Disentangling periodic and aperiodic resting EEG correlates of personality.

Previous studies of resting electroencephalography (EEG) correlates of personality traits have conflated periodic and aperiodic sources of EEG signals. Because these are associated with different underlying neural dynamics, disentangling them can avoid measurement confounds and clarify findings. In a large sample (n = 300), we investigated how disentangling these activities impacts findings related to two research programs within personality neuroscience. In Study 1 we examined associations between Extraversion and two putative markers of reward sensitivity-Left Frontal Alpha asymmetry (LFA) and Frontal-Posterior Theta (FPT). In Study 2 we used machine learning to predict personality trait scores from resting EEG. In both studies, power within each EEG frequency bin was quantified as both total power and separate contributions of periodic and aperiodic activity. In Study 1, total power LFA and FPT correlated negatively with Extraversion (r ∼ -0.14), but there was no relation when LFA and FPT were derived only from periodic activity. In Study 2, all Big Five traits could be decoded from periodic power (r ∼ 0.20), and Agreeableness could also be decoded from total power and from aperiodic indices. Taken together, these results show how separation of periodic and aperiodic activity in resting EEG may clarify findings in personality neuroscience. Disentangling these signals allows for more reliable findings relating to periodic EEG markers of personality, and highlights novel aperiodic markers to be explored in future research.

Why moral psychology needs personality psychology.

People vary in how they perceive, think about, and respond to moral issues. Clearly, we cannot fully understand the psychology of morality without accounting for individual differences in moral functioning. But decades of neglect of and explicit skepticism toward such individual differences has resulted in a lack of integration between moral psychology and personality psychology-the study of psychological differences between people. In recent years, these barriers to progress have started to break down. This special issue aims to celebrate and further increase the visibility of the personality psychology of morality. Here, we introduce the articles in this special issue by highlighting some important contributions a personality-based perspective has to offer moral psychology-particularly in comparison to the currently prominent social psychological approach. We show that personality psychology is well-placed to (a) contribute toward a rigorous empirical foundation for moral psychology, (b) tackle the conceptualization and assessment of stable moral tendencies, (c) assess the predictive validity of moral traits in relation to consequential outcomes, (d) uncover the mechanisms underlying individual differences in moral judgments and behavior, and (e) provide insights into moral development. For these reasons, we believe that moral psychology needs personality psychology to reach its full scholarly potential.

Differential responses to ethical vegetarian appeals: Exploring the role of traits, beliefs, and motives.

OBJECTIVE: This research examines differential responses to ethical vegetarian appeals as a fuction of individuals' personalities. BACKGROUND: Ethical vegetarian appeals are persuasive messages promoting the adoption of a plant-based diet on moral grounds. Individuals may vary in their receptivity to such appeals, depending on their morally relevant traits (e.g., agreeableness), beliefs (e.g., speciesism), and motives (e.g., concerns about animal welfare). METHODS: We explored (Study 1, N = 907) and then attempted to confirm (Study 2, N = 980) differential responses to three vegetarian appeals-two highlighting moral concerns (animal welfare, the environment) and a third focusing on individual health (control condition). RESULTS: Both studies revealed several differential effects of our vegetarian appeals on the perceived effectiveness of the appeal and resultant intentions to reduce meat consumption. These mostly consisted of differences in receptivity to appeals focused on animal welfare. However, only one such effect observed in Study 1 was clearly replicated in Study 2: People who more strongly believed that eating meat was "normal" rated the vegetarian appeals focused on animal welfare as less effective. CONCLUSION: Ethical vegetarian appeals may elicit different responses from different people, particularly those focused on animal welfare, depending on how normative one believes meat-eating to be. Such insights can inform behavior change efforts in this area.

Evaluating the effectiveness of vegetarian appeals in daily life: Comparing positive and negative imagery, and gauging differential responses.

