The evolution of personality variation in humans and other animals

To enhance or not to enhance: A debate about cognitive enhancement from a psychological and neuroscientific perspective

The enhancement of humans' core cognitive abilities-such as intelligence-is a frequently debated topic in scientific and public discourse. Different enhancement methods such as cognitive trainings, smart drugs, and brain stimulation techniques have been proposed and tested to enhance human's cognition. In this narrative review, we summarize the main psychological and neuroscientific findings regarding those cognitive enhancement methods. We thereby distinguish passive (e.g., smart drugs) and active enhancement methods (e.g., working memory training)-which require different levels of agency. While for both forms of enhancement there is no (or only little) empirical evidence on their effectiveness to improve overall cognitive abilities, passive methods entail severe risks. Thus, we criticize promoting an overly optimistic view on especially passive enhancement. Furthermore, we highlight which individuals might be willing to enhance themselves, related motivational aspects of cognitive enhancement, and ethical considerations thereof. To raise awareness for the (in)effectiveness and risks of passive and active enhancement, we propose a category framework that distinguishes cognitive enhancement from clinical methods to treat disorders or diagnosed deficits and introduces important dimensions thereof. Finally, we present open questions for psychological and neuroscientific research which should become part of enhancement debates. Taken together, our narrative review provides a broad overview and critical assessment of enhancement-related topics such as effectiveness and risks of enhancement methods, motivational aspects to apply enhancement, and societal implications of cognitive enhancement.

The genetic underpinnings of right-wing authoritarianism and social dominance orientation explain political attitudes beyond Big Five personality

OBJECTIVE

Political attitudes are predicted by the key ideological variables of right-wing authoritarianism (RWA) and social dominance orientation (SDO), as well as some of the Big Five personality traits. Past research indicates that personality and ideological traits are correlated for genetic reasons. A question that has yet to be tested concerns whether the genetic variation underlying the ideological traits of RWA and SDO has distinct contributions to political attitudes, or if genetic variation in political attitudes is subsumed under the genetic variation underlying standard Big Five personality traits.

METHOD

We use data from a sample of 1987 Norwegian twins to assess the genetic and environmental relationships between the Big Five personality traits, RWA, SDO, and their separate contributions to political policy attitudes.

RESULTS

RWA and SDO exhibit very high genetic correlation (r = 0.78) with each other and some genetic overlap with the personality traits of openness and agreeableness. Importantly, they share a larger genetic substrate with political attitudes (e.g., deporting an ethnic minority) than do Big Five personality traits, a relationship that persists even when controlling for the genetic foundations underlying personality traits.

CONCLUSION

Our results suggest that the genetic foundations of ideological traits and political attitudes are largely non-overlapping with the genetic foundations of Big Five personality traits.

Being facially expressive is socially advantageous

Individuals vary in how they move their faces in everyday social interactions. In a first large-scale study, we measured variation in dynamic facial behaviour during social interaction and examined dyadic outcomes and impression formation. In Study 1, we recorded semi-structured video calls with 52 participants interacting with a confederate across various everyday contexts. Video clips were rated by 176 independent participants. In Study 2, we examined video calls of 1315 participants engaging in unstructured video-call interactions. Facial expressivity indices were extracted using automated Facial Action Coding Scheme analysis and measures of personality and partner impressions were obtained by self-report. Facial expressivity varied considerably across participants, but little across contexts, social partners or time. In Study 1, more facially expressive participants were more well-liked, agreeable, and successful at negotiating (if also more agreeable). Participants who were more facially competent, readable, and perceived as readable were also more well-liked. In Study 2, we replicated the findings that facial expressivity was associated with agreeableness and liking by their social partner, and additionally found it to be associated with extraversion and neuroticism. Findings suggest that facial behaviour is a stable individual difference that proffers social advantages, pointing towards an affiliative, adaptive function.

An Evolutionary Perspective on the DSM-5 Alternative Model for Personality Disorders

Recent work has nested the Alternative Model for Personality Disorders (AMPD) within several theoretical paradigms of personality and clinical psychology (e.g., multivariate, psychodynamic). This has both spurred on additional research and aided in practical application. Connecting the model to other theoretical heuristics may lead to further advances. One candidate for such a theory is that of evolutionary psychology, which attempts to provide explanations of human behavior (including personality traits) rooted in adaptation. In this article, we review and integrate the theoretical and empirical literature on the AMPD and evolutionary psychology, providing a synthesis of the two models in the hope of furthering the research and application of both.

The genetics of niche-specific behavioral tendencies in an adaptive radiation of cichlid fishes

Behavior is critical for animal survival and reproduction, and possibly for diversification and evolutionary radiation. However, the genetics behind adaptive variation in behavior are poorly understood. In this work, we examined a fundamental and widespread behavioral trait, exploratory behavior, in one of the largest adaptive radiations on Earth, the cichlid fishes of Lake Tanganyika. By integrating quantitative behavioral data from 57 cichlid species (702 wild-caught individuals) with high-resolution ecomorphological and genomic information, we show that exploratory behavior is linked to macrohabitat niche adaptations in Tanganyikan cichlids. Furthermore, we uncovered a correlation between the genotypes at a single-nucleotide polymorphism upstream of the AMPA glutamate-receptor regulatory gene cacng5b and variation in exploratory tendency. We validated this association using behavioral predictions with a neural network approach and CRISPR-Cas9 genome editing.

