Suicidal Risk During Adolescence: Could Covitality Be Part of the Solution?

OBJECTIVE

The covitality model suggests that the co-disposition and synergy of core psychosocial assets (i.e., covitality) buffer the negative impact of stressful events and prevent the emergence of mental health problems during adolescence. At this stage of development, suicide already constitutes the leading cause of unnatural death in Europe. The present study aimed to examine how covitality relates to bidimensional mental health status (i.e., psychopathology and subjective well-being) and suicidal risk.

METHOD

Participants were 5,296 Spanish students ages 12 to 18 years (Mage ± SD = 14.19 ± 1.53), 50.2% male.

RESULTS

In a structural equation mediational model, covitality acted as a powerful shield of psychosocial strengths against suicidality, via an indirect effect entirely mediated by its impact on bidimensional mental health. The total variance in suicidal risk explained by the set of independent variables was 61.8%, while the total variance of psychopathology and subjective well-being explained by covitality was 54.1% and 75.6%, respectively.

CONCLUSIONS

These preliminary findings highlight the need for further study of covitality as a defense strategy against adolescent suicide. HIGHLIGHTSCovitality promote subjective well-being and prevent psychopathological symptoms.These self-perceived psychosocial strengths do not have direct effect on suicidality.Covitality is related to lower suicidal risk through indirect mechanisms: via bidimensional approach to mental health status (BMH).

Qualitative Behavioural Assessment of bonobo emotional expressivity across observer groups and zoo housing environments

Human evaluation of animal emotional expressivity can inform animal welfare. Qualitative Behavioural Assessment (QBA) has been applied to domesticated and some non-domesticated animals, but its use in primates is limited despite their emotional expressivity. We aimed to develop and apply a QBA for bonobos (Pan paniscus) through two consecutive studies. We applied Free Choice Profiling (FCP) and the Fixed List methodology, respectively, in Study 1 and 2, and invited students and bonobo experts to rate video clips of zoo-living bonobos of different sexes and age classes, and before and after moving to a new enclosure. In Study 1, students described dimension 1 as ranging from 'quiet/calm' to 'angry/active' and dimension 2 from 'sad/anxious' to 'happy/loving'. Experts described dimension 1 ranging from 'quiet/relaxed' to 'nervous/alert' and dimension 2 from 'nervous/bored' to 'playful/happy'. Using a fixed list of descriptors, informed by findings from Study 1, students in Study 2 described dimension 1 as ranging from 'quiet/calm' to 'agitated/frustrated', and dimension 2 from 'sad/stressed' to 'happy/positively engaged'. Experts described dimension 1 as ranging from 'quiet/calm' to 'active/excited', and dimension 2 from 'sad/bored' to 'happy/positively engaged'. Students scored adults as more 'calm/quiet' and experts scored subadults as more 'happy/positively engaged'. Additionally, experts in Study 2 rated bonobos as more 'active/excited' in their new enclosure. Reliability was moderate to good for the dimensions. Additionally, animal-directed empathy of observers influenced QBA scores. This is the first time, FCP has been successfully used as a method to study primate emotional expressivity. Our findings show the promise of employing QBA in primate studies and in industry, with validation of additional metrics to enable its use for welfare-monitoring purposes.

Emotional Well-Being: What It Is and Why It Matters

Psychological aspects of well-being are increasingly recognized and studied as fundamental components of healthy human functioning. However, this body of work is fragmented, with many different conceptualizations and terms being used (e.g., subjective well-being, psychological well-being). We describe the development of a provisional conceptualization of this form of well-being, here termed emotional well-being (EWB), leveraging prior conceptual and theoretical approaches. Our developmental process included review of related concepts and definitions from multiple disciplines, engagement with subject matter experts, consideration of essential properties across definitions, and concept mapping. Our conceptualization provides insight into key strengths and gaps in existing perspectives on this form of well-being, setting a foundation for evaluating assessment approaches, enhancing our understanding of the causes and consequences of EWB, and, ultimately, developing effective intervention strategies that promote EWB. We argue that this foundation is essential for developing a more cohesive and informative body of work on EWB.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42761-022-00163-0.

A Systematic Scoping Review of Psychological Capital Related to Mental Health in Youth

Psychological capital (PsyCap) is a term coined in organizational psychology and refers to a person's development of states that motivate behavior. Also known in the literature as PsyCap, this construct typically refers to positive states of hope, self-efficacy, resilience, and optimism that are amenable to intervention and that are related to subjective well-being and life satisfaction. The aims of this systematic scoping review were to explore how PsyCap is described in youth mental health literature and how PsyCap and mental health are related. Results from four databases were reported following PRISMA guidelines. A total of 772 studies were identified and 16 studies were fully reviewed, including an overall sample of 6,772 youth from six countries. PsyCap has a positive relationship with mental health in youth. Future studies should involve school nurses to validate the constructs that characterize PsyCap and validate an instrument for measuring PsyCap in youth mental health in English.