Persuasive appeals designed to reduce meat consumption often employ graphic images of the harms perpetuated by eating meat (e.g., cruel factory farming practices). However, because people are motivated to see themselves as moral, appeals that highlight omnivores' moral failings might be resisted or even backfire. Furthermore, individuals differ in ways that may influence their motivations and attitudes toward animals and meat-eating, and their responses to these appeals. Thus, in a two-week intervention study (N = 427), we compared effects of two vegetarian appeals-one employing graphic negative imagery (footage of factory farming cruelty), the other employing positive imagery (footage from farmed animal sanctuaries)-on daily meat consumption and related affects and cognitions. We also examined several personality traits and other individual differences that may confer differential effects of these appeals. Although neither appeal significantly reduced meat consumption, both the positive and negative appeal increased intentions to eat less meat, and led to more negative affect and cognition when eating meat. Moreover, several individual difference variables moderated the effects of these appeals on actual and intended meat consumption. Findings are discussed in relation to the difficulty of changing morally troublesome behaviour, and the use of graphic appeals despite their unclear impact on behaviour.

Does openness/intellect predict sensitivity to the reward value of information?

A recent theory proposes that the personality trait openness/intellect is underpinned by differential sensitivity to the reward value of information. This theory draws on evidence that midbrain dopamine neurons respond to unpredicted information gain, mirroring their responses to unpredicted primary rewards. Using a choice task modelled on this seminal work (Experiment 1, N = 139, 69% female), we examined the relation between openness/intellect and willingness to pay for non-instrumental information (i.e., information with no secondary utility). We also assessed whether any such relation was moderated by the dopamine D2 receptor antagonist sulpiride (Experiment 2, N = 164, 100% male). Unexpectedly, most measures of openness/intellect were unrelated to costly information preference in both experiments, and some predicted a decreased willingness to incur a cost for information. In Experiment 2, this cost-dependent association between openness/intellect and information valuation appeared in the placebo condition but not under sulpiride. In addition, participants were more willing to pay for moderately costly information under sulpiride compared to placebo, consistent with a dopaminergic basis to information valuation. Potential refinements to the information valuation theory of openness/intellect are discussed in the light of these and other emerging findings.

Personality and moral judgment: Curious consequentialists and polite deontologists.

OBJECTIVE: How does our personality relate to the ways in which we judge right from wrong? Drawing on influential theories of moral judgment, we identify candidate traits that may be linked with inclinations toward (a) consequentialist judgments (i.e., those based on the outcomes of an action) and (b) deontological judgments (i.e., those based on the alignment of an action with particular moral rules). METHOD: Across two studies (total N = 843) we examined domains and aspects of the Big Five in relation to inclinations toward consequentialist and deontological judgments. RESULTS: In both studies, we found a unique association between intellect (curiosity, cognitive engagement) and consequentialist inclinations, in line with the view that deliberative cognitive processes drive such inclinations. We also found a consistent unique association between politeness (respectfulness, etiquette) and deontological inclinations, in line with the view that norm-adherence drives such inclinations. Neither study yielded a significant unique relation between deontological inclinations and compassion (sympathy, empathic concern)-or any other emotion-infused trait (e.g., Neuroticism)-as would be expected based on emotion-centered views of deontological moral judgment. CONCLUSIONS: These findings have implications for theories of moral judgment, and reveal how our personality may guide our approach to questions of ethics and morality.

Who gives a veg? Relations between personality and Vegetarianism/Veganism.

With rates of vegetarianism and veganism (i.e., veg*nism) rising around the world, a growing body of research has begun to explore psychological characteristics that distinguish vegetarians and vegans from omnivores. However, relatively few studies have examined how veg*nism is related to differences in basic personality traits such as the "Big Five", with those that have tending to yield conflicting results. Moreover, none of these studies have examined personality at the lower levels of the personality trait hierarchy (i.e., aspects and facets of the Big Five). Thus, we sought to clarify how personality traits are related to veg*nism. In Study 1, comprising two samples (S1a: N = 797, S1b: N = 1534), participants were categorised as Veg*n vs Restricted-omnivore vs Omnivore, and completed personality questionnaires at the domain and aspect levels of the Big Five. In Study 2, participants (N = 562) completed both categorical and continuous measures of veg*nism, along with personality questionnaires at the domain, aspect, and facet levels. Across both studies, we found that people who scored higher on traits within the openness/intellect and agreeableness domains most consistently reported higher levels of veg*nism. Patterns in the data also suggested that the relation between personality and veg*nism might depend on the way veg*nism is measured. Theoretical and practical implications of these findings are discussed.