The HEXACO Personality Space Before and After Re-Rotation to Approximate the Big Five Dimensions

We re-oriented the HEXACO personality dimensions to approximate the Big Five, using two measures of the Big Five as targets in a derivation sample and then in cross-validation samples. The HEXACO approximations of Big Five Agreeableness represented blends of HEXACO Agreeableness, Emotionality, and Honesty-Humility. The HEXACO approximations of Big Five Neuroticism represented blends of Emotionality with low Agreeableness and low Extraversion. The residual sixth dimension, unrelated to the Big Five, contrasted Honesty-Humility with HEXACO Agreeableness. We then examined, in additional samples, some correlates of the original and re-rotated HEXACO dimensions. In the original HEXACO factor space, Honesty-Humility was the strongest correlate of unethical behaviors (selfishness and cheating), participant age, and "assumed similarity" to a friend or partner. Upon re-rotation of the HEXACO factors, associations involving these variables were divided between Big Five Agreeableness and the residual sixth dimension. Sex differences were mainly associated with Emotionality but after re-rotation of the HEXACO factors were divided between Big Five Agreeableness and Neuroticism. We discuss the relative merits of the original and Big Five-targeted HEXACO dimensions with reference to the practical utility of Big Five Agreeableness and Neuroticism and the simplicity and theoretical interpretability of the original HEXACO factors.

Individual-Specific Animated Profiles of Mental Health

How important is the timing of the pretreatment evaluation? If we consider mental health to be a relatively fixed condition, the specific timing (e.g., day, hour) of the evaluation is immaterial and often determined on the basis of technical considerations. Indeed, the fundamental assumption underlying the vast majority of psychotherapy research and practice is that mental health is a state that can be captured in a one-dimensional snapshot. If this fundamental assumption, underlying 80 years of empirical research and practice, is incorrect, it may help explain why for decades psychotherapy failed to rise above the 50% efficacy rate in the treatment of mental-health disorders, especially depression, a heterogeneous disorder and the leading cause of disability worldwide. Based on recent studies suggesting within-individual dynamics, this article proposes that mental health and its underlying therapeutic mechanisms have underlying intrinsic dynamics that manifest across dimensions. Computational psychotherapy is needed to develop individual-specific pretreatment animated profiles of mental health. Such individual-specific animated profiles are expected to improve the ability to select the optimal treatment for each patient, devise adequate treatment plans, and adjust them on the basis of ongoing evaluations of mental-health dynamics, creating a new understanding of therapeutic change as a transition toward a more adaptive animated profile.

Does the interplay of emotion-related personality traits and reproductive hormones predict individual variation in emotion recognition?

Person-related variation has been identified in many socio-cognitive domains, and there is evidence for links between certain personality traits and individual emotion recognition. Some studies, utilizing the menstrual cycle as a hormonal model, attempted to demonstrate that hormonal fluctuations could predict variations in emotion recognition, but with merely inconsistent findings. Remarkably, the interplay between hormone fluctuations and other person-related factors that could potentially influence emotion recognition remains understudied. In the current study, we examined if the interactions of emotion-related personality traits, namely openness, extraversion, and neuroticism, and the ovulatory cycle predict individual variation in facial emotion recognition in healthy naturally cycling women. We collected salivary ovarian hormones measures from N = 129 (n = 72 validated via LH test) women across their late follicular and mid-luteal phases of the ovulatory cycle. The results revealed a negative association between neuroticism scores and emotion recognition when progesterone levels (within-subject) were elevated. However, the results did not indicate a significant moderating influence of neuroticism, openness, and extraversion on emotion recognition across phases (late follicular vs. mid-luteal) of the menstrual cycle. Additionally, there was no significant interaction between openness or extraversion and ovarian hormone levels in predicting facial emotion recognition. The current study suggests future lines of research to compare these findings in a clinical setting, as both neuroticism and ovarian hormone dysregulation are associated with some psychiatric disorders such as premenstrual dysphoric disorder (PMDD).

Facial Expression of TIPI Personality and CHMP-Tri Psychopathy Traits in Chimpanzees (Pan troglodytes) : Evidence for Honest Signalling?

Honest signalling theory suggests that humans and chimpanzees can extract socially relevant information relating to personality from the faces of their conspecifics. Humans are also able to extract information from chimpanzees' faces. Here, we examine whether personality characteristics of chimpanzees, including measures of psychopathy, can be discerned based purely on facial morphology in photographs. Twenty-one chimpanzees were given naïve and expert personality ratings on the Ten Item Personality Inventory (TIPI) and the Chimpanzee Triarchic Model of Psychopathy (CHMP-Tri) before and following behavioural observations. Characteristics relating to openness, conscientiousness, extraversion, and disinhibition could be distinguished from the faces of chimpanzees. Individuals higher on disinhibition have lower scores on conscientiousness and emotional stability and higher scores on extraversion, while those higher on meanness have lower conscientiousness and agreeableness. Facial expressions are linked to personality traits present in the TIPI and CHMP-Tri models: the Relaxed Face and the Grooming Face were displayed more by chimpanzees higher on agreeableness, whereas the Compressed Lips Face was observed more in those individuals higher on boldness, and the Full Open Grin was displayed more by chimpanzees higher on extraversion but lower on emotional stability and conscientiousness. Facial expressions were also found to be associated with particular behavioural contexts, namely the Grooming Face in affiliative contexts and the Relaxed and Relaxed Open Mouth Faces in neutral contexts. Dominant chimpanzees display higher levels of boldness and more Compressed Lips Faces, Relaxed Open Mouth Faces, and Grooming Faces than subordinate individuals. These findings support and extend evidence for an honest signalling system and a personality structure shared between humans and chimpanzees. Future research could further explore how personality is conveyed through the face, perhaps through more than just singular aspects of character, and maybe reflecting what chimpanzees themselves are able to do.