Taking the pulse of nations: A biometric measure of well-being

A growing literature identifies associations between subjective and biometric indicators of wellbeing. These associations, together with the ability of subjective wellbeing metrics to predict health and behavioral outcomes, have spawned increasing interest in wellbeing as an important concept in its own right. However, some social scientists continue to question the usefulness of wellbeing metrics. We contribute to this literature in three ways. First, we introduce a biometric measure of wellbeing - pulse - that hs been little used. Using nationally representative data on 165,000 individuals from the Health Survey for England and Scottish Health Surveys we show that its correlates are similar in a number of ways to those for happiness, and that it is highly correlated with wellbeing metrics, as well as self-assessed health. Second, we examine the determinants of pulse rates in mid-life (age 42) among the 9000 members of the National Child Development Study, a birth cohort born in a single week in 1958 in Britain. Third, we track the impact of pulse measured in mid-life (age 42) on health and labor market outcomes at age 50 in 2008 and age 55 in 2013. The probability of working at age 55 is negatively impacted by pulse rate a decade earlier. The pulse rate has an impact over and above chronic pain measured at age 42. General health at 55 is lower the higher the pulse rate at age 42, while those with higher pulse rates at 42 also express lower life satisfaction and more pessimism about the future at age 50. Taken together, these results suggest social scientists can learn a great deal by adding pulse rates to the metrics they use when evaluating people's wellbeing.

From human wellbeing to animal welfare

What does it mean to be "well" and how might such a state be cultivated? When we speak of wellbeing, it is of ourselves and fellow humans. When it comes to nonhuman animals, consideration turns to welfare. My aim herein is to suggest that theoretical approaches to human wellbeing might be beneficially applied to consideration of animal welfare, and in so doing, introduce new lines of inquiry and practice. I will review current approaches to human wellbeing, adopting a triarchic structure that delineates hedonic wellbeing, eudaimonic wellbeing, and social wellbeing. For each, I present a conceptual definition and a review of how researchers have endeavored to measure the construct. Drawing these three domains of research together, I highlight how these traditionally anthropocentric lines of inquiry might be extended to the question of animal welfare - namely by considering hedonic welfare, eudaimonic welfare, and social welfare as potentially distinguishable and complementary components of the broader construct of animal welfare.

Personality, subjective well-being, and the serotonin 1a receptor gene in common marmosets (Callithrix jacchus)

Studies of personality traits in common marmosets (Callithrix jacchus) indicate that there are five or six constructs-Sociability, Dominance, Neuroticism, Openness, and two related to Conscientiousness. The present study attempted to determine whether our earlier study of laboratory-housed individuals only yielded three-Dominance, Sociability, and Neuroticism-because of a low amount of between-subjects variance. To do so, we increased our sample size from 77 to 128. In addition, we ascertained the reliability and validity of ratings and whether polymorphisms related to the serotonin 1a receptor were associated with personality. We found Sociability, Dominance, and Negative Affect factors that resembled three domains found in previous studies, including ours. We also found an Openness and Impulsiveness factor, the latter of which bore some resemblance to Conscientiousness, and two higher-order factors, Pro-sociality and Boldness. In further analyses, we could not exclude the possibility that Pro-sociality and Boldness represented a higher-level of personality organization. Correlations between personality factors and well-being were consistent with the definitions of the factors. There were no significant associations between personality and genotype. These results suggest that common marmoset personality structure varies as a function of rearing or housing variables that have not yet been investigated systematically.

Taking Students on a Strengths Safari: A Multidimensional Pilot Study of School-Based Wellbeing for Young Neurodiverse Children

There is a robust body of psychological research linking youth mental health and academic achievement. However, students in early childhood are rarely represented in this research, and children with disabilities and/or neurological differences are virtually absent. Thus, the present pilot study explored the effects of a structured psychoeducation program designed to enhance school-based wellbeing (SBWB) for young students who are neurodivergent (ND). This study utilized a quasi-experimental design to investigate the effects of the Student Strengths Safari intervention on (1) students’ self-reported covitality and (2) teacher-rated executive functioning to (3) examine data for evidence of a dual-factor model of SBWB. Two classrooms in a suburban, Mid-Atlantic private school were randomly assigned to the waitlist control group (n = 14) (1st grade) and the intervention group (n = 10) (2nd grade), and quantitative data were analyzed at pretest and posttest to determine intervention outcomes. Key findings produced evidence to support (a) a statistically significant interaction effect for improvements in executive functioning relative to the waitlist control group (p = 0.011), and (b) the utility of a new theoretical dual-factor model to advance SBWB for ND students in early elementary education.

The effect of state extraversion on four types of affect

The primary purpose of this study was to determine the effect of state extraversion on different types of affect. Ninety six participants were instructed to be extraverted or introverted in a 10‐minute dyadic discussion. State extraversion had a strong effect on positive affect and smaller (but still strong) effects on pleasant and activated affect, with these latter two effects almost equal in magnitude. This pattern of findings appears to increase confidence that the effect of state extraversion is genuine rather than the result of construct overlap, in that extraversion's effect on positive affect is not dominated by its effect on activated affect. No support for reward sensitivity as a potential explanatory mechanism was found. Copyright © 2009 John Wiley & Sons, Ltd.

