The behavioural immune system and pandemic psychology: the evolved psychology of disease-avoidance and its implications for attitudes, behaviour, and public health during epidemic outbreaks

Looking beyond vaccines: Cultural tightness-looseness moderates the relationship between immunization coverage and disease prevention vigilance

Advancements in vaccination technologies mitigate disease transmission risks but may inadvertently suppress the behavioral immune system, an evolved disease avoidance mechanism. Applying behavioral immune system theory and utilizing robust big data analytics, we examined associations between rising vaccination coverage and government policies, public mobility, and online information seeking regarding disease precautions. We tested whether cultural tightness-looseness moderates the relationship between mass immunization and disease prevention vigilance. Comprehensive time series analyses were conducted using American data (Study 1) and international data (Study 2), employing transfer function modeling, cross-correlation function analysis, and meta-regression analysis. Across both the US and global analyses, as vaccination rates rose over time, government COVID-19 restrictions significantly relaxed, community mobility increased, and online searches for prevention information declined. The relationship between higher vaccination rates and lower disease prevention vigilance was stronger in culturally looser contexts. Results provide initial evidence that mass immunization may be associated with attenuated sensitivity and enhanced flexibility of disease avoidance psychology and actions. However, cultural tightness-looseness significantly moderates this relationship, with tighter cultures displaying sustained vigilance amidst immunization upticks. These findings offer valuable perspectives to inform nuanced policymaking and public health strategies that balance prudent precautions against undue alarm when expanding vaccine coverage worldwide.

Collective pronouns, collective health actions: Predicting pandemic precautionary measures through online first-person plural pronoun usage across U.S. states

The COVID-19 pandemic has underscored the role of group identification in shaping collective health behaviors. Using the novel Pronoun-Influenced Collective Health Model - an integrated framework combining elements from health and social psychology theories - we investigated the relationship between online first-person plural pronoun usage and adherence to COVID-19 preventive measures across the United States. Analyzing weekly Google Trends data on English (Study 1) and Spanish (Study 2) first-person pronoun searches, alongside data on adherence to pandemic precautionary measures from early 2020 to late 2022, we found significant positive associations between relative first-person plural pronoun search volumes and adherence to social distancing, stay-at-home orders, vaccination rates, and proactive disease prevention information seeking. These associations remained robust after adjusting for potential confounding factors. A mini meta-analysis (Study 3) confirmed the consistency of our findings, revealing no significant moderation effects by language context or ecological-socio-cultural factors, suggesting broad generalizability. The implications of this research highlight the potential for tracking online collective language as a valuable indicator of and proxy for societal-level health engagement during crises. This novel digital linguistics approach, synergistically combining applied health and social psychology with big data from digital platforms such as Google, offers powerful tools for monitoring collective health actions across linguistic and cultural boundaries during large-scale health crises.

Visual attention is not attuned to non-human animal targets' pathogenicity: an evolutionary mismatch perspective

A considerable amount of research has revealed that there exists an evolutionary mismatch between ancestral environments and conditions following the rise of agriculture regarding the contact between humans and animal reservoirs of infectious diseases. Based on this evolutionary mismatch framework, we examined whether visual attention exhibits adaptive attunement toward animal targets' pathogenicity. Consistent with our predictions, faces bearing heuristic infection cues held attention to a greater extent than did animal vectors of zoonotic infectious diseases. Moreover, the results indicated that attention showed a specialized vigilance toward processing facial cues connoting the presence of infectious diseases, whereas it was allocated comparably between animal disease vectors and disease-irrelevant animals. On the other hand, the pathogen salience manipulation employed to amplify the participants' contextual-level anti-pathogen motives did not moderate the selective allocation of attentional resources. The fact that visual attention seems poorly equipped to detect and encode animals' zoonotic transmission risk supports the idea that our evolved disease avoidance mechanisms might have limited effectiveness in combating global outbreaks originating from zoonotic emerging infectious diseases.

