Paul Irwing

Sex differences in means and variability on the progressive matrices in university students : A meta-analysis

A meta-analysis is presented of 22 studies of sex differences in university students of means and variances on the Progressive Matrices. The results disconfirm the frequent assertion that there is no sex difference in the mean but that males have greater variability. To the contrary, the results showed that males obtained a higher mean than females by between .22d and .33d, the equivalent of 3.3 and 5.0 IQ conventional points, respectively. In the 8 studies of the SPM for which standard deviations were available, females showed significantly greater variability (F(882,656) = 1.20, p < .02), whilst in the 10 studies of the APM there was no significant difference in variability (F(3344,5660) = 1.00, p > .05).

A general factor of personality from multitrait-multimethod data and cross-national twins

In three studies, a General Factor of Personality (GFP) was found to occupy the apex of the hierarchical structure. In Study 1, a GFP emerged independent of method variance and accounted for 54% of the reliable variance in a multitrait-multimethod assessment of 391 Italian high school students that used self-, teacher-, and parent-ratings on the Big Five Questionnaire - Children. In Study 2, a GFP was found in the seven dimensions of Cloningers Temperament and Character Inventory as well as the Big Five of the NEO PI-R, with the GFPtci correlating r = .72 with the GFPneo. These results indicate that the GFP is practically the same in both test batteries, and its existence does not depend on being extracted using the Big Five model. The GFP accounted for 22% of the total variance in these trait measures, which were assessed in 651 pairs of 14- to 30-year-old Japanese twins. In Study 3, a GFP accounted for 32% of the total variance in nine scales derived from the NEO PI-R, the Humor Styles Questionnaire, and the Trait Emotional Intelligence Questionnaire assessed in 386 pairs of 18- to 74-year-old Canadian and U.S. twins. The GFP was found to be 50% heritable with high scores indicating openness, conscientiousness, sociability, agreeableness, emotional stability, good humor and emotional intelligence. The possible evolutionary origins of the GFP are discussed.

The Distance Between Mars and Venus: Measuring Global Sex Differences in Personality

Background Sex differences in personality are believed to be comparatively small. However, research in this area has suffered from significant methodological limitations. We advance a set of guidelines for overcoming those limitations: (a) measure personality with a higher resolution than that afforded by the Big Five; (b) estimate sex differences on latent factors; and (c) assess global sex differences with multivariate effect sizes. We then apply these guidelines to a large, representative adult sample, and obtain what is presently the best estimate of global sex differences in personality. Methodology/Principal Findings Personality measures were obtained from a large US sample (N = 10,261) with the 16PF Questionnaire. Multigroup latent variable modeling was used to estimate sex differences on individual personality dimensions, which were then aggregated to yield a multivariate effect size (Mahalanobis D). We found a global effect size D = 2.71, corresponding to an overlap of only 10% between the male and female distributions. Even excluding the factor showing the largest univariate ES, the global effect size was D = 1.71 (24% overlap). These are extremely large differences by psychological standards. Significance The idea that there are only minor differences between the personality profiles of males and females should be rejected as based on inadequate methodology.

Intergroup contact, friendship quality and political attitudes in integrated and segregated schools in Northern Ireland.

BACKGROUND This study examines the effects of integrated and segregated schooling on Northern Irish childrens self-reported contact and friendship with members of the other denominational group in school and community settings. AIM To assess the effects of cross group friendships and cross group contacts in school and outside school on childrens political attitudes. SAMPLE A cross-sectional design was employed with 1732 children being assessed at three age levels 11,12 & 14 years in eight-matched integrated, maintained (Catholic) and controlled (Protestant) schools. METHOD Lisrel modelling was used to investigate the interrelationships among cross group friendship quality, cross group contacts in school and outside school and childrens political attitudes. RESULTS Intergroup contact within and outside school was reported frequently in integrated schools but only occasionally in segregated schools. Modelling revealed that cross group contacts in school and outside school were both associated with less extreme political attitudes. Friendship quality with cross group members had no significant effects on political attitudes. CONCLUSIONS The results provide support for educating Protestants and Catholics together as a means of moderating attitudes and creating cross-community friendships in a divided society.

Intelligence:Is There a Sex Difference in IQ Scores?

Arising from: S. Blinkhorn Nature 438, 31-32 (2005); Blinkhorn replies.Steve Blinkhorncriticizes our study of samples of university students, in which we found that the average IQ of men is 4.6 points higher than that of women, as measured by the Progressive (or Ravens) Matrices. He maintains that there is a negligible sex difference in adult intelligence. We believe that the principal error of Blinkhorns criticism is that he does not consider our result in the context of several other studies showing that adult males have an IQ advantage of around 4–6 IQ points.

A General Factor of Personality (GFP) in the Personality Disorders: Three Studies of the Dimensional Assessment of Personality Pathology — Basic Questionnaire (DAPP-BQ)

We used structural equation modeling to test the hypothesis that a General Factor of Personality (GFP) occupies the apex of the hierarchy of personality disorders in three validation samples of the Dimensional Assessment of Personality Pathology - Basic Questionnaire (DAPP-BQ). In a general population sample (N = 942), we found a GFP explained 34% of the variance in four first-order factors and 33% of the variance in all 18 scales. In a twin sample (N = 1,346), a GFP explained 35% of the variance in four first-order factors and 34% of the variance in all 18 scales. In a clinical sample (N = 656), a GFP explained 34% of the variance in four first-order factors and 30% of the variance in all 18 scales.

Parental and School Effects on Children's Political Attitudes in Northern Ireland.

BACKGROUND Recent research has suggested that intergroup contacts with out-group members can both reduce prejudice and is associated with attitude change. AIM This study extends prior work in Northern Ireland to examine parental and schooling effects on childrens attitudes in a post-conflict environment. SAMPLE A large-scale cross-sectional survey of secondary schoolchildren (N=1,732) and their parents (N=800) in Northern Ireland assessed the effects of in-school and out-of-school intergroup contacts on intergroup attitudes. METHOD Multivariate analysis of variance was employed to examine associations between childrens political attitudes and parental, group membership, school, and contact variables. CONCLUSIONS The results suggest that parental attitudes, group membership, and cross-group contacts explain the majority of variance (58%) in childrens political attitudes. The findings provide a comprehensive account of the factors that influence childrens political attitudes within a deeply divided society and offer teachers and educationalists a way to improve community relations in a segregated society.

Leader dark traits, workplace bullying, and employee depression: Exploring mediation and the role of the dark core.

A growing body of empirical evidence now supports a negative association between dark traits in leaders and the psychological health of employees. To date, such investigations have mostly focused on psychopathy, nonspecific measures of psychological wellbeing, and have not considered the mechanisms through which these relationships might operate. In the current study (N = 508), we utilized other-ratings of personality (employees rated leaders’ personality), psychometrically robust measures, and sophisticated modeling techniques, to examine whether the effects of leaders’ levels of narcissism and psychopathy on employee depression are mediated by workplace bullying. Structural equation models provided clear evidence to suggest that employee perceptions of both leader narcissism and psychopathy are associated with increased workplace bullying (25.8% and 41.0% variance explained, respectively) and that workplace bullying fully mediates the effect of leader narcissism and psychopathy on employee depression (21.5% and 20.8% variance explained, respectively). However, when psychopathy and narcissism were modeled concurrently, narcissism did not explain any variance in bullying, suggesting that it is the overlap between psychopathy and narcissism, namely, the “dark core,” which primarily accounts for the observed effects. We examined this assertion empirically and explored the unique effects of the subfactors of psychopathy.