How general is the “General Factor of Personality”? Evidence from the Texas Adoption Project

Using data from samples of 300 and 220 adoptive families from the Texas Adoption Project, aspects of generality of a “General Factor of Personality” (GFP) were examined: across different personality inventories, across different levels of analysis (items, scales) within an inventory, across self- and others’ judgments, and across sexes, ages, and generations. Considerable, though not complete, generality was found. The average correlation between GFPs from items and scales of a given inventory was .90; between GFPs from the scales of different inventories was .48. Also examined were the heritability of a GFP, its degree of correlation with a general cognitive factor, and its ability to predict real-life criteria such as educational level, marital stability, and substance abuse.     

Rushton: The great theoretician and his contribution to personality

J. Philippe Rushton has been described as one of the greatest theorists in the field of personality and individual differences and social psychology. His life history theory (Differential K Theory) was said to bring unification to the scientific study of racial differences as Einstein’s theory of relativity unified the field of physics. It was maintained that Rushton’s General Factor of Personality (GFP) meshes with both general intelligence and his Differential K Theory. The present author presented a two-pillar theory of adaptive functioning that has a heavy concentration on Rushton conceptualization.     

No evidence for a General Factor of Personality in the HEXACO Personality Inventory

There have been an increasing number of articles that have speculated on the existence of a General Factor of Personality (GFP) similar to ‘g’ in intelligence research. In this study, I provide evidence that this general factor may be an artifact of the personality instrument used. Specifically, in two samples I show that depending on the type of analysis used there is either no evidence for a GFP in the HEXACO Personality Inventory or the GFP is found to be uncorrelated to GFPs based on Big Five or FFM instruments.     

J.P. Rushton’s contributions to the study of altruism

This essay describes Rushton’s work on altruism over the past 40 years. During his academic career, he changed his theoretical approach from social learning theory to trait theory to sociobiology. My essay includes five sections. The first gives an overview of Rushton’s work on altruism. The second reviews his early work based on social learning theory. His laboratory and naturalistic experiments led him to conclude that altruism could be increased by exposure to models exemplifying the behavior, and that, once engaged in, the behavior could be durable over months and generalizable across situations. The third section discusses his work on the genetic foundation of altruism with social biology including his twin studies of prosocial behaviors using different age groups of both western and Asian samples. He concluded that about 50% of the variance in prosocial behaviors is heritable. The fourth section will describe altruism as part of the general factor of personality, the apex of the personality hierarchy. The last section summarizes my review of Rushton’s work on altruism.     

The general factor of personality: What lies beyond?—II

What remains of the covariance of personality traits after a general factor of personality (GFP) is removed? An earlier analysis based on a US adult community sample was extended to five additional samples, ranging from 739 to 2914 late-adolescent or adult individuals who had completed various personality questionnaires in twin and adoption studies. For the most part, the GFPs were similar. Most of the data sets revealed an additional Conscientiousness/conformity factor, but beyond that there was considerable variation across samples in the supplemental factors obtained.     

How general across inventories is a general factor of personality?

Two recent analyses addressing the generality of a general factor of personality (GFP) across different personality inventories came to markedly different conclusions. By applying the methods used by the one that found a GFP to the data used by the one that did not, it was shown that a substantial GFP could be obtained in the latter case. It was also shown that similar GFPs could be derived from sets of more broadly or more narrowly defined questionnaire scales, or from self- and others’ reports on a given inventory. Finally, it was shown that a GFP defined from eight personality inventories showed a modest degree of correlation with criterion variables such as ratings by others and act-frequency clusters.     

What does a general factor of personality look like in unshared environmental variance?

A general factor of personality (GFP) was obtained solely from unshared environment, by deriving it from the intercorrelations of monozygotic twin differences. This GFP was compared with a GFP derived from correlations reflecting all three components of variance—genes, shared environment, and unshared environment. In two large samples of adult Australian twins, for the items of two questionnaires, the two approaches gave virtually identical GFPs. However, in a sample of adolescent Australian twins, the two GFPs were correlated but distinct.     

In conversation with J. Philippe Rushton

The interview covers Rushton’s background in England, South Africa, and Canada, his education at the University of London (B.Sc., 1970; Ph.D., 1973), and his early research (1970–1980) on the social learning of generosity in 7- to 11-year olds. In his first book, Altruism, socialization, and society (1980), Rushton solved two “anomalies” for his social learning perspective—altruism in animals and traits in people—causing a “paradigm shift” for him toward sociobiology. He spent January to June 1981 at the University of California, Berkeley, to study the longitudinal stability of personality traits like altruism. There, he was influenced by Jensen’s work on g and race differences in rate of maturation and two-egg twinning. Subsequently, Rushton found that across 60 variables, Europeans fall between East Asians and Africans, closer to East Asians. He extrapolated Wilson’s (fast–slow) r-K life history theory to explain the pattern. Also covered is Rushton’s research on the heritability of altruism, and Genetic Similarity Theory explaining assortative mating and ethnic nepotism. Spouses and best friends are as similar as half-siblings and people randomly chosen from the same ethnic group are as related as first cousins. Altruism follows lines of similarity to replicate genes effectively. Rushton’s research on creativity is described.     

