.029). As expected, progesterone concentrations were higher during the luteal phase as compared to the late follicular phase, but interestingly, progesterone concentrations were negatively associated with exclusion effects. When accounting for mediation via progesterone, direct cycle-phase related differences in social exclusion effects even increased as compared to the model without mediator. These findings suggest that progesterone may function as buffer against negative feelings that result from being socially excluded. The relevance of these findings for Premenstrual Dysphoric Disorder (PMDD) are discussed, and we conclude that social exclusion may represent an important research domain criterion (RDoC) of relevance for PMDD, with progesterone pointing to new potential pharmacological targets.

Hygienic personalities in wild grey mouse lemurs vary adaptively with sex

Detecting the risk of infection and minimizing parasite exposure represent the first lines of host defence against parasites. Individuals differ in the expression of these behavioural defences, but causes of such variation have received little empirical attention. We therefore experimentally investigated the effects of several individual and environmental factors on the expression level of faecal avoidance in the context of feeding, drinking, sleeping and defecating in a wild primate population. We found a strong sex bias in the expression level of anti-parasite behaviours of grey mouse lemurs (Microcebus murinus), with only females strongly avoiding contaminated food, water and nests, and exhibiting selective defecation. Our results further suggest that individuals adapted their protective behaviours according to variation in intrinsic and ecological factors that may influence the cost-benefit balance of behavioural defences. Overall, individuals exhibited high consistency of investment in protective behaviours across behavioural contexts and time, suggesting that grey mouse lemurs exhibit different hygienic personalities. Finally, the global hygienic score was negatively correlated with faecal-orally transmitted parasite richness, suggesting that variation in behavioural defence has fitness consequences. We suggest that integrating inter-individual variation in behavioural defences in epidemiological studies should improve our ability to model disease spread within populations.

Sex differences in the etiology of disgust sensitivity: A preliminary behavioral genetic analysis

Evidence suggests that Disgust Sensitivity (DS) is a personality trait that may confer risk for the development of some anxiety-related disorders. To examine the origins of this trait we administered the DS subscale of the Disgust Propensity and Sensitivity Scale-Revised to 90 monozygotic and 90 dizygotic twin pairs, of which 55% were women. The DS subscale consists of two dimensions; Somatic Disgust and Ruminative Disgust. Biometrical modeling techniques were used to estimate heritability of the DS dimensions by sex. For women, each dimension was influenced by a combination of genetic and environmental factors. More specifically, 40.1% of the variance in DS was observed to be due to additive genetic factors and the remaining variance due to non-shared environment. Correlations among DS dimensions for women could be explained by genetic and environmental factors influencing the two dimensions. For men, the two dimensions were influenced by environmental but not genetic factors. These findings suggest that the etiology of DS is complex and arises as a function of dimension-specific and non-specific etiologic factors that vary as a function of sex. The implication of these findings for the sex differences in the etiology of some anxiety-related disorders are discussed.

Phase of the menstrual cycle affects engagement of attention with emotional images

Changes that occur during the menstrual cycle affect various aspects of behavior, cognition, and emotion. Here, we focused on potential differences between early follicular and midluteal phases in the way women process images of behaviorally relevant content categories: children, threat, disgust, erotic scenes, low- and high-calorie food. Using eye-tracking, we examined women's engagement of attention in the key region of each image in a free-viewing condition. Specifically, we tested how quickly attention was attracted to these regions and for how long it was held there. Participants took part in two experimental sessions, one in the early follicular and one in the midluteal phase. The results showed that in the midluteal phase attention was attracted to the key region earlier than in the early follicular phase: the first fixation more often fell within the key region and there were fewer fixations preceding it. While the effect of the phase in terms of the capture of attention did not depend on the image category, the effect regarding the hold of attention was category-specific, concerning the disgust category only. Specifically, in the midluteal phase the duration of the exploration of the key region between reaching it for the first time and first exiting it was shorter, which might be due to heightened sensitivity to disgusting stimuli in this period. Overall, our results indicate the occurrence of changes in attentional processing of emotional scenes related to the menstrual cycle, which seem to differ depending on the aspect of attention deployment: in the midluteal phase the effect of enhancing orienting was general and concerned any important visual information, whereas the effect of the shortened hold of attention appeared to be limited to specific content.