Taking Stock and Looking Forward to the Future of Pathogen Politics in Light of New Insights and Recommendations: COVID-19 Threat Was Meaningfully Associated With Support for Liberal Policies in the United States

Infectious disease outbreaks are expected to predict support for conservative policies. However, earlier studies (January-June, 2020) reached conflicting findings regarding the association between COVID-19 threat and policy preferences in the United States. We revisit this issue by analyzing five nationally representative surveys conducted during the relatively severe periods of the pandemic (August 2020-December, 2020; total N = 82,753). Using Bayesian inference, we find strong evidence that subjective (e.g., fear of infection and pandemic outrage) but not objective (e.g., local cases and deaths) threat predicted support for liberal policies (e.g., immigration and universal health care). Meta-analyses revealed that the estimates depend on the type of subjective (.05 ≥ r ≤ .60) or objective (.00 ≥ r ≤ .14) COVID-19 threat. We propose an emotion-mediated dual-process model of pathogen management suggesting that infectious disease outbreaks activate both avoidance and caregiving motives that translate, respectively, into support for right-wing and left-wing policies.

Homo temporus: Seasonal Cycles as a Fundamental Source of Variation in Human Psychology

Many animal species exhibit seasonal changes in their physiology and behavior. Yet despite ample evidence that humans are also responsive to seasons, the impact of seasonal changes on human psychology is underappreciated relative to other sources of variation (e.g., personality, culture, development). This is unfortunate because seasonal variation has potentially profound conceptual, empirical, methodological, and practical implications. Here, we encourage a more systematic and comprehensive collective effort to document and understand the many ways in which seasons influence human psychology. We provide an illustrative summary of empirical evidence showing that seasons impact a wide range of affective, cognitive, and behavioral phenomena. We then articulate a conceptual framework that outlines a set of causal mechanisms through which seasons can influence human psychology-mechanisms that reflect seasonal changes not only in meteorological variables but also in ecological and sociocultural variables. This framework may be useful for integrating many different seasonal effects that have already been empirically documented and for generating new hypotheses about additional seasonal effects that have not yet received empirical attention. The article closes with a section that provides practical suggestions to facilitate greater appreciation for, and systematic study of, seasons as a fundamental source of variation in human psychology.

Pornography and Sociosexual Attitudes and Behaviors in a Nationally Representative Survey: Potential Pandemic and Method Effects

Due to the COVID-19 pandemic, The General Social Survey (GSS) switched from an in-person interview to a self-administered online survey for its most recent data collection. This modality switch makes it possible to compare sociosexual data gathered using the GSS's last in-person survey (2018) to its first-ever self-administered online survey (2021), an oft suggested format for reducing social desirability bias. This study compared sociosexual data collected in the 2018 GSS to the 2021 GSS, with a primary focus on pornography use. Results suggested that among men neither the direction nor the magnitude of the association between pornography use and more nontraditional sociosexual attitudes and behaviors are affected by whether surveys are conducted in-person or online; that among women the magnitude of the positive association between pornography use and certain nontraditional sexual behaviors could be attenuated by in-person interviews; a pandemic period increase in pornography use among both men and women; a pandemic period decrease in men's nonrelational sexual behavior; and that men's and women's reporting of certain nontraditional sexual attitudes may be reduced by in-person interviews. It is important to emphasize that alternative explanations for 2018-2021 change are possible. The goal of the present study was to promote interpretive dialogue rather than definitive answers.

The Onset of the COVID-19 Pandemic Made People Feel Threatened, but Had a Limited Impact on Political Attitudes in the United States

We investigated if the COVID-19 pandemic's onset caused changes in political attitudes. Influential theories predict that the pandemic's onset will cause people to adopt more conservative attitudes, more culturally conservative attitudes, or more extreme attitudes. We comprehensively tested the external validity of these predictions by estimating the causal effect of the pandemic's onset on 84 political attitudes and eight perceived threats using fine-grained repeated cross-sectional data (Study 1, N = 232,684) and panel data (Study 2, N = 552) collected in the United States. Although the pandemic's onset caused feelings of threat, the onset only caused limited attitude change (six conservative shifts, four extremity shifts, 12 liberal shifts, 62 no change). Prominent theories of threat and politics did not make accurate predictions for this major societal threat. Our results highlight the necessity of testing psychological theories' predictive powers in real-life circumstances.

Coronavirus-Related Searches on the Internet Predict COVID-19 Vaccination Rates in the Real World: A Behavioral Immune System Perspective

According to the smoke detector and functional flexibility principles of human behavioral immune system (BIS), the exposure to COVID-19 cues could motivate vaccine uptake. Using the tool of Google Trends, we tested that coronavirus-related searches-which assessed natural exposure to COVID-19 cues-would positively predict actual vaccination rates. As expected, coronavirus-related searches positively and significantly predicted vaccination rates in the United States (Study 1a) and across the globe (Study 2a) after accounting for a range of covariates. The stationary time series analyses with covariates and autocorrelation structure of the dependent variable confirmed that more coronavirus-related searches compared with last week indicated increases in vaccination rates compared with last week in the United States (Study 1b) and across the globe (Study 2b). With real-time web search data, psychological scientists could test their research questions in real-life settings and at a large scale to expand the ecological validity and generalizability of the findings.