Physiological plasticity in elephants: highly dynamic glucocorticoids in African and Asian elephants

Slowly reproducing and long-lived terrestrial mammals are often more at risk from challenges that influence fitness and survival. It is, therefore, important to understand how animals cope with such challenges and how coping mechanisms translate over generations and affect phenotypic plasticity. Rapidly escalating anthropogenic challenges may further diminish an animal's ability to reinstate homeostasis. Research to advance insights on elephant stress physiology has predominantly focused on relative or comparative analyses of a major stress response marker, glucocorticoids (GCs), across different ecological, anthropogenic, and reproductive contexts. This paper presents an extensive review of published findings on Asian and African elephants from 1980 to 2023 (May) and reveals that stress responses, as measured by alterations in GCs in different sample matrices, often are highly dynamic and vary within and across individuals exposed to similar stimuli, and not always in a predictable fashion. Such dynamicity in physiological reactivity may be mediated by individual differences in personality traits or coping styles, ecological conditions, and technical factors that often are not considered in study designs. We describe probable causations under the 'Physiological Dynamicity Model', which considers context-experience-individuality effects. Highly variable adrenal responses may affect physiological plasticity with potential fitness and survival consequences. This review also addresses the significance of cautious interpretations of GCs data in the context of normal adaptive stress versus distress. We emphasize the need for long-term assessments of GCs that incorporate multiple markers of 'stress' and 'well-being' to decipher the probable fitness consequences of highly dynamic physiological adrenal responses in elephants. Ultimately, we propose that assessing GC responses to current and future challenges is one of the most valuable and informative conservation tools we have for guiding conservation strategies.

Genomic Signatures of Local Adaptation under High Gene Flow in Lumpfish-Implications for Broodstock Provenance Sourcing and Larval Production

Aquaculture of the lumpfish (Cyclopterus lumpus L.) has become a large, lucrative industry owing to the escalating demand for "cleaner fish" to minimise sea lice infestations in Atlantic salmon mariculture farms. We used over 10K genome-wide single nucleotide polymorphisms (SNPs) to investigate the spatial patterns of genomic variation in the lumpfish along the coast of Norway and across the North Atlantic. Moreover, we applied three genome scans for outliers and two genotype-environment association tests to assess the signatures and patterns of local adaptation under extensive gene flow. With our 'global' sampling regime, we found two major genetic groups of lumpfish, i.e., the western and eastern Atlantic. Regionally in Norway, we found marginal evidence of population structure, where the population genomic analysis revealed a small portion of individuals with a different genetic ancestry. Nevertheless, we found strong support for local adaption under high gene flow in the Norwegian lumpfish and identified over 380 high-confidence environment-associated loci linked to gene sets with a key role in biological processes associated with environmental pressures and embryonic development. Our results bridge population genetic/genomics studies with seascape genomics studies and will facilitate genome-enabled monitoring of the genetic impacts of escapees and allow for genetic-informed broodstock selection and management in Norway.

Exploratory preferences explain the human fascination for imaginary worlds in fictional stories

Imaginary worlds are present and often central in many of the most culturally successful modern narrative fictions, be it in novels (e.g., Harry Potter), movies (e.g., Star Wars), video games (e.g., The Legend of Zelda), graphic novels (e.g., One Piece) and TV series (e.g., Game of Thrones). We propose that imaginary worlds are popular because they activate exploratory preferences that evolved to help us navigate the real world and find new fitness-relevant information. Therefore, we hypothesize that the attraction to imaginary worlds is intrinsically linked to the desire to explore novel environments and that both are influenced by the same underlying factors. Notably, the inter-individual and cross-cultural variability of the preference for imaginary worlds should follow the inter-individual and cross-cultural variability of exploratory preferences (with the personality trait Openness-to-experience, age, sex, and ecological conditions). We test these predictions with both experimental and computational methods. For experimental tests, we run a pre-registered online experiment about movie preferences (N = 230). For computational tests, we leverage two large cultural datasets, namely the Internet Movie Database (N = 9424 movies) and the Movie Personality Dataset (N = 3.5 million participants), and use machine-learning algorithms (i.e., random forest and topic modeling). In all, consistent with how the human preference for spatial exploration adaptively varies, we provide empirical evidence that imaginary worlds appeal more to more explorative people, people higher in Openness-to-experience, younger individuals, males, and individuals living in more affluent environments. We discuss the implications of these findings for our understanding of the cultural evolution of narrative fiction and, more broadly, the evolution of human exploratory preferences.