Rushton’s r–K life history theory of race differences in penis length and circumference examined in 113 populations

 and r–K life history theory that Mongoloids are the most K evolved, Caucasoids somewhat less K evolved, and Negroids the least K evolved is examined and extended in an analysis of data for erect penis length and circumference in two new data sets. These new data extend Rushton’s theory by presenting disaggregated data for penis size for European and North African/South Asian Caucasoids; for East Asian and Southeast Asian Mongoloids; for Inuit and Amerindians and Mestizos, and for thirteen mixed race samples. The results generally confirm and extend Rushton’s r–K life history theory.     

Criterion‐related validity of a Big Five general factor of personality from the TIPI to the IPIP

The criterion validity of a general factor of personality (GFP) extracted from personality scales of various lengths was explored in relation to organizational behavior and subjective well‐being with 288 employed students. Results indicated that GFPs extracted from as few as 10 items were significantly related to organizational outcomes. The relationship between GFP scores and outcomes generally increased with the length of the underlying scales, but these differences were reduced when correcting for reliability. Additionally, in over 60% of the analyses the GFPs exhibited higher correlations with specific outcomes compared to specific Big Five scores; this was true of 100% of the analyses using a broad, composite criterion. These results highlight the potential utility of the GFP as a screening tool when extracted from Big Five inventories from 10 to 100 items.     

Rushton’s contributions to the study of mental ability

This essay describes Rushton’s contribution to examining the nexus of intelligence, race, and genetics, specifically what I termed “Spearman’s hypothesis”. It states that Black–White differences are “most marked in just those [tests] which are known to be saturated with g”. I (Jensen) had confirmed this hypothesis using large data sets in the 1970s and 1980s and also found that Black–White differences were most marked on the more heritable rather than the more cultural subtests. Rushton confirmed and extended these findings in many highly innovative ways and demonstrated Spearman’s hypothesis applied among samples of Gypsy Roma in Serbia, and East Asian, European, South Asian, Colored and Black samples in South Africa. He has not only documented group differences in brain size, intelligence, life span, family structure, infant mortality, developmental precocity, personality, and temperament, and rates of two egg twinning, and crime among East Asians, Europeans, and Africans, but also provided a life history theory that explains them.     

The General Factor of Personality (GFP) Relates to Other Ratings of Character and Integrity: Two validity studies in personnel selection and training of the Dutch armed forces

In two studies, we tested whether scores on the general factor of personality (GFP) are associated with other ratings of character and integrity. In Study 1, a total of 3,670 applicants for a military job filled out personality surveys and went through a selection interview. GFPs extracted from two different personality surveys showed meaningful relationships with the job suitability judgments based on the interviews. In Study 2, supervisors rated the integrity of participants (N = 167) who followed a 4‐month military training at the Royal Dutch Military Police. GFPs extracted from three different surveys were correlated with integrity. The findings imply that the GFP is associated with behavioral outcomes, and that the GFP is potentially relevant for personnel selection and appraisal.     

The General Factor of Personality: The “Big One,” a self-evaluative trait,or a methodological gnat that won’t go away?

Though recent research indicates that the Big Five can be subsumed under a “General Factor of Personality” (GFP), considerable dissention remains about whether the GFP is a substantive trait (either a “mega”-trait or simply, positive self-evaluation), or a response artifact. To disentangle these potential explanations, we estimated GFP saturation based on scales within a single inventory (which may share response artifacts) versus between different inventories (wherein the GFP would be more substantive). Drawing on meta-analytic findings across 370 independent samples of 155,781 individuals, GFP saturation was reduced substantially when based on between inventory data (26%) compared to within inventory data (50%). These results indicate that the GFP functions as a response artifact that may be reduced by administering scales from different inventories. However, some GFP variance also appears to represent stable tendencies that span across inventories. Overall, the GFP appears to be partly a stable, self-evaluative trait and partly a set of response tendencies specific to a particular personality inventory. We discuss the implications of these results for academic and applied personality measurement.     

The general factor of personality and humor styles

The present study examined the phenotypic, genetic, and environmental correlations between a general factor of personality (GFP) and four humor styles: affiliative, self-enhancing, aggressive, and self-defeating. Participants were 571 same-sex adult twin pairs. Individuals completed the Humor Styles Questionnaire (HSQ) and a short form of the NEO personality scale (from which the GFP was extracted). The GFP was found to be heritable with an estimated value of .31. At the phenotypic level, the GFP was found to correlate significantly with the HSQ scales; positively with affiliative and self-enhancing, and negatively with aggressive and self-defeating. Three of the four phenotypic correlations were found to be attributable to correlated genetic factors, suggesting that these dimensions of humor styles and the GFP may have a common genetic factor.     