People with High Perceived Infectability Are More Likely to Spread Rumors in the Context of COVID-19: A Behavioral Immune System Perspective

Since the outbreak of COVID-19, many studies have explored the influencing factors of rumor spreading, such as anxiety, risk perception and information source credibility, but few studies have focused on the impact of individual differences. Based on the theory of behavioral immune systems, we investigated the impact of perceived infectability on rumor spreading and the mediating role of rumor trust in the context of COVID-19. Two studies were investigated using the scale and recall-report task of rumor spreading. The results show that perceived infectability was a significant positive predictor of rumor spreading. However, the impact of perceived infectability on rumor spreading was not direct, and it mainly indirectly affected rumor spreading through the mediating role of rumor trust. Overall, the findings suggest that individuals with high perceived infectability are more likely to believe rumors and then spread rumors during the epidemic. This study advances the literature on rumor spreading and behavioral immune systems and provides practical implications to anti-rumor campaigns.

Responses to COVID-19 Threats: an Evolutionary Psychological Analysis

Responses to COVID-19 public health interventions have been lukewarm. For example, only 64% of the US population has received at least two vaccinations. Because most public health interventions require people to behave in ways that are evolutionarily novel, evolutionary psychological theory and research on mismatch theory, the behavioral immune system, and individual differences can help us gain a better understanding of how people respond to public health information. Primary sources of threat information during the pandemic (particularly in early phases) were geographic differences in morbidity and mortality statistics. We argue that people are unlikely to respond to this type of evolutionarily novel information, particularly under conditions of high uncertainty. However, because individual differences affect threat perceptions, some individual differences will be associated with threat responses. We conducted two studies (during Phase 1 and 2 years later), using data from primarily public sources. We found that state-level COVID-19 morbidity and mortality rates had no relationship with mental health symptoms (an early indicator of how people were responding to the pandemic), suggesting that people-in general-were not attending to this type of information. This result is consistent with the evolutionary psychological explanation that statistical information is likely to have a weak effect on the behavioral immune system. We also found that individual differences (neuroticism, IQ, age, and political ideology) affected how people responded to COVID-19 threats, supporting a niche-picking explanation. We conclude with suggestions for future research and suggestions for improving interventions and promoting greater compliance.

Reductions in perceived COVID-19 threat amid UK's mass public vaccination programme coincide with reductions in outgroup avoidance (but not prejudice)

It has long been proposed that perceptions of threat contribute to greater outgroup negativity. Much of the existing evidence on the threat-prejudice association in the real world, however, is cross-sectional in nature. Such designs do not adequately capture individual-level changes in constructs, and how changes in constructs relate to changes in other theoretically relevant constructs. The current research exploited the unique opportunity afforded by the mass COVID-19 vaccination programme in the United Kingdom to explore whether reductions in pathogen threat coincide with reductions in outgroup prejudice and avoidance. A two-wave longitudinal study (N1  = 912, N2  = 738) measured British adult's perceptions of COVID-19 threat and anti-immigrant bias before and during mass vaccine rollout in the United Kingdom. Tests of latent change models demonstrated that perceived COVID-19 threat significantly declined as the vaccine programme progressed, as did measures of outgroup avoidance tendencies, but not prejudiced attitudes. Critically, change in threat was systematically correlated with change in outgroup avoidance: those with greater reductions in perceived COVID-19 threat were, on average, those with greater reductions in outgroup avoidance. Findings provide important and novel insights into the implications of disease protection strategies for intergroup relations during an actual pandemic context, as it unfolds over time.

Individual and collective protective responses during the early phase of the COVID-19 pandemic in 10 different countries: Results from the EUCLID online survey

BACKGROUND

In times of unprecedented infectious disease threats, it is essential to understand how to increase individual protective behaviors and support for collective measures. The present study therefore examines factors associated with individual and collective pathways.