Using the Big Five Aspect Scales to translate between the HEXACO and Big Five personality models.

OBJECTIVE: The extensive use of two diverging personality taxonomies (the Big Five and HEXACO models) in contemporary research creates a need for understanding how traits connect to each other across taxonomies. Previous research has approached this at both a highly general (domain-) level as well as at a highly specific (facet-) level. The present report is the first to use the intermediate (aspect-) level of the Big Five Aspect Scales (BFAS) to understand the connections between the two models. METHOD: We explored these associations in a meta-analysis of four samples drawn from three countries (total N = 1,586). RESULTS: We observed that each HEXACO domain correlated ≥|0.51| with one or more BFAS aspects. Half of the aspects were more strongly associated with HEXACO facets than with HEXACO domains, sometimes markedly so. CONCLUSION: Although many domains, aspects, and facets are similarly represented across the two models, this was not always the case. Researchers seeking to use one model to extend findings built primarily off the other should carefully consider how well represented their traits of interest are in the other assessment. Psychology instructors are encouraged to use the BFAS to illustrate the subtler distinctions between the Big Five and HEXACO models.

Unique Associations Between Big Five Personality Aspects and Multiple Dimensions of Well-Being.

OBJECTIVE: Personality traits are associated with well-being, but the precise correlates vary across well-being dimensions and within each Big Five domain. This study is the first to examine the unique associations between the Big Five aspects (rather than facets) and multiple well-being dimensions. METHOD: Two samples of U.S. participants (total N = 706; Mage = 36.17; 54% female) recruited via Amazon's Mechanical Turk completed measures of the Big Five aspects and subjective, psychological, and PERMA well-being. RESULTS: One aspect within each domain was more strongly associated with well-being variables. Enthusiasm and Withdrawal were strongly associated with a broad range of well-being variables, but other aspects of personality also had idiosyncratic associations with distinct forms of positive functioning (e.g., Compassion with positive relationships, Industriousness with accomplishment, and Intellect with personal growth). CONCLUSIONS: An aspect-level analysis provides an optimal (i.e., parsimonious yet sufficiently comprehensive) framework for describing the relation between personality traits and multiple ways of thriving in life.

Individual Differences in Good Manners Rather Than Compassion Predict Fair Allocations of Wealth in the Dictator Game.

One of the most common tools for studying pro-sociality is the dictator game, in which allocations to one's partner are often described in terms of altruism. However, the motivations driving these allocations may represent either emotional concern for others (compassion), adherence to social norms regarding fairness (politeness), or both. In this article, we apply personality psychology to the study of behavior in the dictator game, in which we examine the discriminant validity of distinct pro-social constructs from the Big Five and HEXACO models in relation to allocations of wealth. Across four studies (Study 1: N = 192; Study 2: N = 212; Study 3: N = 304; Study 4: N = 90) utilizing both hypothetical and incentivized designs, we found that the politeness-but not compassion-aspect of Big Five Agreeableness, as well as HEXACO Honesty-Humility, uniquely predicted dictator allocations within their respective personality models. These findings contribute to a growing literature indicating that the standard dictator game measures "good manners" or adherence to norms concerning fairness, rather than pure emotional concern or compassionate motives, and have important implications for how this paradigm is used and interpreted in psychological research.

The Role of Interpersonal Traits in Social Decision Making: Exploring Sources of Behavioral Heterogeneity in Economic Games.