The Misguided Veneration of Averageness in Clinical Neuroscience: A Call to Value Diversity over Typicality

Research and practice in clinical neurosciences often involve cognitive assessment. However, this has traditionally used a nomothetic approach, comparing the performance of patients to normative samples. This method of defining abnormality places the average test performance of neurologically healthy individuals at its center. However, evidence suggests that neurological 'abnormalities' are very common, as is the diversity of cognitive abilities. The veneration of central tendency in cognitive assessment, i.e., equating typicality with healthy or ideal, is, I argue, misguided on neurodiversity, bio-evolutionary, and cognitive neuroscientific grounds. Furthermore, the use of average performance as an anchor point for normal performance is unreliable in practice and frequently leads to the mischaracterization of cognitive impairments. Examples are explored of how individuals who are already vulnerable for socioeconomic reasons can easily be over-pathologized. At a practical level, by valuing diversity rather than typicality, cognitive assessments can become more idiographic and focused on change at the level of the individual. The use of existing methods that approach cognitive assessment ideographically is briefly discussed, including premorbid estimation methods and informant reports. Moving the focus away from averageness to valuing diversity for both clinical cognitive assessments and inclusion of diverse groups in research is, I argue, a more just and effective way forward for clinical neurosciences.

The psychological causes and societal consequences of authoritarianism

Over the past two decades, citizens’ political rights and civil liberties have declined globally. Psychological science can play an instrumental role in both explaining and combating the authoritarian impulses that underlie these attacks on personal autonomy. In this Review, we describe the psychological processes and situational factors that foster authoritarianism, as well as the societal consequences of its apparent resurgence within the general population. First, we summarize the dual process motivational model of ideology and prejudice, which suggests that viewing the world as a dangerous, but not necessarily competitive, place plants the psychological seeds of authoritarianism. Next, we discuss the evolutionary, genetic, personality and developmental antecedents to authoritarianism and explain how contextual threats to safety and security activate authoritarian predispositions. After examining the harmful consequences of authoritarianism for intergroup relations and broader societal attitudes, we discuss the need to expand the ideological boundaries of authoritarianism and encourage future research to investigate both right-wing and left-wing variants of authoritarianism.

Authoritarianism weakens democratic institutions and fosters societal divisions. In this Review, Osborne et al. describe the psychological processes and situational factors that give rise to authoritarianism, as well as the societal consequences of its apparent resurgence within the general population.

The prospective power of personality for childbearing: a longitudinal study based on data from Germany

The link between personality and fertility is relatively underexplored. Moreover, there are only a few studies focusing on the prospective association between personality and childbearing. However, none of these studies considered the Five-Factor Model (FFM), which is the most widely accepted measurement of personality. The present study fills this gap by examining the prospective association between the FFM and the hazard ratio of the first and the second childbirth in Germany. Analyses are based on recent data (2005–2017) from the Socio-economic Panel Study. Cox proportional hazard models are applied. Findings demonstrate that personality traits are associated with fertility. Extraversion is positively linked with the first childbirth, but is negatively associated with the second childbirth. These findings are mainly driven by males. Agreeableness is positively linked with the first childbirth across the total sample. Again, this correlation is mainly based on the findings for men, among whom a positive association between agreeableness and the second childbirth is also found. Among women, personality does not seem to be linked with the first childbirth. However, the risk of having a second child is found to be negatively associated with conscientiousness. My study adds to the current understanding of the personality–fertility association by exploring the impact of personality trait scores from the FFM on subsequent fertility behavior. However, further research is needed on the association between personality and childbearing; on the mechanisms through which personality affects fertility; and on how these links differ across cultures, among higher parities, and for births after re-partnering.

Personality Trait Patterns Moderate the Simple Model of Environmental Citizenship

The current study investigates the Simple Model of Environmental Citizenship (SMEC) in a representative sample of Lithuanian emerging adults. The SMEC is a practical model of assessing environmental citizenship and is intended to be simple to use in interventions and longitudinal research. A total of 700 individuals (50% female) with a mean age of 30.6 years participated in the survey. The participants filled in a questionnaire comprising measures assessing all the components of the SMEC as well as a personality trait measure. Participants were clustered by their personality traits and the resulting profiles were used as a moderator for the SMEC. The results revealed that the SMEC functions differently for individuals possessing different personality trait patterns and that in order to promote environmental citizenship or to engage in education for environmental citizenship, different strategies might be more effective for different individuals.