Pathogen disgust sensitivity changes according to the perceived harshness of the environment

Much research has explored behaviours that are linked with disgust sensitivity. Few studies, however, have been devoted to understanding how fixed or variable disgust sensitivity is. We therefore aimed to examine whether disgust sensitivity can change with the environment by repeatedly testing students whose environment was not changing as well as student cadets undergoing intensive training at an army camp. We found that an increase in the perceived harshness of the environment was associated with a decrease in pathogen disgust sensitivity. Our results support the idea that disgust sensitivity is malleable depending on the environment. More specifically, we propose that in a harsh environment, where survival may be more difficult, pathogen disgust sensitivity may decrease to allow the consumption of available resources.

Consumption, contact and copulation: how pathogens have shaped human psychological adaptations

Disgust is an emotion intimately linked to pathogen avoidance. Building on prior work, we suggest disgust is an output of programmes that evolved to address three separate adaptive problems: what to eat, what to touch and with whom to have sex. We briefly discuss the architecture of these programmes, specifying their perceptual inputs and the contextual factors that enable them to generate adaptive and flexible behaviour. We propose that our sense of disgust is the result of these programmes and occurs when information-processing circuitries assess low expected values of consumption, low expected values of contact or low expected sexual values. This conception of disgust differs from prior models in that it dissects pathogen-related selection pressures into adaptive problems related to consumption and contact rather than assuming just one pathogen disgust system, and it excludes moral disgust from the domain of disgust proper. Instead, we illustrate how low expected values of consumption and contact as well as low expected sexual values can be used by our moral psychology to provide multiple causal links between disgust and morality.This article is part of the Theo Murphy meeting issue 'Evolution of pathogen and parasite avoidance behaviours'.

The source effect as a natural function of disgust in interpersonal context and its impairment in mental disorders

Disgust affects interpersonal relationships and regulates hygienic, sexual and distance behaviour. Its intensity in the interpersonal context depends on the character of the relationship. Strangers normally evoke more disgust than intimates (known as the source effect). General disgust sensitivity is increased in various mental diseases. It is unclear how disgust in the interpersonal context is affected and whether the source effect is preserved. 460 inpatients with mental disorders and 463 healthy subjects answered a newly developed Questionnaire (DIRQ) that covers disgust in the interpersonal context on content categories (hygiene, physical proximity, sexuality) and on source categories (self, partner, parent, stranger). Mental disorders were diagnosed with structured interviews. Healthy controls exhibited a pronounced source effect, with strangers evoking more disgust than intimates. In patients, this source effect was reduced (Cohen's d = 0.3), especially for sexual disgust, while general disgust sensitivity was increased (d = 0.5). High disgust in patients was best predicted by a history of sexual abuse and by the presence of post-traumatic stress disorder. In conclusion, mentally impaired patients show increased and trauma-associated disgust sensitivity. Their downregulation of sexual disgust in intimate relationships is hindered, which may have a boundary protective function but might also fuel difficulties engaging in relationships or intimacy.

Opposition to Inbreeding Between Close Kin Reflects Inclusive Fitness Costs

Due to the intense selection pressure against inbreeding, humans are expected to possess psychological adaptations that regulate mate choice and avoid inbreeding. From a gene's-eye perspective, there is little difference in the evolutionary costs between situations where an individual him/herself is participating in inbreeding and inbreeding among other close relatives. The difference is merely quantitative, as fitness can be compromised via both routes. The question is whether humans are sensitive to the direct as well as indirect costs of inbreeding. Using responses from a large population-based sample (27,364 responses from 2,353 participants), we found that human motivations to avoid inbreeding closely track the theoretical costs of inbreeding as predicted by inclusive fitness theory. Participants were asked to select in a forced choice paradigm, which of two acts of inbreeding with actual family members they would want to avoid most. We found that the estimated fitness costs explained 83.6% of participant choices. Importantly, fitness costs explained choices also when the self was not involved. We conclude that humans intuit the indirect fitness costs of mating decisions made by close family members and that psychological inbreeding avoidance mechanisms extend beyond self-regulation.