Economic games are well-established experimental paradigms for modeling social decision making. A large body of literature has pointed to the heterogeneity of behavior within many of these games, which might be partly explained by broad interpersonal trait dispositions. Using the Big Five and HEXACO (Honesty-Humility, Emotionality, eXtraversion, Agreeableness, Conscientiousness, Openness to Experience) personality frameworks, we review the role of personality in two main classes of economic games: social dilemmas and bargaining games. This reveals an emerging role for Big Five agreeableness in promoting cooperative, egalitarian, and altruistic behaviors across several games, consistent with its core characteristic of maintaining harmonious interpersonal relations. The role for extraversion is less clear, which may reflect the divergent effects of its underlying agentic and affiliative motivational components. In addition, HEXACO honesty-humility and agreeableness may capture distinct aspects of prosocial behavior outside the bounds of the Five-Factor Model. Important considerations and directions for future studies are discussed within the emerging personality-economics interface.

Clarifying the Relation Between Extraversion and Positive Affect.

This article clarifies two sources of ambiguity surrounding the relation between extraversion and positive affect. First, positive affect is defined differently across major models of the structure of affect. Second, no previous research has examined potentially diverging associations of lower-order aspects of extraversion (i.e., assertiveness and enthusiasm) with positive affect. Australian (Study 1: N = 437, 78% female, Mage = 20.41) and American (Study 2: N = 262, 39% female, Mage = 33.86) participants completed multiple measures of extraversion and positive affect. Correlations were employed to examine relations among these measures. In both studies, extraversion was most clearly associated with positive affect as conceptualized within a major factor model of affect-specifically, as positive activation (Watson & Tellegen, 1985)-rather than the valence-based conceptualization of positive affect provided by a circumplex model of affect (Russell, 1980). This was also the case for the assertiveness and enthusiasm aspects of extraversion. Our findings clarify the nature of the positive affective component of extraversion, which is best described in terms of both positive valence and high activation.

Factor structure and construct validity of the temporal experience of pleasure scales.

Feelings of pleasure felt in the moment of goal attainment (consummatory pleasure) are thought to be dissociable from feelings of desire connected with the motivated approach of goals (anticipatory pleasure). The Temporal Experience of Pleasure Scales (TEPS; Gard, Gard, Kring, & John, 2006) was developed to assess individual differences in these distinct processes. Recently, an independent evaluation of the psychometric characteristics of a Chinese-translated TEPS suggested a more complex factor structure (Chan et al., 2012). This study aimed to reexamine the factor structure and convergent and divergent validity of the TEPS in two previously unexamined multiethnic samples. University students in the United Kingdom (N = 294) completed the TEPS and university students in Australia (N = 295) completed the TEPS as well as a battery of conceptually related questionnaires. A confirmatory factor analysis of Gard et al.'s (2006) 2-factor model produced inadequate fit, which model-modification indexes suggested might be due to item cross-loadings. This issue was examined further using an exploratory factor analysis, which revealed a clear 2-factor solution despite cross-loadings among some items. Finally, mixed evidence for convergent-divergent validity was obtained, in terms of relationships between the TEPS and measures of anhedonia, approach-motivation, and positive emotion.

Characterising Insistence on Sameness and Circumscribed Interests: A Qualitative Study of Parent Perspectives.

Manifestations of insistence on sameness (IS) and circumscribed interests (CI) are complex, with individuals varying considerably, not only in the types of behaviours they express, but also in terms of a behaviour's frequency, intensity, trajectory, adaptive benefits, and impacts. However, current quantitative RRB instruments capture only certain aspects of these behaviours (e.g., mostly frequency or general "severity"). Thus, the current study utilised a semi-structured caregiver interview to provide an in-depth, qualitative characterization of different aspects of IS and CI presentation. Caregivers of 27 autistic children and adolescents displaying IS and/or CI behaviours (3-16 years; 18 males; 9 females) participated in a semi-structured interview. Responses were analysed using thematic framework analysis. Framework analysis identified nine different aspects of IS and CI presentation: (1) intensity, (2) frequency, (3) emergence of behaviour, (4) changes over time, (5) day-to-day fluctuations, (6) purpose/adaptive benefit, (7) experiences of distress, (8) challenges for the individual, their family, and their socialisation, and (9) management strategies and their effectiveness. Autistic children and adolescents were reported to vary greatly on each of these dimensions. Findings demonstrate the complexity of IS and CI presentations and highlight the need for more comprehensive quantitative assessments that independently assess the frequency, intensity, and impact of behaviours. Further, findings reported here emphasize the need for ecologically valid measures that assess the contexts in which these behaviours occur and how their presentations can change within and across days.