Greater variability in chimpanzee (Pan troglodytes) brain structure among males

Across the animal kingdom, males tend to exhibit more behavioural and morphological variability than females, consistent with the 'greater male variability hypothesis'. This may reflect multiple mechanisms operating at different levels, including selective mechanisms that produce and maintain variation, extended male development, and X chromosome effects. Interestingly, human neuroanatomy shows greater male variability, but this pattern has not been demonstrated in any other species. To address this issue, we investigated sex-specific neuroanatomical variability in chimpanzees by examining relative and absolute surface areas of 23 cortical sulci across 226 individuals (135F/91M), using permutation tests of the male-to-female variance ratio of residuals from MCMC generalized linear mixed models controlling for relatedness. We used these models to estimate sulcal size heritability, simulations to assess the significance of heritability, and Pearson correlations to examine inter-sulcal correlations. Our results show that: (i) male brain structure is relatively more variable; (ii) sulcal surface areas are heritable and therefore potentially subject to selection; (iii) males exhibit lower heritability values, possibly reflecting longer development; and (iv) males exhibit stronger inter-sulcal correlations, providing indirect support for sex chromosome effects. These results provide evidence that greater male neuroanatomical variability extends beyond humans, and suggest both evolutionary and developmental explanations for this phenomenon.

Infant rhesus macaque (Macaca mulatta) personality and subjective well-being

Infant temperament is theorized to lay the foundation for adult personality; however, many questions remain regarding personality in infancy, including the number of dimensions, extent to which they are adult-like, and their relation to other outcomes, such as mental and physical health. Here we tested whether adult-like personality dimensions are already present in infancy in a nonhuman primate species. We measured personality and subjective well-being in 7-month-old rhesus macaques (N = 55) using the Hominoid Personality Questionnaire and Subjective Well-Being Questionnaire, both of which were developed for adult primates based on human measures. Multiple human raters, who provided infants with daily care since birth, independently rated each infant. We found high interrater reliability. Results from a parallel analysis and scree plot indicated a five component structure, which, using principal components analysis, we found to be comprised of dimensions relating to Openness (e.g., curiosity, inquisitive, playfulness), Assertiveness (e.g., dominance, bullying, aggressive), Anxiety (e.g., vigilance, fearful), Friendliness (e.g., sociable, affectionate, sympathetic), and Intellect (e.g., organized, not erratic). These components are largely analogous to those in adult macaques, suggesting remarkably stable structural personality components across the lifespan. Infant macaques' subjective well-being positively correlates with Openness and Assertiveness and negatively correlated with Anxiety, similar to findings in adult macaques and other primates. Together, these findings suggest that, in macaques, infant personality dimensions may be conceptually related to adult personality and challenge the view that infant temperament may be disorganized and not as meaningful as adult personality. Further research is necessary to explore the antecedents, predictive validity, and stability of these personality components across situations and with development.

Negative Reflections About Positive Psychology: On Constraining the Field to a Focus on Happiness and Personal Achievement

“Positive” psychology has gained a dominant voice within and outside the field of psychology. Although critiques of this perspective have been rendered, including by humanistic psychologists, psychology scholars have offered minimum space for critical reflections of this movement in contrast to its critiques existing inside and outside the academia in other fields. Therefore, this contribution seeks to explicate emerging systematic critiques of positive psychology by scholars and practitioners from within mental health fields as well as from philosophy, medicine, education, business, and cultural studies and to highlight sociocultural discussions of positive movement by the culture critics. Last, we offer reflections on positive psychology as immigrant professionals from non-Western backgrounds with an emphasis on existential and humanities-based perspectives. We also highlight that the tenets and experiments based on “positive” psychological practices may have especially detrimental effect on marginalized individuals and communities. This contribution seeks to invite a critical dialogue in the field regarding positive psychology within and outside humanistic psychology and psychology in general.

The 24/7 approach to promoting optimal welfare for captive wild animals

We have an ethical responsibility to provide captive animals with environments that allow them to experience good welfare. Husbandry activities are often scheduled for the convenience of care staff working within the constraints of the facility, rather than considering the biological and psychological requirements of the animals themselves. The animal welfare 24/7 across the lifespan concept provides a holistic framework to map features of the animal's life cycle, taking into account their natural history, in relation to variations in the captive environment, across day and night, weekdays, weekends, and seasons. In order for animals to have the opportunity to thrive, we argue the need to consider their lifetime experience, integrated into the environments we provide, and with their perspective in mind. Here, we propose a welfare assessment tool based upon 14 criteria, to allow care staff to determine if their animals' welfare needs are met. We conclude that animal habitat management will be enhanced with the use of integrated technologies that provide the animals with more opportunities to engineer their own environments, providing them with complexity, choice and control.

Paternal personality and social status influence offspring activity in zebrafish

BACKGROUND

Evidence for the transmission of non-genetic information from father to offspring is rapidly accumulating. While the impact of chemical and physical factors such as toxins or diet on the fitness of the parents and their offspring have been studied extensively, the importance of behavioural and social circumstances has only recently been recognised. Behavioural traits such as personality characteristics can be relatively stable, and partly comprise a genetic component but we know little about the non-genetic transmission of plastic behavioural traits from parents to offspring. We investigated the relative effect of personality and of social dominance as indicators at the opposite ends of the plasticity range on offspring behaviour in the zebrafish (Danio rerio). We assessed male boldness, a behavioural trait that has previously been shown previously to possess genetic underpinnings, and experimentally manipulated male social status to assess the association between the two types of behaviour and their correlation with offspring activity.