Sensitivity to Deviance and to Dissimilarity: Basic Cognitive Processes Under Activation of the Behavioral Immune System

Throughout evolutionary history, pathogens have imposed strong selection pressures on humans. To minimize humans' exposure to pathogens, a behavioral immune system that promotes the detection and avoidance of disease-connoting cues has evolved. Although most pathogens cannot be discerned by our sensory organs, they produce discernable changes in their environment. As a result, a common denominator of many disease-connoting cues is morphological deviance-figurative disparity from what is normal, visual dissimilarity to the prototype stored in memory. Drawing on an evolutionary rationale, we examine the hypothesis that activation of the behavioral immune system renders people more sensitive to morphological deviance and more prone to perceive dissimilarities between stimuli. In Study 1 ( N = 343), participants who scored higher on disgust sensitivity demonstrated greater differentiation between normal and disfigured faces, reflecting greater sensitivity to morphological deviance in the bodily domain. In Study 2 ( N = 109), participants who were primed with pathogen threat demonstrated greater differentiation between perfect and imperfect geometrical shapes, reflecting greater sensitivity to morphological deviance even in stimuli that have nothing to do with health or disease. In Study 3 ( N = 621), participants who scored higher on disgust sensitivity perceived pairs of neutral pictures as less similar (i.e., more dissimilar) to each other. Literature on the relations to social deviance and implications for social perception and for social behavior is discussed.

Facial emotion recognition in violent men

The goal of this study was to explore the ability of violent men to recognise facial affect. In contrast to traditional approaches to this research question, we took the effects of the models' sex and different types of violent behaviour into consideration. Data obtained from 71 violent men revealed that they recognised facial expressions of fear (p = .019) and disgust (p = .013) more accurately when displayed by female than male models. The opposite was found for angry faces (p = .006), while the models' sex did not affect the recognition of sad, happy and surprised facial expressions or neutral faces. Furthermore, sexual coercion perpetrators were more accurate than other violent men in the recognition of female facial disgust (p = .006). These results are discussed in the context of social learning theory, and the hypothesis that female facial expressions of disgust could be subtle cues to their sexual infidelity that motivate sexual coercion in some men.

The "ick" Factor Matters: Disgust Prospectively Predicts Avoidance in Chemotherapy Patients

BACKGROUND

Chemotherapy can be physically and psychologically demanding. Avoidance and withdrawal are common among patients coping with these demands.

PURPOSE

This report compares established emotional predictors of avoidance during chemotherapy (embarrassment; distress) with an emotion (disgust) that has been unstudied in this context.

METHODS

This report outlines secondary analyses of an RCT where 68 cancer patients undergoing chemotherapy were randomized to mindfulness or relaxation interventions. Self-reported baseline disgust (DS-R), embarrassment (SES-SF), and distress (Distress Thermometer) were used to prospectively predict multiple classes of avoidance post-intervention and at 3 months follow-up. Measures assessed social avoidance, cognitive and emotional avoidance (IES Avoidance), as well as information seeking and treatment adherence (General Adherence Scale).

RESULTS

Repeated-measures ANOVAs evaluated possible longitudinal changes in disgust and forward entry regression models contrasted the ability of the affective variables to predict avoidance. Although disgust did not change over time or vary between groups, greater disgust predicted greater social, cognitive, and emotional avoidance, as well as greater information seeking. Social avoidance was predicted by trait embarrassment and distress predicted non-adherence.

CONCLUSIONS

This report represents the first investigation of disgust's ability to prospectively predict avoidance in people undergoing chemotherapy. Compared to embarrassment and distress, disgust was a more consistent predictor across avoidance domains and its predictive ability was evident across a longer period of time. Findings highlight disgust's role as an indicator of likely avoidance in this health context. Early identification of cancer patients at risk of deleterious avoidance may enable timely interventions and has important clinical implications (ACTRN12613000238774).