The General Factor of Personality: A reply to Muncer

In previous studies we have shown that a General Factor of Personality (GFP) occupies the apex of the hierarchy of personality as well as the apex of the personality disorders in the same way that g, the general factor of mental ability, occupies the apex in the organization of cognitive abilities (Rushton & Irwing, 2011). In a critique, Muncer (2011) re-analyzed one of our data sets and concluded there was no evidence for a GFP. He also argued against the evolutionary theory we had proposed for the origin of the GFP. In this rejoinder I rebut Muncer’s conclusion and describe how directional selection can explain the GFP.     

County-level IQ and fertility rates: A partial test of Differential-K theory

Human intelligence (IQ) correlates with a number of important life outcomes ranging from mortality and morbidity to social rank and status. Noticeably absent from the literature, however, has been a unifying framework from which to examine why IQ should correspond to so many seemingly disparate outcomes. Rushton’s Differential-K theory represents a theoretical perspective capable of accounting for the role of IQ in understanding human flourishing. We tested predictions suggested by Differential-K theory by examining the association between IQ at the aggregate level and two life-history variables: parental investment and fertility rates. Our results provide tentative support for some of the predictions of Differential-K theory.     

Developing a model for adult temperament

Hierarchical relations among theoretically generated lower order scales of adult temperament were explored in two studies. In Study One, 258 undergraduates completed the Adult Temperament Questionnaire (ATQ). A five-factor model emerged from exploratory factor analysis, with factors labeled Orienting Sensitivity, Effortful Control, Extraversion, Affiliativeness, and Negative Affect. This model showed considerable convergence with the Big Five. Study Two, with a community sample of 700 participants, yielded a six-factor model, distinguishing aggressive negative affect from non-aggressive negative affect. Relations of the six temperament factors to Cloninger’s TCI, the Five Factor Model, and the Multi-Language Seven were investigated, providing support for the discriminating power of the six-factor temperament model in understanding individual differences in adult temperament and personality.     

A General Factor of Personality in the Millon Clinical Multiaxial Inventory-III, the Dimensional Assessment of Personality Pathology, and the Personality Assessment Inventory

A General Factor of Personality (GFP) occupies the apex of the hierarchy in three prominent personality disorder inventories. On the Millon Clinical Multiaxial Inventory-III, a GFP accounted for 41% of the variance in two second-order factors, 31% of the variance in five first-order factors, and 26% of the variance in all 24 scales. On the Dimensional Assessment of Personality Pathology, a GFP accounted for 61% of the variance in six first-order factors and 36% of the variance in all 18 scales. In a cross-validation study of the Personality Assessment Inventory, a GFP accounted for 65% of the variance in two second-order factors, 47% of the variance in five first-order factors, and 27% of the variance in all 18 scales.     

Comparison of the construct validity of the Gray–Wilson Personality Questionnaire and the BIS/BAS scales

345 subjects completed a translated, shortened version of the Gray–Wilson Personality Questionnaire (GWPQ), along with Russian versions of Carver and White’s BIS/BAS scales, the Eysenck Personality Profiler, the Eysenck Personality Questionnaire, and Spielberger’s State-Trait Anxiety Inventory. Exploratory factor analysis of GWPQ items pointed to a three-factor solution and three new scales were created which demonstrated adequate psychometric characteristics. Confirmatory factor analysis of the BIS/BAS scales showed that a four-factor model best fitted the data but the three BAS subscales should be treated as sub-factors of a second-order factor. Structural equation modelling showed that GWPQ scales generally explained Eysenck’s dimensions better than BIS/BAS scales. The distinction between GWPQ and Carver and White’s scales mainly concerned BAS measures. GWPQ BAS captured more of Psychoticism, whereas Carver and White’s BAS captured more of Extraversion.     

The stability of the morning affect scale across age and gender

A limitation of the morningness–eveningness literature is the assumption that morningness is a ‘fixed’ construct. Morningness–eveningness scales are often developed on young adult samples, yet studies report that eveningness peaks in young adults with a shift to morningness from the age of 25 to 35 years of age. This age related change in morningness–eveningness may explain why these scales have limited success when applied in older samples. We tested this argument by developing a measurement model based on the Composite Scale of Morningness using a sample aged <30 years of age. Tucker’s congruence coefficient and confirmatory factor analysis indicated this solution was not a good fit in three older age groups. In contrast, we repeated this assessment using the ‘morning affect’ scale. This scale comprises items that measure morningness preference only. Model fit indicators suggested the ‘morning affect’ scale was a good fit across four age groups and gender.