The personality profile of IPS employment specialists, and how it relates to job satisfaction: A longitudinal cohort study

The role of the Individual Placement and Support (IPS) employment specialist is a new type of occupation within mental healthcare. High turnover among employment specialists necessitates improvement in their recruitment and retention. One element that impacts retention is job satisfaction. We assessed the personality of 38 employment specialists (Big 5 Inventory-2) and measured job satisfaction over three time periods. Compared to norm data, employment specialists were significantly higher on Extraversion (ΔT = 8.0, CI: 5.59-10.42), Agreeableness (ΔT = 7.8, CI: 5.56-10.12), Conscientiousness (ΔT = 3.3, CI: 0.8-5.84), Open-mindedness (ΔT = 3.5, CI: 0.97-6.07), while lower on Negative emotionality (ΔT = -3.5, CI: -6.5 to -0.42). Extraversion had a substantial longitudinal positive effect on job satisfaction (β at T1 = 0.39; CI: 0.10-0.73) (β at T2 = 0.40; CI: 0.03-0.80), while Negative emotionality - a substantial negative effect (β at T1 = -0.60; CI: -0.90 to -0.30) (β at T2 = -0.50; CI: -0.90 to -0.12). Male gender was significantly associated with higher job satisfaction at the time point 1 (β = -0.46; CI: -0.80 to -0.14). Age, length of employment in the role, Agreeableness, Conscientiousness and Open-mindedness were not found to have substantial significant effects on job satisfaction of employment specialists. Recruiting employment specialists who score high on Extraversion and low on Negative emotionality may be a good fit for the role and job satisfaction.

The evolution of personality disorders: A review of proposals

Personality disorders (PDs) are currently considered dysfunctions. However, personality differences are older than humanity and are ubiquitous in nature, from insects to higher primates. This suggests that a number of evolutionary mechanisms-other than dysfunctions-may be able to maintain stable behavioral variation in the gene pool. First of all, apparently maladaptive traits may actually improve fitness by enabling better survival or successful mating or reproduction, as exemplified by neuroticism, psychopathy, and narcissism. Furthermore, some PDs may harm important biological goals while facilitating others, or may be globally beneficial or detrimental depending on environmental circumstances or body condition. Alternatively, certain traits may form part of life history strategies: Coordinated suites of morphological, physiological and behavioral characters that optimize fitness through alternative routes and respond to selection as a whole. Still others may be vestigial adaptations that are no longer beneficial in present times. Finally, variation may be adaptative in and by itself, as it reduces competition for finite resources. These and other evolutionary mechanisms are reviewed and illustrated through human and non-human examples. Evolutionary theory is the best-substantiated explanatory framework across the life sciences, and may shed light on the question of why harmful personalities exist at all.

The social evolution of individual differences: Future directions for a comparative science of personality in social behavior

Personality is essential for understanding the evolution of cooperation and conflict in behavior. However, personality science remains disconnected from the field of social evolution, limiting our ability to explain how personality and plasticity shape phenotypic adaptation in social behavior. Researchers also lack an integrative framework for comparing personality in the contextualized and multifaceted behaviors central to social interactions among humans and other animals. Here we address these challenges by developing a social evolutionary approach to personality, synthesizing theory, methods, and organizing questions in the study of individuality and sociality in behavior. We critically review current measurement practices and introduce social reaction norm models for comparative research on the evolution of personality in social environments. These models demonstrate that social plasticity affects the heritable variance of personality, and that individual differences in social plasticity can further modify the rate and direction of adaptive social evolution. Future empirical studies of frequency- and density-dependent social selection on personality are crucial for further developing this framework and testing adaptive theory of social niche specialization.

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.

The neurobiology of obsessive-compulsive personality disorder: a systematic review

BACKGROUND

A number of recent investigations have focused on the neurobiology of obsessive-compulsive personality disorder (OCPD). However, there have been few reviews of this literature with no detailed model proposed. We therefore undertook a systematic review of these investigations, aiming to map the available evidence and investigate whether it is possible to formulate a detailed model of the neurobiology of OCPD.

METHODS

OCPD can be considered from both categorical and dimensional perspectives. An electronic search was therefore conducted using terms that would address not only OCPD as a category, but also related constructs, such as perfectionism, that would capture research on neuropsychology, neuroimaging, neurochemistry, and neurogenetics.

RESULTS

A total of 1059 articles were retrieved, with 87 ultimately selected for abstract screening, resulting in a final selection of 49 articles focusing on neurobiological investigations relevant to OCPD. Impaired executive function and cognitive inflexibility are common neuropsychological traits in this condition, and suggest that obsessive-compulsive disorder (OCD) and OCPD may lie on a continuum. However, neuroimaging studies in OCPD indicate the involvement of specific neurocircuitry, including the precuneus and amygdala, and so suggest that OCD and OCPD may have important differences. Although OCPD has a heritable component, we found no well-powered genetic studies of OCPD.

CONCLUSION

Although knowledge in this area has advanced, there are insufficient data on which to base a comprehensive model of the neurobiology of OCPD. Given the clinical importance of OCPD, further work to understand the mechanisms that underpin this condition is warranted.

A Double-Track Pathway to Fast Strategy in Humans and Its Personality Correlates

The fast-slow paradigm of life history (LH) focuses on how individuals grow, mate, and reproduce at different paces. This paradigm can contribute substantially to the field of personality and individual differences provided that it is more strictly based on evolutionary biology than it has been so far. Our study tested the existence of a fast-slow continuum underlying indicators of reproductive effort-offspring output, age at first reproduction, number and stability of sexual partners-in 1,043 outpatients with healthy to severely disordered personalities. Two axes emerged reflecting a double-track pathway to fast strategy, based on restricted and unrestricted sociosexual strategies. When rotated, the fast-slow and sociosexuality axes turned out to be independent. Contrary to expectations, neither somatic effort-investment in status, material resources, social capital, and maintenance/survival-was aligned with reproductive effort, nor a clear tradeoff between current and future reproduction was evident. Finally, we examined the association of LH axes with seven high-order personality pathology traits: negative emotionality, impulsivity, antagonism, persistence-compulsivity, subordination, and psychoticism. Persistent and disinhibited subjects appeared as fast-restricted and fast-unrestricted strategists, respectively, whereas asocial subjects were slow strategists. Associations of LH traits with each other and with personality are far more complex than usually assumed in evolutionary psychology.