RESULTS

We found a clear interaction between the relatively stable and putative genetic effects based on inherited differences in personality and the experimentally induced epigenetic effects from changes in the social status of the father on offspring activity.

CONCLUSIONS

Our study shows that offspring behaviour is determined by a combination of paternal personality traits and on-genetic effects derived from the social status of the father.

Genes, social transmission, but not maternal effects influence responses of wild Japanese macaques (Macaca fuscata) to novel-object and novel-food tests

Using long-term maternal pedigree data, microsatellite analysis, and behavioral tests, we examined whether personality differences in wild Japanese macaques (Macaca fuscata) are associated with additive genetic effects, maternal influences, or belonging to a particular social group. Behaviors elicited by novel-object tests were defined by a component related to caution around novel-objects (Ob-PC1) and behaviors elicited by novel food-tests were defined by correlated components related to consummatory responses (Fo-PC1) and caution around novel foods (Fo-PC2). The repeatability of Ob-PC1 was modest and not significant; the repeatabilities of Fo-PC1 and Fo-PC2 were moderate and significant. Linear mixed effects models found that sex, age, sex × age, provisioning, trial number, date, time of day, season, and distance to the closest monkey were not related to personality. Linear mixed effects models of females older than 2 years found that high rank was associated with greater caution around novel objects. Linear models were used to determine whether sex, age, group membership, maternal kinship, or relatedness had independent effects on the personality similarity of dyads. These analyses found that pairs of macaques that lived in the same group were less similar in their caution around novel objects, more closely related pairs of macaques were more similar in their tendency to eat novel food, and that pairs of macaques in the same group were more similar in how cautious they were around novel foods. Together, these findings suggest that personality in this population of wild monkeys was driven by rank, genetic effects, and group effects, the latter possibly including the need to exploit different niches in the environment.

Positive psychology constructs as predictors of depression in retirees

This study investigated whether five positive psychological constructs (self-efficacy, gratitude, grit, hope and optimism) had a combined effect on levels of depression. The co-occurrence of these psychological factors, defined as an example of covitality, was examined in relation to predicting lower levels of depression. Participants were 278 retirees living in Brisbane, Australia. Each participant completed either an online or hard-copy self-report, related to positive psychological functioning. A standard multiple regression found that self-efficacy, grit, optimism and hope were individually all significant predictors of depression (small effect sizes); however, the combinatorial relation of all these four factors with depression was substantial (R2 = 0.34; large effect size). Gratitude was not a significant predictor. While no causality can be inferred from this cross-sectional study, having a combination of positive psychological factors might have an effect on levels of depression in retirement.

Personality Polygenes, Positive Affect, and Life Satisfaction

Approximately half of the variation in wellbeing measures overlaps with variation in personality traits. Studies of non-human primate pedigrees and human twins suggest that this is due to common genetic influences. We tested whether personality polygenic scores for the NEO Five-Factor Inventory (NEO-FFI) domains and for item response theory (IRT) derived extraversion and neuroticism scores predict variance in wellbeing measures. Polygenic scores were based on published genome-wide association (GWA) results in over 17,000 individuals for the NEO-FFI and in over 63,000 for the IRT extraversion and neuroticism traits. The NEO-FFI polygenic scores were used to predict life satisfaction in 7 cohorts, positive affect in 12 cohorts, and general wellbeing in 1 cohort (maximal N = 46,508). Meta-analysis of these results showed no significant association between NEO-FFI personality polygenic scores and the wellbeing measures. IRT extraversion and neuroticism polygenic scores were used to predict life satisfaction and positive affect in almost 37,000 individuals from UK Biobank. Significant positive associations (effect sizes <0.05%) were observed between the extraversion polygenic score and wellbeing measures, and a negative association was observed between the polygenic neuroticism score and life satisfaction. Furthermore, using GWA data, genetic correlations of −0.49 and −0.55 were estimated between neuroticism with life satisfaction and positive affect, respectively. The moderate genetic correlation between neuroticism and wellbeing is in line with twin research showing that genetic influences on wellbeing are also shared with other independent personality domains.

Comparison of Subjective Well-Being and Personality Assessments in the Clouded Leopard (Neofelis nebulosa), Snow Leopard (Panthera uncia), and African Lion (Panthera leo)

The study of subjective well-being in nonhuman animals is growing in the field of psychology, but there are still only a few published studies and the focus is on primates. To consider whether the construct of subjective well-being could be found in another mammal, this study aimed to assess subjective well-being in felids and to examine its association with personality. Personality is one of the strongest and most consistent predictors of well-being in humans. This relationship could have important implications for other species, because personality has also been shown to affect health outcomes including stress, morbidity, and mortality. As in previous studies in nonhuman animals, the study results revealed that subjective well-being was related to agreeableness/openness and neuroticism in clouded leopards, neuroticism in snow leopards, and impulsiveness and neuroticism in African lions. The implications of these results for health outcomes and the welfare of animals in captivity are discussed. More research on any direct links among personality, subjective well-being, and these outcomes is important to advancing this field and adding another tool for improving captive animals' lives.

