Experimental analysis of individual differences and personality

In psychological studies individual differences that result in variability in data and thus mask the effects under investigation have been reduced or eliminated in two ways: (1) through the use of large numbers of subjects and statistical manipulations, or (2) through extensive and controlled studies of individual subjects. The latter, behavior-analytic, method is scientifically better because it permits identification of the variables that result in individual differences. This paper advocates the direct study of individual differences and personality rather than indirect study through experimental control procedures. Some data are presented showing that individual differences in response patterns have orderly characteristics. Extension of the experimental analysis of behavior to the study of individual differences and personality is likely to be important both scientifically and for the future growth of behavior analysis.     

Gender differences in implicit and explicit personality traits

This article investigates gender differences in implicit and explicit measures of the Big Five traits of personality. In a high-powered study (N = 14,348), we replicated previous research showing that women report higher levels of Agreeableness, Conscientiousness, Extraversion and Neuroticism. For implicit measures, gender differences were much smaller for all, and opposite in sign for Extraversion. Somewhat higher levels of implicit Neuroticism and Agreeableness were observed in women, and somewhat higher levels of implicit Extraversion and Openness were observed in men. There was no gender difference in implicit Conscientiousness. A possible explanation is that explicit self-concepts partly reflect social norms and self-expectations about gender roles, while implicit self-concepts may mostly reflect self-related experiences.     

Individual differences in personality and face identification

Unfamiliar face identification is characterised by substantial variation between individual observers, but the cause of this variation is largely unknown. This study investigated whether individual differences in face identification are linked to an observer's personality, by combining performance on an established face-matching test with two in-depth personality assessments (the 16PF5 and the NEO-PI-R). The face test revealed a broad distribution in identification ability, but associations between face perception and personality were found only in female observers. In this group, correct face identifications related to low anxiety, low tension, and high emotional stability. These results suggest that associations between personality and face perception are limited, and are confined to anxiety and facets of neuroticism.     

人格差异性的进化心理学解释

进化心理学一直热衷于人格共同性的探讨,但一些研究者也认为应该关注人格差异性,因为共同性和差异性是人格必不可分的两面。对人格差异性的进化解释比较成熟的有三种：生活历史理论、基因多样性理论和代价信号理论。生活历史理论认为是不同的环境(稳定和不稳定),造成了不同的生活历史策略(K策略和R策略),人格特质差异是这些策略的进化产物。基因多样性理论主要从基因突变和平衡选择的角度来解释人格差异性。前者强调突变基因的不可避免性引发了个性差异的存在和发展;后者强调概率的调节作用,解释了不同人格特质之所以能够并行存在的原因。代价信号理论则认为是个体拥有的先天禀赋或者资源差距导致其传递信号的能力差异,从而选择了不同的行为策略。未来研究需要加大遗传学、神经科学等方面的力度,以及研究范式的创新。     

At the interface of social cognition and psychometrics: Manipulating the sex of the reference class modulates sex differences in personality traits

Psychometric surveys suggest that sex differences in personality are minimal. Herein, we argue that (a) the mind is likely biased toward assessing oneself relative to same-sex others, and (b) this bias may affect the measurement of sex differences in personality. In support of this, an experiment demonstrates modulation of sex differences on the HEXACO facets by manipulating the sex of the “reference class”—the group of people subjects compare themselves to when making self-assessments on survey items. Although patterns varied across traits, sex differences were relatively small in the “unspecified” and “same-sex” reference class conditions—but substantially larger in the “opposite-sex” condition. These findings point to a same-sex comparison bias that may impact the measurement of sex differences in personality.     

Realistic affective forecasting: The role of personality

Affective forecasting often drives decision-making. Although affective forecasting research has often focused on identifying sources of error at the event level, the present investigation draws upon the “realistic paradigm” in seeking to identify factors that similarly influence predicted and actual emotions, explaining their concordance across individuals. We hypothesised that the personality traits neuroticism and extraversion would account for variation in both predicted and actual emotional reactions to a wide array of stimuli and events (football games, an election, Valentine's Day, birthdays, happy/sad film clips, and an intrusive interview). As hypothesised, individuals who were more introverted and neurotic anticipated, correctly, that they would experience relatively more unpleasant emotional reactions, and those who were more extraverted and less neurotic anticipated, correctly, that they would experience relatively more pleasant emotional reactions. Personality explained 30% of the concordance between predicted and actual emotional reactions. Findings suggest three purported personality processes implicated in affective forecasting, highlight the importance of individual-differences research in this domain, and call for more research on realistic affective forecasts.     