Opinions and options about COVID-19: Personality correlates and sex differences in two European countries

In the initial months of the COVID-19 pandemic in 2020, we collected data (N = 1,420) from Portugal and Spain in relation to personality (i.e., Dark Triad traits, Big Five traits, religiousness, and negative affect) and attitudes related to COVID-19 about its origins, opinions on how to deal with it, and fear of it. The most pervasive patterns we found were: (1) neurotic-type dispositions were associated with stronger opinions about the origins of the virus and leave people to have more fear of the virus but also more trust in tested establishments to provide help. (2): religious people were less trusting of science, thought prayer was answer, and attributed the existence of the virus to an act of God. We also found that sex differences and country differences in attitudes towards COVID-19 were mediate by sex/country differences in personality traits like emotional stability, religiousness, and negative affect. For instance, women reported more fear of COVID-19 than men did, and this was verified by women’s greater tendency to have negative affect and low emotional stability relative to men. Results point to the central role of neuroticism in accounting for variance in broad-spectrum attitudes towards COVID-19.

Specialised minds: extending adaptive explanations of personality to the evolution of psychopathology

Traditional evolutionary theory invoked natural and sexual selection to explain species- and sex-typical traits. However, some heritable inter-individual variability in behaviour and psychology - personality - is probably adaptive. Here we extend this insight to common psychopathological traits. Reviewing key findings from three background areas of importance - theoretical models, non-human personality and evolved human social dynamics - we propose that a combination of social niche specialisation, negative frequency-dependency, balancing selection and adaptive developmental plasticity should explain adaptation for individual differences in psychology - 'specialised minds' - explaining some variance in personality and psychopathology trait dimensions, which share various characteristics. We suggest that anthropological research of behavioural differences should be extended past broad demographic factors (age and sex) to include individual specialisations. As a first step towards grounding psychopathology in ancestral social structure, we propose a minimum plausible prevalence, given likely ancestral group sizes, for negatively frequency-dependent phenotypes to be maintained as specialised tails of adaptive distributions - below the calculated prevalence, specialisation is highly unlikely. For instance, chronic highly debilitating forms of autism or schizophrenia are too rare for such explanations, whereas attention-deficit-hyperactivity disorder and broad autism phenotypes are common enough to have existed in most hunter-gatherer bands, making adaptive explanations more plausible.

Integrating Evolutionary, Cultural, and Computational Psychiatry: A Multilevel Systemic Approach

This paper proposes an integrative perspective on evolutionary, cultural and computational approaches to psychiatry. These three approaches attempt to frame mental disorders as multiscale entities and offer modes of explanations and modeling strategies that can inform clinical practice. Although each of these perspectives involves systemic thinking, each is limited in its ability to address the complex developmental trajectories and larger social systemic interactions that lead to mental disorders. Inspired by computational modeling in theoretical biology, this paper aims to integrate the modes of explanation offered by evolutionary, cultural and computational psychiatry in a multilevel systemic perspective. We apply the resulting Evolutionary, Cultural and Computational (ECC) model to Major Depressive Disorder (MDD) to illustrate how this integrative approach can guide research and practice in psychiatry.

Toward the Development and Validation of a Model of Environmental Citizenship of Young Adults

Growing civic participation in environmental movements shows that societies are more engaging in behavior that can be described as environmental citizenship. This behavior, however, may not necessarily be driven by factual knowledge and accurate beliefs. In the present study, a simplified model of environmental citizenship proposed by Hawthorne and Alabaster is tested in a sample of Lithuanian young adults in order to develop a working model of environmental citizenship that could be later used in intervention designs as a change model. A convenience sample of 267 young adults from 18 to 40 years of age participated in the study by filling in a questionnaire that assessed various components that comprise a model of environmental citizenship. The results indicate that, with a few modifications to better fit the data, the model fit the data well and could explain approximately 50% of the variance of environmental citizenship. The study uncovered a gap between factual (concrete) environmental knowledge and environmental literacy (perceived competence), illustrating the need to address this divide in order to ensure evidence-based participation in environmental movements and environmental citizenship behavior.

The relationships between toad behaviour, antipredator defences, and spatial and sexual variation in predation pressure

BACKGROUND

Animal behaviour is under strong selection. Selection on behaviour, however, might not act in isolation from other fitness-related traits. Since predators represent outstanding selective forces, animal behaviour could covary with antipredator defences, such that individuals better suited against predators could afford facing the costs of riskier behaviours. Moreover, not all individuals undergo equivalent degrees of predation pressure, which can vary across sexes or habitats. Individuals under lower predation pressure might also exhibit riskier behaviours.