Why People Are in a Generally Good Mood

Evidence shows that people feel mild positive moods when no strong emotional events are occurring, a phenomenon known as positive mood offset. We offer an evolutionary explanation of this characteristic, showing that it improves fertility, fecundity, and health, and abets other characteristics that were critical to reproductive success. We review research showing that positive mood offset is virtually universal in the nations of the world, even among people who live in extremely difficult circumstances. Positive moods increase the likelihood of the types of adaptive behaviors that likely characterized our Paleolithic ancestors, such as creativity, planning, mating, and sociality. Because of the ubiquity and apparent advantages of positive moods, it is a reasonable hypothesis that humans were selected for positivity offset in our evolutionary past. We outline additional evidence that is needed to help confirm that positive mood offset is an evolutionary adaptation in humans and we explore the research questions that the hypothesis generates.

Adolescent social instability stress increases aggression in a food competition task in adult male Long-Evans rats

Adolescent social instability stress (SS; daily 1 hr isolation + new cage partners postnatal days 30-45; thereafter with original cage partner, also in the SS condition) and control (CTL) rats competed for access to a preferred food in five sessions against their cage partner. In the first session, SS pairs displayed more aggression (face whacks, p = .02; rear attacks, p = .03), were less likely to relinquish access to the food voluntarily (p = .03), spent more time at the feeder than CTL pairs (p = .06), but did not differ in latency to access the feeder (p = .41). Pairs were considered in dominant-submissive relationships (DSR) if one rat spent significantly more time at the feeder than the other; 8 of 12 SS and 8 of 12 CTL pairs displayed DSRs (remaining: no-DSR). Aggression increased from the 1st to 5th session (p < .001), was greater in no-DSR than DSR pairs (p = .04; consistent with the proposed function of DSRs to be the reduction of aggression in groups), and was higher in SS than CTL pairs (p = .05). Because the increased aggression of SS compared with CTL pairs did not result in a significant increase in their time at the feeder, the increased aggression may be considered maladaptive, and may reflect an increased motivation for food reward. These results add to evidence that SS in adolescence modifies the adult social repertoire of rats and highlight the importance of adolescent social experiences for adult behavior.

Personality in chimpanzees (Pan troglodytes): exploring the hierarchical structure and associations with the vasopressin V1A receptor gene

One of the major contributions of recent personality psychology is the finding that traits are related to each other in an organized hierarchy. To date, however, researchers have yet to investigate this hierarchy in nonhuman primates. Such investigations are critical in confirming the cross-species nature of trait personality helping to illuminate personality as neurobiologically-based and evolutionarily-derived dimensions of primate disposition. Investigations of potential genetic polymorphisms associated with hierarchical models of personality among nonhuman primates represent a critical first step. The current study examined the hierarchical structure of chimpanzee personality as well as sex-specific associations with a polymorphism in the promoter region of the vasopressin V1a receptor gene (AVPR1A), a gene associated with dispositional traits, among 174 chimpanzees. Results confirmed a hierarchical structure of personality across species and, despite differences in early rearing experiences, suggest a sexually dimorphic role of AVPR1A polymorphisms on hierarchical personality profiles at a higher-order level.

Personality Traits in Rhesus Macaques (Macaca mulatta) Are Heritable but Do Not Predict Reproductive Output

There is growing evidence that behavioral tendencies, or "personalities," in animals are an important aspect of their biology, yet their evolutionary basis is poorly understood. Specifically, how individual variation in personality arises and is subsequently maintained by selection remains unclear. To address this gap, studies of personality require explicit incorporation of genetic information. Here, we explored the genetic basis of personality in rhesus macaques by determining the heritability of personality components and by examining the fitness consequences of those components. We collected observational data for 108 adult females living in three social groups in a free-ranging population via focal animal sampling. We applied principal component analysis to nine spontaneously occurring behaviors and identified six putative personality components, which we named Meek, Bold, Aggressive, Passive, Loner, and Nervous. All components were repeatable and heritable, with heritability estimates ranging from 0.14 to 0.35. We found no evidence of an association with reproductive output, measured either by infant survival or by interbirth interval, for any of the personality components. This finding suggests either that personality does not have fitness-related consequences in this population or that selection has acted to reduce fitness-associated variation in personality.

Applying Quantitative Genetic Methods to Primate Social Behavior

Increasingly, behavioral ecologists have applied quantitative genetic methods to investigate the evolution of behaviors in wild animal populations. The promise of quantitative genetics in unmanaged populations opens the door for simultaneous analysis of inheritance, phenotypic plasticity, and patterns of selection on behavioral phenotypes all within the same study. In this article, we describe how quantitative genetic techniques provide studies of the evolution of behavior with information that is unique and valuable. We outline technical obstacles for applying quantitative genetic techniques that are of particular relevance to studies of behavior in primates, especially those living in noncaptive populations, e.g., the need for pedigree information, non-Gaussian phenotypes, and demonstrate how many of these barriers are now surmountable. We illustrate this by applying recent quantitative genetic methods to spatial proximity data, a simple and widely collected primate social behavior, from adult rhesus macaques on Cayo Santiago. Our analysis shows that proximity measures are consistent across repeated measurements on individuals (repeatable) and that kin have similar mean measurements (heritable). Quantitative genetics may hold lessons of considerable importance for studies of primate behavior, even those without a specific genetic focus.