Hormones and personality: Testosterone as a marker of individual differences

Recently, testosterone (T) has been linked to behaviors that are conceptually related to dominance as a personality characteristic. Although evidence for this association is growing, the psychometric properties of T as an individual difference variable have been largely neglected. For T to be considered a biological marker of dispositional dominance it is critical that it demonstrates high test–retest reliability and good convergent and discriminant validity. Two studies tested the temporal stability of salivary T in humans and the relationship between T and traditional measures of personality. Across both studies, test–retest reliability for T was high and comparable to the short-term stability of questionnaire-based and implicitly assessed personality assessment instruments. In being modestly correlated with self-reported dominance, T showed some evidence of convergent validity. In being statistically independent from conceptually unrelated personality constructs (such as Emotional Stability and Openness to Experience) it showed good evidence of discriminant validity. The findings strengthen the psychometric foundation for using T as a hormonal marker of individual differences.     

Predicting the acceptability and likelihood of lying: The interaction of personality with type of lie

The present study investigated the role of individual differences in the perceived acceptability and likelihood of different types of lies. Two-hundred and eighty seven college students completed scales assessing six personality variables (honesty, kindness, assertiveness, approval motivation, self-monitoring, and Machiavellianism) and rated 16 scenarios involving lies told for four different motives (altruistic, conflict avoidance, social acceptance, and self-gain lies). Our central hypothesis that the perceived acceptability and likelihood of lying would be predicted by interactions between personality characteristics of the rater and the type of lie being considered was supported. For each type of lie, a unique set of personality variables significantly predicted lying acceptability and likelihood.     

Cross-sectional age differences in personality: Evidence from nationally representative samples from Switzerland and the United States

Identifying reliable patterns of age differences in personality can help clarify the nature of adult personality development. Previous studies have been limited because many have relied on convenience samples. In this study, we examined age differences in personality in two nationally representative samples, one from Switzerland and one from the United States. The results indicated that Agreeableness and Conscientiousness were positively associated with age, whereas Extraversion was negatively associated with age. However, the magnitude of age differences for Extraversion was much smaller than for Agreeableness and Conscientiousness. Openness showed a more complex trend such that 30- to 34-year-olds scored lower on Openness than younger age groups, whereas older groups scored somewhere in between. Inconsistent age differences were observed for Neuroticism.     

Gender and autistic personality traits predict perspective-taking ability in typical adults

Adopting another’s visual perspective is exceedingly common and may underlie successful social interaction and empathizing with others. The individual differences responsible for success in perspective-taking, however, remain relatively undiscovered. We assessed whether gender and autistic personality traits in normal college student adults predict the ability to adopt another’s visual perspective. In a task differentially recruiting VPT-1 which involves following another’s line of sight, and VPT-2 which involves determining how another may perceive an object differently given their unique perspective (VPT-2), we found effects of both gender and autistic personality traits. Specifically, we demonstrate slowed VPT-2 but not VPT-1 performance in males and females with relatively high ASD-characteristic personality traits; this effect, however was markedly stronger in males than females. Results contribute to knowledge regarding ASD-related personality traits in the general population and the individual differences modulating perspective-taking abilities.     

Taking parent personality and child temperament into account in child language development

Individual differences have become increasingly important in the study of child development and language. However, despite the important role parents play in children’s language, no work has examined how parent personality impacts language development. The current study examines the impact of parent personality as well as child temperament on language development in 460 16- to 30-month-old children and 328 31- to 42-month-old children. Findings from both groups suggest multiple aspects of children’s language abilities are correlated with their parent’s personality. Specifically, parent consciousness, openness, and agreeableness positively correlate with child vocabulary size and other language abilities. Results also replicate and expand research on child temperament and language – child effortful control and surgency were positively correlated, and negative affect negatively correlated with most language abilities even after controlling for parent personality. Critically, parent and child traits appear to impact a child’s language abilities above and beyond well-known predictors of language, such as age.     

Psychopathic personality traits in relational aggression among young adults

Psychopathy is a robust predictor of overt physical aggression that may also be relevant to relational aggression (RA). This study was conducted to investigate the utility of psychopathic personality traits in the prediction of RA in a sample of 291 college students. Hierarchical multiple regression analyses indicated that both primary and secondary psychopathic traits explained additional variance in general/peer and romantic RA beyond physical aggressiveness. Consistent with previous research, no gender differences were found on either form of RA, challenging the popular stereotype of RA as a female behavior. Moreover, psychopathic traits were not differentially predictive of RA by gender or level of physical aggressiveness. Implications of these findings for research and clinical practice are discussed.     

Measurement invariance of personality traits from a five-factor model perspective: multi-group confirmatory factor analyses of the HP5 inventory

Associations between personality and health may be influenced by contextual factors varying across studied cohorts. Moreover, measurement bias related to contextual factors could also influence these associations. Gender and age have been discussed as important contextual factors when studying personality and health outcomes. An examination of measurement invariance across gender and age may therefore be warranted. In the present study, measurement invariance across age and gender was examined for a five-factor model of personality traits in which scales have been included to operationalise lower-order traits related to health-behaviour or health outcomes. Using multi-group confirmatory factor analysis on a population based cohort (n= 5700), all important parameters of the measurement model were found to be invariant. On the basis of this invariant model, hypotheses of mean differences across age and gender in personality traits were tested. These results were discussed in relation to meta-analyses on personality change and gender differences in personality.