Evitação e proibição do incesto: fatores psicobiológicos e culturais

Resumo Embora historicamente a regulação proibitiva do incesto seja considerada um fenômeno cultural quase universal que não é influenciado por fatores psicobiológicos relativos à história evolutiva da espécie humana, evidências recentes têm questionado essa visão tradicional e defendido que a evitação e a proibição do incesto são influenciadas biológica e cognitivamente com a cultura. Este artigo objetiva desenvolver uma discussão teórica acerca da inibição e proibição do incesto, enfatizando os mecanismos evolutivos subjacentes a esses fenômenos. Argumenta-se a existência de mecanismos endógenos que evoluíram porque inibem a atividade sexual entre parentes próximos e que formam a base para regular socialmente a proibição do incesto (mecanismo exógeno). Destaca-se o efeito Westermarck, no qual a proximidade de pessoas que vivem juntas desde a infância provoca uma aversão ao intercurso sexual entre elas. A ausência de propensão ao incesto e sua proibição institucional constituem uma complexa integração entre fatores psicobiológicos e culturais.

Moral and Sexual Disgust Suppress Sexual Risk Behaviors among Men Who Have Sex with Men in China

Increasingly more men who have sex with men (MSM) are engaging in sexual risk taking in China in recent years. Given the high rates of HIV infection among MSM in China, it is urgent that we understand the factors that influence MSM's practice of sexual risk taking. Disgust sensitivity, which elicits a behavioral avoidance response, has the potential to influence risky sexual behavior. The present study examined the relationship between disgust sensitivity and sexual risk behavior among MSM in China. Men (n = 584) who reported having anal intercourse in the previous 6 months were recruited from the Internet. Two indicators of sexual risk behaviors were measured: condom use and the number of sex partners. The results indicated that moral disgust was positively associated with condom use, with MSM who had higher moral disgust being more likely to use condoms than others did. Sexual disgust was positively associated with the number of sex partners, with MSM who had higher sexual disgust having fewer male sex partners than others did. Sexual and moral disgust sensitivity significantly predicted HIV testing. Our study verified that sexual and moral disgust suppressed sexual risk behaviors and promoted HIV testing. Moral and sexual education should be incorporated in future strategies for HIV prevention and encouragement of safe sex behaviors among MSM in China.

Strangers With Benefits: Attraction to Outgroup Men Increases as Fertility Increases Across the Menstrual Cycle

Research typically reveals that outgroups are regarded with disinterest at best and hatred and enmity at worst. Working from an evolutionary framework, we identify a unique pattern of outgroup attraction. The small-group lifestyle of pre-human ancestors plausibly limited access to genetically diverse mates. Ancestral females may have solved the inbreeding dilemma while balancing parental investment pressures by mating with outgroup males either via converting to an outgroup or cuckolding the ingroup. A vestige of those mating strategies might manifest in human women as a cyclic pattern of attraction across the menstrual cycle, such that attraction to outgroup men increases as fertility increases across the cycle. Two studies, one using a longitudinal method and the other an experimental method, evidenced the hypothesized linear relationship between attraction to outgroup men and fertility in naturally cycling women.

Differential disgust responding in people with cancer and implications for psychological wellbeing

OBJECTIVES

Evidence suggests that disgust responses, known to negatively affect psychological wellbeing, may differ in people with cancer. We performed the first quantitative investigation of three discrete types of disgust trait - disgust propensity, sensitivity and self-directed disgust - in people diagnosed with a broad range of cancers (versus cancer-free controls), and explored their associations with psychological wellbeing.

DESIGN

In a cross-sectional survey design, 107 participants with heterogeneous cancer diagnoses, recruited from cancer charities and support groups, were matched with cancer-free controls by age and gender.

OUTCOME MEASURES

Measures of the three disgust traits were taken alongside measures of anxiety and depression.

RESULTS

Disgust sensitivity and physical self-disgust were significantly higher in the cancer than control sample, while disgust propensity and behavioural self-disgust were lower. The disgust traits had a different pattern of associations to psychological wellbeing across the two groups, with disgust sensitivity predicting depressive symptoms to a significantly greater extent in the cancer than control group.

CONCLUSIONS

People with cancer differ from matched controls in their disgust responses and these responses have significant predictive relationships with aspects of their psychological wellbeing. The results suggest that emotion-based interventions may be useful for improving psychological wellbeing in people with cancer.