Correlational selection does not explain the evolution of a behavioural syndrome

Correlated suites of behaviours, or behavioural syndromes, appear to be widespread, and yet few studies have explored how they arise and are maintained. One possibility holds that correlational selection can generate and maintain behavioural syndrome if certain behavioural combinations enjoy greater fitness than other combinations. Here we test this correlational selection hypothesis by comparing behavioural syndrome structure with a multivariate fitness surface based on reproductive success of male water striders. We measured the structure of a behavioural syndrome including dispersal ability, exploration behaviour, latency to remount and sex recognition sensitivity in males. We then measured the relationship between these behaviours and mating success in a range of sex ratio environments. Despite the presence of some significant correlational selection, behavioural syndrome structure was not associated with correlational selection on behaviours. Although we cannot conclusively reject the correlational selection hypothesis, our evidence suggests that correlational selection and resulting linkage disequilibrium might not be responsible for maintaining the strong correlations between behaviours. Instead, we suggest alternative ways in which this behavioural syndrome may have arisen and outline the need for physiological and quantitative genetic tests of these suggestions.

Major depression and life satisfaction: a population-based twin study

BACKGROUND

The extent to which positive and negative indicators of mental health share etiological influences has been studied to a limited degree only. This study examines the genetic and environmental influences on association between liability to lifetime DSM-IV Major Depressive Disorder (MDD) and dispositional life satisfaction (LS).

METHODS

Two-wave questionnaire data on LS (assessed 6 years apart) and lifetime MDD obtained by structured clinical interviews in a population-based sample of adult twins were analysed using structural equation modelling in Mx.

RESULTS

The prevalence of lifetime MDD was estimated to be 11.1% and 15.8% in males and females, respectively. Individuals fulfilling the criteria for MDD reported significantly lower levels of LS. The co-variation in MDD and dispositional LS was found to be accounted for by genetic and unique environmental influences only. The phenotypic correlation was estimated to be 0.36, of which genetic influences accounted for 74% and environmental factors the remaining 26%. The correlation between genetic factors for MDD and LS was estimated to be -0.55 and the correlation between unique environmental factors to be -0.22. Heritability was estimated to 0.34 and 0.72 for MDD and LS, respectively.

LIMITATIONS

The sample consists of twins only and there are limitations associated with the twin design.

CONCLUSIONS

Whereas genetic influences on vulnerability to lifetime MDD are considerably shared with liability to (low) LS, environmental influences are more distinct. Thus, environmental factors associated with risk of MDD do not strongly impact on dispositional LS, and conversely, environmental factors influencing dispositional LS do not strongly buffer against MDD.

Evidence for a midlife crisis in great apes consistent with the U-shape in human well-being

Recently, economists and behavioral scientists have studied the pattern of human well-being over the lifespan. In dozens of countries, and for a large range of well-being measures, including happiness and mental health, well-being is high in youth, falls to a nadir in midlife, and rises again in old age. The reasons for this U-shape are still unclear. Present theories emphasize sociological and economic forces. In this study we show that a similar U-shape exists in 508 great apes (two samples of chimpanzees and one sample of orangutans) whose well-being was assessed by raters familiar with the individual apes. This U-shaped pattern or "midlife crisis" emerges with or without use of parametric methods. Our results imply that human well-being's curved shape is not uniquely human and that, although it may be partly explained by aspects of human life and society, its origins may lie partly in the biology we share with great apes. These findings have implications across scientific and social-scientific disciplines, and may help to identify ways of enhancing human and ape well-being.

Maternal care associates with play dominance rank among adult female rats

Variations in maternal care influence important life history traits that determine reproductive fitness. The adult female offspring of mothers that show reduced levels of pup licking/grooming (LG; i.e., low-LG mothers) show increased defensive responses to stress, accelerated pubertal development, and greater sexual receptivity than the female offspring of high-LG mothers. Amongst several species an accelerated pattern of reproductive development is associated with increased dominance-related behaviors and higher social rank. We hypothesize that rats from low-LG dams may thus also secure higher social rank as a means to compete for limited resources with conspecifics. In this study, social interactions were observed in triads of adult female rats aged p90 that received low, mid, and high levels of pup LG over the first week of life. Low- and mid-LG females had the highest pinning scores and high-LG rats the lowest, showing that low- and mid-LG adult females engage in greater play dominance-related behavior. Likewise, low- and mid-LG rats spent significantly more time drinking following 24 hr of water deprivation in a water competition test thus allowing them to secure a limited resource more easily than high-LG rats. Interestingly, pinning by play dominant females was increased when subordinates were sexually receptive (proestrus/estrus), suggestive of a process of reproductive suppression. Some evidence suggests that low-LG and mid-LG rats also show greater fecundity than high-LG rats. Variations in maternal care may thus have a long-term influence on the development of play dominance and possibly social rank in the female rat, which might contribute to reproductive success within a competitive environment.