Psychological well-being in Europe after the outbreak of war in Ukraine.

The Russian invasion of Ukraine on February 24, 2022, has had devastating effects on the Ukrainian population and the global economy, environment, and political order. However, little is known about the psychological states surrounding the outbreak of war, particularly the mental well-being of individuals outside Ukraine. Here, we present a longitudinal experience-sampling study of a convenience sample from 17 European countries (total participants = 1,341, total assessments = 44,894, countries with >100 participants = 5) that allows us to track well-being levels across countries during the weeks surrounding the outbreak of war. Our data show a significant decline in well-being on the day of the Russian invasion. Recovery over the following weeks was associated with an individual's personality but was not statistically significantly associated with their age, gender, subjective social status, and political orientation. In general, well-being was lower on days when the war was more salient on social media. Our results demonstrate the need to consider the psychological implications of the Russo-Ukrainian war next to its humanitarian, economic, and ecological consequences.

Personality traits beyond Neuroticism predict post-concussive symptomatology in the post-acute period after mild traumatic brain injury in premorbidly healthy adults.

There is growing evidence that an individual's personality traits are related to post-concussion symptomatology beyond the acute period after mild traumatic brain injury (mTBI). Few studies, however, have analyzed this impact beyond the personality trait of Neuroticism. We examined the impact of personality traits on post-concussion symptoms (PCS) by measuring the Big Five personality domains and their lower-order aspects in 87 pre-morbidly healthy participants assessed 6-12 weeks post-mTBI (n = 53) or physical trauma (n = 34). As expected, Neuroticism predicted PCS endorsement in both groups. Conscientiousness and Openness/intellect were predictive of lower PCS endorsement, but only in the mTBI group. Withdrawal, one aspect within the Neuroticism domain, independently predicted PCS endorsement in the mTBI group; the remaining Neuroticism aspect, Volatility, did not predict PCS endorsement in either group. These findings suggest that individuals high in Neuroticism are more likely to report PCS following mTBI and that this relationship is driven by susceptibility to depression/anxiety symptoms (Withdrawal aspect) rather than irritability (Volatility aspect). Further, they suggest that the current focus on the relationship between Neuroticism and PCS reporting in individuals with mTBI should be broadened to include other personality domains, such as Conscientiousness and Openness/intellect.

Characterizing subdomains of insistence on sameness in autistic youth.

Insistence on sameness (IS) encompasses a range of behavioral patterns, including resistance to change, routines, and ritualized behaviors, that can be present across social and non-social contexts. Given the breadth of behaviors encompassed by IS, it is important to determine whether this domain is best conceptualized and measured as uni- or a multi-dimensional construct. Therefore, the current study aimed to characterize the structure of IS and explore potentially distinct of patterns of associations between identified IS factors and relevant correlates, including age, sex, IQ, anxiety, social abilities, emotional and behavioral dysregulation, and sensory hypersensitivity. Exploratory graph analysis was conducted using the dimensional assessment of restricted and repetitive behaviors to examine the structure of IS in a sample 1892 autistic youth (Mage = 10.82, SDage = 4.14; range: 3-18 years; 420 females) recruited from the Simons Foundation Powering Autism Research for Knowledge cohort. Three distinct IS subdomains labeled as IS-Ritualistic/sameness, IS-Routines, and IS-Others (referring to IS behaviors during interactions with others) were identified. Generalized additive models demonstrated that each of the IS subdomains showed a unique pattern of association with key variables. More specifically, while sensory hypersensitivity was significantly associated with IS-Ritualistic/sameness and IS-Routines, it was not associated with IS-Others. Further, while emotional dysregulation was a unique predictor of IS-Ritualistic/sameness (but not IS-Routines or IS-Others), social interaction abilities were a unique predictor of IS-Routines (but not IS-Ritualistic/sameness or IS-Others). Current findings provide preliminary evidence that the IS may encompass several distinct subdomains.

