Sex differences in personality scores on six scales: Many significant, but mostly small, differences

Sex differences in personality scores on six scales: Many significant, but mostly small, differences. Adrian Furnham & Luke Treglown. Current Psychology, Apr 10 2021. https://link.springer.com/article/10.1007/s12144-021-01675-x

Abstract: This study examined sex differences in domain and facet scores from six personality tests in various large adult samples. The aim was to document differences in large adult groups which might contribute new data to this highly contentious area. We reported on sex differences on the Myers-Briggs Type Indicator (MBTI); the Five Factor NEO-PI-R; the Hogan Personality Indicator (HPI); the Motives and Values Preferences Indicator (MVPI); the Hogan Development Survey (HDS) and the High Potential Trait Indicator (HPTI). Using multivariate ANOVAs we found that whilst there were many significant differences on these scores, which replicated other studies, the Cohen’s d statistic showed very few (3 out of 130) differences >.50. Results from each test were compared and contrasted, particularly where they are measuring the same trait construct. Implications and limitations for researchers interested in assessment and selection are discussed.

Discussion

The results of this study can be interpreted in various different ways. A sex-difference maximiser would note that a cursory glance at the six tables shows that the vast majority of ANOVAs (over 80%) shows significant sex differences, many at the p < .001 illustrating the fundamental point that there are many and important sex differences in personality, using a variety of measures and assessed at both the domain and facet level. On the other hand, the minimiser might take comfort in the effect size data (Cohen’s d) and note that there are very few large or even medium effect sizes, though this depends on how size is categorised.

Nearly all the hypotheses based on the previous literature were confirmed. Overall, the MBTI showed relatively small differences except in the Thinking-Feeling variable which has been the topic of much debate. It has been suggested (and refuted) that this factor is essentially measuring Neuroticism and hence the higher score for females which is consistent with the previous literature (Furnham, 2018),

The results from the NEO-PI-R confirmed some previous studies which showed males higher only on Conscientiousness but lower on Extraversion, Agreeableness, Openness and Neuroticism. The biggest domain differences were for three traits where females scored higher than males. The most unusual finding was the big difference on Openness (which was also shown in the HPTI trait of curiosity) where there is a limited literature and few speculations on sex differences. The smallest and fewest differences were on Consciousness and its facets. The facet analysis gave some indication of variability within domain but few where the differences went in the opposite direction. Two exceptions were the facets of assertiveness and excitement seeking in Extraversion where, as in many other studies males scored higher than females. Interestingly the highest d was for the Openness facet Feelings (d = .53) which reflects the finding in the MBTI. (Furnham, 1996).

The results of the HPI confirm previous studies with the biggest domain d’s being for Adjustment, Ambition and Curiosity with males scoring higher and Interpersonal Sensitivity with females scoring higher. Again, most of the facets scores went in the same direction though they did occasionally differ greatly in size: compare empathy and calmness in Adjustment.

The results of the replicated MVPI study showed two things: where there were significant differences the results went in the same direction, and that the biggest differences lay in male’s interest in power, business and science, values associated with entrepreneurship and work success (Furnham, 2018). Further, as in previous studies females scored higher in Altruism and Aesthetics.

The findings from the HDS show similar outcome in the two studies. When grouping the eleven traits into the recommended tri-partite system the results are clear: females tend to have scores on those traits moving away from (Cautious but not Reserved) and toward others (Dutiful not Diligent) while males score higher on traits in the moving against others category (especially Mischievous).

The final scale showed two of the six HPTI scales with relatively large differences: males score higher in Risk Approach and Ambiguity Acceptance which has been shown many times before. Although there was a sex difference on Competitiveness, the size of this was modest.

One interesting comparison could be between the scores of different tests which essentially (claimed to) measure the same construct. Thus, the sex difference d for Neuroticism in the NEO-PI-R was .35, Adjustment in the HPI was .30 and Adjustment in the HPTI was .14. Similarly, Conscientiousness in the NEO-PI-R was .12 and in the HPTI was .11, and Prudence .06. Equally the sex difference d in Agreeableness in the NEO-PI-R was .32 and Interpersonal Sensitivity in the HPI was .30. Therefore, the results seem to suggest similar sex differences on scales of different length and question measuring the same phenomenon. There were however exceptions: females were more Extraverted and Open on the NEO=PI-R, but less Sociable and Curious on the HPI.

One interesting issue concerns revisiting each question and facet to determine whether there was any inherent sex bias in the question wording and whether if these were removed the overall d would decline. This is not an issue of attempted to deny or reduce differences that exist but rather trying to reduce artefacts arising from question selection. Certainly, with changes in society, particularly with reference to sex and gender differences, questionnaire wording could cause both offense and differences in interpretation unless they are constantly updated.

Another issue to arise from this study is the great variability in the facet score items and labels that are essentially measuring the same dimension. Compare for instance the six Openness facets of the NEO-PI-R with six facets of the HPI. Given these labels it is expected that these two measures are relatively weakly correlated and measuring rather different factors.

Finally accepting that there are some real, biologically based, stable sex differences, as opposed to socialised gender differences, in personality traits the question arises as to why they occur. Results such as these cannot inform the nature-nurture debate, with (most) evolutionary psychologists offering a cohesive (and for some convincing) argument as to why there are replicable, consistent and cross-cultural findings. Minimizers who reject the “biology as destiny” approach attempt to explain all these differences in terms of primary and secondary socialisation (Buss, 1995). However, in a big review study Schmitt et al. (2017) concluded: “Social role theory appears inadequate for explaining some of the observed cultural variations in men’s and women’s personalities. Evolutionary theories regarding ecologically-evoked gender differences are described that may prove more useful in explaining global variation in human personality” (p45).

This study, like all, others has limitations. All participants were British adults taking part in a compulsory assessment centre. Though they might have been tempted by impression management there is no reason to suspect that there were sex differences in this behaviour. The reason why males outnumber females tended to reflect the profile of middle managers in those organisations which reflected all sectors, public and private. The sample was thus biased in terms of age, education and class and the question remains whether a more representative sample of people from a wider age range and social class background would have shown more or fewer sex differences. Furthermore, nearly all participants were from Europe and the effects of culture were thus not explored. It could be that sex differences are smaller in more Western, individualistic, democratic, egalitarian, and higher gender-parity cultural contexts than those from more traditional, developing countries.

It has been argued that personality changes over time and it may be that sex differences and similarities in personality are different for young, middle-aged and older participants (Roberts et al., 2001). Finally there is always the possibility that there are sex differences is self-report behaviours and biases, such that females exhibit more humility and males more hubris and that therefore some observed differences are more due to other factors and artefacts than actual personality differences.