The local-ladder effect: social status and subjective well-being

Dozens of studies in different nations have revealed that socioeconomic status only weakly predicts an individual's subjective well-being (SWB). These results imply that although the pursuit of social status is a fundamental human motivation, achieving high status has little impact on one's SWB. However, we propose that sociometric status-the respect and admiration one has in face-to-face groups (e.g., among friends or coworkers)-has a stronger effect on SWB than does socioeconomic status. Using correlational, experimental, and longitudinal methodologies, four studies found consistent evidence for a local-ladder effect: Sociometric status significantly predicted satisfaction with life and the experience of positive and negative emotions. Longitudinally, as sociometric status rose or fell, SWB rose or fell accordingly. Furthermore, these effects were driven by feelings of power and social acceptance. Overall, individuals' sociometric status matters more to their SWB than does their socioeconomic status.

Cues to Personality and Health in the Facial Appearance of Chimpanzees (Pan Troglodytes)

Humans ( Homo sapiens) and chimpanzees ( Pan troglodytes) can extract socially-relevant information from the static, non-expressive faces of conspecifics. In humans, the face is a valid signal of both personality and health. Recent evidence shows that, like humans, chimpanzee faces also contain personality information, and that humans can accurately judge aspects of chimpanzee personality relating to extraversion from the face alone (Kramer, King, and Ward, 2011). These findings suggest the hypothesis that humans and chimpanzees share a system of personality and facial morphology for signaling socially-relevant traits from the face. We sought to test this hypothesis using a new group of chimpanzees. In two studies, we found that chimpanzee faces contained health information, as well as information of characteristics relating to extraversion, emotional stability, and agreeableness, using average judgments from pairs of individual photographs. In a third study, information relating to extraversion and health was also present in composite images of individual chimpanzees. We therefore replicate and extend previous findings using a new group of chimpanzees and demonstrate two methods for minimizing the variability associated with individual photographs. Our findings support the hypothesis that chimpanzees and humans share a personality signaling system.

The majority of genetic variation in orangutan personality and subjective well-being is nonadditive

The heritability of human personality is well-established. Recent research indicates that nonadditive genetic effects, such as dominance and epistasis, play a large role in personality variation. One possible explanation for the latter finding is that there has been recent selection on human personality. To test this possibility, we estimated additive and nonadditive genetic variance in personality and subjective well-being of zoo-housed orangutans. More than half of the genetic variance in these traits could be attributed to nonadditive genetic effects, modeled as dominance. Subjective well-being had genetic overlap with personality, though less so than has been found in humans or chimpanzees. Since a large portion of nonadditive genetic variance in personality is not unique to humans, the nonadditivity of human personality is not sufficient evidence for recent selection of personality in humans. Nonadditive genetic variance may be a general feature of the genetic structure of personality in primates and other animals.

Evidence for Shared Genetic Dominance Between the General Factor of Personality, Mental and Physical Health, and Life History Traits

We reanalyze previously published data on 309 MZ and 333 DZ twin pairs aged 25 to 74 years from the MIDUS survey, a nationally representative archived sample, to examine how much of the genetic covariance between a general factor of personality (GFP), a lower-order life history factor, and a general physical and mental health factor, is of the nonadditive variety. We found nonadditive genetic effects (D) could not be ruled out as a contributor to the shared variance of these three latent factors to a Super-K Life History factor. We suggest these genetic correlations support the view that a slow (K-selected) life history strategy, good health, and the GFP coevolved and are mutually coadapted through directional selection.

Psychological well-being (PWB): a natural life outlook? An Italian twin study on heritability of PWB in young adults

BACKGROUND

To date, the genetic and environmental architecture of the dimensions of psychological well-being (PWB) remains unexplored.

METHOD

PWB of 742 twins aged 23-24 years and enrolled in the Italian Twin Registry was assessed with the three-item version of Ryff's Scales of Psychological Well-Being (SPWB). These scales include items for evaluating the PWB dimensions of self-acceptance, positive relations with others, autonomy, environmental mastery, purpose in life, and personal growth. A twin design was used to obtain correlations in the PWB dimensions for monozygotic (MZ) and dizygotic (DZ) twins and to estimate the contribution of genetic and environmental factors to variation and covariation in the dimensions.

RESULTS

Genetic factors explained moderate to substantial proportions of variance in the six SPWB dimensions, with heritability estimates between 37% and 64%. The estimates of genetic correlations were very high (range 0.77-0.99), indicating that genetic factors that influence the expression of the different dimensions of PWB may be shared to a large extent. Non-shared environmental correlations ranged from substantial to high, with the exception of the correlation between autonomy and the dimensions of purpose in life, self-acceptance and personal growth.

CONCLUSIONS

This study presents a twin analysis of PWB measured by the SPWB dimensions; it was found that both genes and non-shared environment play a role in individual differences. The genetic and non-shared environmental correlations between SPWB dimensions suggest that common underlying genetic and non-shared environmental factors influence the expression of the different facets of PWB.