Characterizing restricted and unusual interests in autistic youth.

A broad range of interests characterized by unusual content and/or intensity, labeled as circumscribed interests (CI), are a core diagnostic feature of autism. Recent evidence suggests that a distinction can be drawn between interests that, although characterized by unusually high intensity and/or inflexibility, are otherwise common in terms of their content (e.g., an interest in movies or animals), labeled as restricted interests (RI), and interests that are generally not salient outside of autism (e.g., an interest in traffic lights or categorization), labeled as unusual interests (UI). The current study aimed to further characterize RI and UI by exploring their association with age, sex, IQ, and social motivation, as well as to examine differences in the adaptive benefits and negative impacts of these two subdomains. Parents of 1892 autistic children and adolescents (Mage  = 10.82, SDage  = 4.14; 420 females) completed an online survey including the Dimensional Assessment of Restricted and Repetitive Behaviors and the Social Communication Questionnaire. Both RI and UI were found to be highly frequent. Sex-based differences were observed in the content, but not intensity, of CI such that females were more likely to show interests with a social component. Finally, RI and UI showed distinct patterns of association with age, sex, IQ, and social motivation, as well as metrics of adaptive benefits and negative impacts. Findings afford a more nuanced understanding of sex-based differences in CI and, crucially, provide preliminary evidence that RI and UI represent distinct constructs that should be studied independently in future research.

Profiles of circumscribed interests in autistic youth.

Circumscribed interests (CI) encompass a range of different interests and related behaviors that can be characterized by either a high intensity but otherwise usual topic [referred to as restricted interests (RI)] or by a focus on topics that are not salient outside of autism [referred to as unusual interests (UI)]. Previous research has suggested that there is pronounced variability across individuals in terms of the endorsement of different interests, however, this variability has not been quantified using formal subtyping approaches. Therefore, using Latent Profile Analysis in a sample of 1,892 autistic youth (Mage = 10.82, SDage = 4.14; 420 females), this study aimed to identify subgroups based on the RU and UI profiles. Three profiles of autistic individuals were identified. They were characterized as Low CI, Predominantly RI, and Predominantly UI. Importantly, profiles differed on several key demographic and clinical variables, including age, sex composition, IQ, language level, social and communication abilities, anxiety, and obsessive-compulsive behaviors. Although replication across other samples is needed, the profiles identified in this study are potentially promising for future research given their distinct profiles of RI and UI and unique patterns of associations with key cognitive and clinical variables. Therefore, this study represents an important initial step towards more individualized assessment and support for diverse presentations of CI in autistic youth.

Evaluating the Big Five as an organizing framework for commonly used psychological trait scales.

The Big Five is often represented as an effective taxonomy of psychological traits, yet little research has empirically examined whether stand-alone assessments of psychological traits can be located within the Big Five framework. Meanwhile, construct proliferation has created difficulty navigating the resulting landscape. In the present research, we developed criteria for assessing whether the Big Five provides a comprehensive organizing framework for psychological trait scales and evaluated this question across three samples (Total N = 1,039). Study 1 revealed that 83% of an author-identified collection of scales (e.g., Self-Esteem, Grit, etc.) were as related to the Big Five as at least four of 30 Big Five facets, and Study 2 found that 71% of scales selected based on citation counts passed the same criterion. Several scales had strikingly large links at the Big Five facet level, registering correlations with individual Big Five facets exceeding .9. We conclude that the Big Five can indeed serve as an organizing framework for a sizable majority of stand-alone psychological trait scales and that many of these scales could reasonably be labeled as facets of the Big Five. We suggest an integrative pluralism approach, where reliable, valid scales are located within the Big Five and pertinent Big Five research is considered in all research using trait scales readily located within the Big Five. By adopting such an approach, construct proliferation may be abated and it would become easier to integrate findings from disparate fields. (PsycInfo Database Record (c) 2022 APA, all rights reserved).