METHODS

In this work, I tested these hypotheses on natterjack toads (Epidalea calamita). Specifically, I gauged activity time, exploratory behaviour and boldness in standard laboratory conditions, and assessed whether they correlated with body size and antipredator strategies, namely sprint speed, parotoid gland area and parotoid gland colour contrast. Additionally, I compared these traits between sexes and individuals from an agrosystem and pine grove, since there is evidence that males and agrosystem individuals are subjected to greater predation pressure.

RESULTS

Sprint speed as well as parotoid gland contrast and size appeared unrelated to the behavioural traits studied. In turn, body mass was negatively related to activity time, boldness and exploration. This trend is consistent with the fact that larger toads could be more detectable to their predators, which are mostly gape unconstrained and could easily consume them. As predicted, females exhibited riskier behaviours. Nonetheless, agrosystem toads did not differ from pine grove toads in the behavioural traits measured, despite being under stronger predation pressure.

A meta-analysis of sex differences in animal personality: no evidence for the greater male variability hypothesis

The notion that men are more variable than women has become embedded into scientific thinking. For mental traits like personality, greater male variability has been partly attributed to biology, underpinned by claims that there is generally greater variation among males than females in non-human animals due to stronger sexual selection on males. However, evidence for greater male variability is limited to morphological traits, and there is little information regarding sex differences in personality-like behaviours for non-human animals. Here, we meta-analysed sex differences in means and variances for over 2100 effects (204 studies) from 220 species (covering five broad taxonomic groups) across five personality traits: boldness, aggression, activity, sociality and exploration. We also tested if sexual size dimorphism, a proxy for sex-specific sexual selection, explains variation in the magnitude of sex differences in personality. We found no significant differences in personality between the sexes. In addition, sexual size dimorphism did not explain variation in the magnitude of the observed sex differences in the mean or variance in personality for any taxonomic group. In sum, we find no evidence for widespread sex differences in variability in non-human animal personality.

Disease Prevalence and Fatality, Life History Strategies, and Behavioral Control of the COVID Pandemic

The COVID-19 pandemic caught the world by surprise and raised many questions. One of the questions is whether infectious diseases indeed drive fast life history (LH) as the extent research suggests. This paper challenges this assumption and raises a different perspective. We argue that infectious diseases enact either slower or faster LH strategies and the related disease control behavior depending on disease severity. We tested and supported the theorization based on a sample of 662 adult residents drawn from all 32 provinces and administrative regions of mainland China. The findings help to broaden LH perspectives and to better understand unusual social phenomena arising from the COVID-19 pandemic.

Who Speaks Up?

Abstract. Research on the relationship between personality traits and employee voice has predominantly focused on main effects of one or more traits and has shown equivocal results. In this study, we explore relationships between configurations (i.e., all logically possible combinations) of the Big Five traits and promotive and prohibitive voice using fuzzy-set qualitative comparative analysis. Survey data from 171 employees from 10 organizations in the service industry revealed that none of the traits alone could induce promotive or prohibitive voice. Yet, we found three trait configurations that relate to promotive voice and four configurations that relate to prohibitive voice. We use the theory of purposeful work behavior to explain the different trait configurations for promotive and prohibitive voice.

Do Early Life Experiences Predict Variation in the General Factor of Personality (GFP)?

Objective

The controversial General Factor of Personality (GFP) has been proposed as an indicator of social effectiveness and a slower life history strategy. An alternative hypothesis holds that only meta-trait alpha, comprising agreeableness, conscientiousness, and emotional stability, is a slow life history indicator. This study tested whether the GFP and/or alpha emerges from both self- and stranger-ratings, and whether either is predicted by indicators of harsh childhood ecologies.

Methods

U.S. undergraduate participants (N = 366) completed a Big Five instrument, a measure of socially desirable response bias, and brief (thin slice) videotaped interviews. Raters scored the interviews using the same Big Five instrument.

Results

Structural equation modeling of the self-report data yielded a well-fitting GFP, which was positively associated with father closeness. Meta-trait alpha, based on self-report, was associated with both father closeness and neighborhood stress, but showed positive loadings only for agreeableness and emotional stability. Stranger-rating data failed to yield either a well-fitting GFP or metatrait alpha.

Conclusions

Our findings are equivocal regarding the usefulness of the GFP specifically, and higher-order personality factors generally, in evolutionary personality science.

On the relations between HEXACO agreeableness (versus anger) and honesty-humility

The HEXACO personality factors of Agreeableness-versus-Anger (A) and Honesty-Humility (H) are interpreted as two complementary aspects of reciprocal altruistic tendency. Here we consider several ways of representing the positive associations between the defining traits of A and of H, through common factor analysis of self-report HEXACO Personality Inventory-Revised (HEXACO-PI-R) facet scale scores (N ≈ 111,000). We describe orthogonal solutions that differ in the extent to which H facets show secondary loadings on A (and vice versa), as well as an oblique solution compatible with a higher-order "cooperativeness" factor. We discuss the psychological plausibility of these solutions, and we review research showing differential associations of several phenomena or outcomes with A and H. We conclude that the optimal representation of A/H trait associations is not yet known but that the value of separate A and H factor scales is well established.