The Cognitive Differentiation-Integration Effort Hypothesis: A Synthesis between the Fitness Indicator and Life History Models of Human Intelligence

This article presents a potential synthesis between the fitness indicator and life history models of human intelligence through consideration of the phenomena of ability differentiation and integration. The cognitive differentiation-integration effort hypothesis proposes that these effects result from a life history tradeoff between cognitive integration effort, a mating effort component associated with strengthening the positive manifold amongst abilities; and cognitive differentiation effort, a somatic effort component associated with the cultivation of specific abilities. This represents one of two largely independent sources of genetic variance in intelligence; the other is mediated by general fitness and mutation load and is associated with individual differences in levels of ‘genetic g‘. These two sources (along with a common source of environmental variance) combine to give rise to a variety of cognitive phenotypes characterized by different combinations of high or low levels of ‘genetic g‘ and cognitive specialism or generalism. Fundamental to this model is the assumption that measures of life history speed ( K) and g are essentially independent, which is demonstrated via meta-analysis of 10 studies reporting correlations between the variables (ρ = .023, ns, n = 2056). The implications of the model are discussed in an evolutionary, ecological, and developmental context. Seven key predictions are made in the discussion which if tested could provide definitive evidence for the hypothesis.

Polymorphism of the tryptophan hydroxylase 2 (TPH2) gene is associated with chimpanzee neuroticism

In the brain, serotonin production is controlled by tryptophan hydroxylase 2 (TPH2), a genotype. Previous studies found that mutations on the TPH2 locus in humans were associated with depression and studies of mice and studies of rhesus macaques have shown that the TPH2 locus was involved with aggressive behavior. We previously reported a functional single nucleotide polymorphism (SNP) in the form of an amino acid substitution, Q468R, in the chimpanzee TPH2 gene coding region. In the present study we tested whether this SNP was associated with neuroticism in captive and wild-born chimpanzees living in Japan and Guinea, respectively. Even after correcting for multiple tests (Bonferroni p = 0.05/6 = 0.008), Q468R was significantly related to higher neuroticism (β = 0.372, p = 0.005). This study is the first to identify a genotype linked to a personality trait in chimpanzees. In light of the prior studies on humans, mice, and rhesus macaques, these findings suggest that the relationship between neuroticism and TPH2 has deep phylogenetic roots.

Personality assessment in snow leopards (Uncia uncia)

Knowledge of individual personality is a useful tool in animal husbandry and can be used effectively to improve welfare. This study assessed personality in snow leopards (Uncia uncia) by examining their reactions to six novel objects and comparing them to personality assessments based on a survey completed by zookeepers. The objectives were to determine whether these methods could detect differences in personality, including age and sex differences, and to assess whether the two methods yielded comparable results. Both keeper assessments and novel object tests identified age, sex, and individual differences in snow leopards. Five dimensions of personality were found based on keepers' ratings: Active/Vigilant, Curious/Playful, Calm/Self-Assured, Timid/Anxious, and Friendly to Humans. The dimension Active/Vigilant was significantly positively correlated with the number of visits to the object, time spent locomoting, and time spent in exploratory behaviors. Curious/Playful was significantly positively correlated with the number of visits to the object, time spent locomoting, and time spent in exploratory behaviors. However, other dimensions (Calm/Self-Assured, Friendly to Humans, and Timid/Anxious) did not correlate with novel-object test variables and possible explanations for this are discussed. Thus, some of the traits and behaviors were correlated between assessment methods, showing the novel-object test to be useful in assessing an animal's personality should a keeper be unable to, or to support a keeper's assessment.

Personality in nonhuman primates: a review and evaluation of past research

Scientific reports of personality in nonhuman primates are now appearing with increasing frequency across a wide range of disciplines, including psychology, anthropology, endocrinology, and zoo management. To identify general patterns of research and summarize the major findings to date, we present a comprehensive review of the literature, allowing us to pinpoint the major gaps in knowledge and determine what research challenges lay ahead. An exhaustive search of five scientific databases identified 210 relevant research reports. These articles began to appear in the 1930s, but it was not until the 1980s that research on primate personality began to gather pace, with more than 100 articles published in the last decade. Our analyses of the literature indicate that some domains (e.g., sex, age, rearing conditions) are more evenly represented in the literature than are others (e.g., species, research location). Studies examining personality structure (e.g., with factor analysis) have identified personality dimensions that can be divided into 14 broad categories, with Sociability, Confidence/Aggression, and Fearfulness receiving the most research attention. Analyses of the findings pertaining to inter-rater agreement, internal consistency, test-retest reliability, generally support not only the reliability of primate personality ratings scales but also point to the need for more psychometric studies and greater consistency in how the analyses are reported. When measured at the level of broad dimensions, Extraversion and Dominance generally demonstrated the highest levels of inter-rater reliability, with weaker findings for the dimensions of Agreeableness, Emotionality, and Conscientiousness. Few studies provided data with regard to convergent and discriminant validity; Excitability and Dominance demonstrated the strongest validity coefficients when validated against relevant behavioral criterion measures. Overall, the validity data present a somewhat mixed picture, suggesting that high levels of validity are attainable, but by no means guaranteed. Discussion focuses on delineating major theoretical and empirical questions facing research and practice in primate personality.