METHODS

Data was collected through an online survey from 4483 participants (70.8% female, M = 41.2 years) across 10 countries from April 15, 2020 to June 2, 2020 as part of the "EUCLID" project (https://euclid.dbvis.de). Structural equation modeling was used to examine individual and collective pathways across and within countries.

RESULTS

Overall, the adoption of individual protective behaviors and support for collective measures were high. Risk perception on the individual level and perceived effectiveness at the collective level were positively associated with both individual protective behaviors and support for collective measures. Furthermore, the model explained considerable variance in individual (40.7%) and collective protective behaviors (40.8%) and was largely replicated across countries.

CONCLUSIONS

The study extends previous research by demonstrating that individual risk perception and perceived effectiveness of collective measures jointly affect individual protective health behaviors and support for collective measures. These findings highlight the need to jointly consider a variety of behavioral actions against infectious disease threats, acknowledging interactions between individual and collective pathways.

Heightened religiosity proactively and reactively responds to the COVID-19 pandemic across the globe: Novel insights from the parasite-stress theory of sociality and the behavioral immune system theory

According to the parasite-stress theory of sociality and the behavioral immune system theory, heightened religiosity serves an anti-pathogen function by promoting in-group assortative sociality. Thus, highly religious countries/territories could have better control of the COVID-19 (proactively avoids disease-threat), and heightened COVID-19 threat could increase religiosity (reactively responds to disease-threat). As expected, country-level religiosity (religion-related online searches (Allah, Buddhism, Jesus, etc.) and number of total religions/ethnoreligions) negatively and significantly predicted COVID-19 severity (a composite index of COVID-19 susceptibility, reproductive rate, morbidity, and mortality rates) (Study 1a), after accounting for covariates (e.g., socioeconomic factors, ecological factors, collectivism index, cultural tightness-looseness index, COVID-19 policy response, test-to-case ratio). Moreover, multilevel analysis accounting for daily- (e.g., time-trend effect, season) and macro-level (same as in Study 1a) covariates showed that country-level religious searches, compared with the number of total religions/ethnoreligions, were more robust in negatively and significantly predicting daily-level COVID-19 severity during early pandemic stages (Study 1b). At weekly level, perceived coronavirus threat measured with coronavirus-related searches (corona, covid, covid-19, etc.), compared with actual COVID-19 threat measured with epidemiological data, showed larger effects in positively predicting religious searches (Study 2), after accounting for weekly- (e.g., autocorrelation, time-trend effect, season, religious holidays, major-illness-related searches) and macro-level (e.g., Christian-majority country/territory and all country-level variables in Study 1) covariates. Accordingly, heightened religiosity could proactively and reactively respond to the COVID-19 pandemic across the globe.

Pandemic threat and authoritarian attitudes in Europe: An empirical analysis of the exposure to COVID-19

While analysis of the impact of threatening events has moved from bit player to center stage in political science in recent decades, the phenomenon of pandemic threat is widely neglected in terms of a systematic research agenda. Tying together insights from the behavioral immune system hypothesis and standard political science models of emotional processing, we evaluate whether exposure to the COVID-19 pandemic threat is related to authoritarian attitudes and which emotions do the work. Using 12 samples with over 12,000 respondents from six European countries at two time points (2020 and 2021), we argue that pandemic threats can generate disgust, anger, and fear. Our analyses indicate that exposure to the COVID-19 pandemic threat particularly activates fear, which in turn is linked to authoritarian attitudes.

Heterogeneous adaptive behavioral responses may increase epidemic burden

Non-pharmaceutical interventions (NPIs) constitute the front-line responses against epidemics. Yet, the interdependence of control measures and individual microeconomics, beliefs, perceptions and health incentives, is not well understood. Epidemics constitute complex adaptive systems where individual behavioral decisions drive and are driven by, among other things, the risk of infection. To study the impact of heterogeneous behavioral responses on the epidemic burden, we formulate a two risk-groups mathematical model that incorporates individual behavioral decisions driven by risk perceptions. Our results show a trade-off between the efforts to avoid infection by the risk-evader population, and the proportion of risk-taker individuals with relaxed infection risk perceptions. We show that, in a structured population, privately computed optimal behavioral responses may lead to an increase in the final size of the epidemic, when compared to the homogeneous behavior scenario. Moreover, we find that uncertain information on the individuals' true health state may lead to worse epidemic outcomes, ultimately depending on the population's risk-group composition. Finally, we find there is a set of specific optimal planning horizons minimizing the final epidemic size, which depend on the population structure.