Personality Psychology

Personality psychology, which seeks to study individual differences in thoughts, feelings, and behaviors that persist over time and place, has experienced a renaissance in the last few decades. It has also not been reviewed as a field in the Annual Review of Psychology since 2001. In this article, we seek to provide an update as well as a meta-organizational structure to the field. In particular, personality psychology has a prescribed set of four responsibilities that it implicitly or explicitly tackles as a field: (a) describing what personality is-i.e., what the units of analysis in the field are; (b) documenting how it develops; (c) explaining the processes of personality and why they affect functioning; and (d) providing a framework for understanding individuals and explaining their actions, feelings, and motivations. We review progress made over the last 20 years to address these four agendas and conclude by highlighting future directions and ongoing challenges to the field. Expected final online publication date for the Annual Review of Psychology, Volume 73 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Collective action or individual choice: Spontaneity and individuality contribute to decision-making in Drosophila

Our own unique character traits make our behavior consistent and define our individuality. Yet, this consistency does not entail that we behave repetitively like machines. Like humans, animals also combine personality traits with spontaneity to produce adaptive behavior: consistent, but not fully predictable. Here, we study an iconically rigid behavioral trait, insect phototaxis, that nevertheless also contains both components of individuality and spontaneity. In a light/dark T-maze, approximately 70% of a group of Drosophila fruit flies choose the bright arm of the T-Maze, while the remaining 30% walk into the dark. Taking the photopositive and the photonegative subgroups and re-testing them reveals the spontaneous component: a similar 70–30 distribution emerges in each of the two subgroups. Increasing the number of choices to ten choices, reveals the individuality component: flies with an extremely negative series of first choices were more likely to show photonegative behavior in subsequent choices and vice versa. General behavioral traits, independent of light/dark preference, contributed to the development of this individuality. The interaction of individuality and spontaneity together explains why group averages, even for such seemingly stereotypical behaviors, are poor predictors of individual choices.

Sensitivity, but to which environment? Individual differences in sensitivity to parents and peers show domain-specific patterns and a negative genetic correlation

The idea that individuals differ in their sensitivity to the environment's effects is a cornerstone of developmental science. It has been demonstrated repeatedly, for different kinds of stressors, outcomes, and sensitivity markers. However, almost no empirical work was done to examine whether environmental sensitivity is domain-general (i.e., the same individuals are sensitive to different environmental contexts) or domain-specific (i.e., different individuals are sensitive to different environmental contexts), despite its importance to understanding human development, learning, and behavior. To address this question, phenotypic sensitivity to parents and to peers were compared in 1313 11-year-old Israeli adolescent twins. We found that, (1) our phenotypic markers indeed moderate environmental influences, with a discriminant predictive utility, (2) adolescents who are sensitive to their parents are not necessarily sensitive to their peers, and (3) sensitivity to parents and sensitivity to peers have different etiologies and show a negative genetic correlation, indicating that adolescents carrying genetic markers for sensitivity to parents are less likely to carry genetic markers for sensitivity to peers. These findings suggest that environmental sensitivity shows domain-specific patterns, as different individuals can be sensitive to different environments. We discuss the theoretical, empirical, and practical implications of domain-specificity of environmental sensitivity.

Advancing the Psychometric Study of Human Life History Indicators : K Does Not Measure Life History Speed, but Theory and Evidence Suggest It Deserves Further Attention

In this article we attend to recent critiques of psychometric applications of life history (LH) theory to variance among humans and develop theory to advance the study of latent LH constructs. We then reanalyze data (n = 4,244) previously examined by Richardson et al. (Evolutionary Psychology, 15(1), 2017, https://doi.org/10.1177/1474704916666840 to determine whether (a) previously reported evidence of multidimensionality is robust to the modeling approach employed and (b) the structure of LH indicators is invariant by sex. Findings provide further evidence that a single LH dimension is implausible and that researchers should cease interpreting K-factor scores as empirical proxies for LH speed. In contrast to the original study, we detected a small inverse correlation between mating competition and Super-K that is consistent with a trade-off. Tests of measurement invariance across the sexes revealed evidence of metric invariance (i.e., equivalence of factor loadings), consistent with the theory that K is a proximate cause of its indicators; however, evidence of partial scalar invariance suggests use of scores likely introduces bias when the sexes are compared. We discuss limitations and identify approaches that researchers may use to further evaluate the validity of the K-factor and other applications of LH to human variation.

Personality-informed intervention design: Examining how trait regulation can inform efforts to change behavior

Research that helps people change their behavior has the potential to improve the quality of lives, but it is too often approached in a way that divorces behavior from the people who need to enact it. In this paper, we propose a personality-informed approach to classifying behavior-change problems and designing interventions to address them. In particular, we argue that interventions will be most effective when they target the appropriate psychological process given the disposition of the participant and the desired duration of change. Considering these dimensions can help to reveal the differences among common types of behavior-change problems, and it can guide decisions about what kinds of intervention solutions will most effectively solve them. We review key concepts and findings from the personality literature that can help us understand the dynamic nature of dispositions and to identify the psychological processes that best explain both short-term variance in behavior and long-term development of personality. Drawing on this literature, we argue that different types of behavior-change problems require different forms of “trait regulation,” and we offer a series of propositions to be evaluated as potential guides for the design of intervention strategies to address them.