# Gender differences in IQ among undergraduate psychology students

While marking undergraduate coursework relating to gender differences, it occurred to me that there could well be systematic effects of gender on IQ among the undergraduate populations relied on for so much of psychological research.

My impression is that male psychology students, who are in the minority, are likely to be on average more intelligent than female ones, because (warning, anecdotal evidence, and broad sweeping statements, ahead):

• Women tend to study psychology at undergraduate level in the belief that it will involve understanding or helping people, while men tend to be more interested in psychology as a science. Although women's motivation is probably the more admirable one, men's seems likely to indicate higher general intelligence.
• Despite making up a small minority of undergraduate students, men make up about 50% of psychologists at later stages (PhD onwards), with the possible exception of clinical/educational psychologists.
• Men's IQ's are more variable - there are more male geniuses, but also more men with extremely low IQ's. Since university students will have above average IQs in general, we would expect more men to have extremely high IQs in this sample (for the same reason as we would expect men who don't finish second-level education to have lower IQs on average than women who don't).

However, all this speculation aside, I haven't been able to find any research putting this apparently simple, and possibly very important, for the interpretation of a lot of research, idea to the test.

Are there any?

• This is only anecdotal, so only a comment. (a) Most males studying psychology at my university want to become therapists and study psychology because they want to understand and help people. The first step would be to verify the motivation of female and male students, because your impression might be wrong or not general. (b) 50 yrs ago psycholy students were mostly male. That is one reason why most working psychologists are or have been male. Some would also argue that there is gender discrimination at work. Both would need to be checked. – user3116 Jun 4 '15 at 5:58
• (c) Testing the audience of one lecture (on psychology of personality) our professor then presented the results which showed that among us psychology students the males had a higher intelligence on average than the females. I don't remember the test we took and the exact numbers, but the difference was massive (about 5 to 10 points, if I'm not mistaken). The most intelligent individuals were in fact male. (d) Why don't you simply test a sample from your pool? – user3116 Jun 4 '15 at 6:03

I think what happens is that researchers often don't report on - or at least don't highlight - uninteresting results, partly because of the difficulty getting uninteresting results published. So given that gender differences in IQ in general are eliminated for validity, a lack of gender differences in IQ amongst a seemingly arbitrary sub-population such as undergraduate psychology students doesn't seem to merit attention. I similarly wouldn't expect to find a study published about the lack of gender differences in IQ amongst say, red-haired truck drivers with carpal tunnel syndrome. In fact, researchers often highlight the usefulness of psychology students as research subjects for being representative of the general population in many respects, in addition to being convenient to recruit.

On the other hand, as undergraduate psychology students are so often used as subjects in many areas of research, it shouldn't be too difficult to find data that records both IQ and gender, and confirm that it is indeed uninteresting.

Starting in the 1990's, there was a flurry of research based on some interesting results - that there are gender differences in estimates of IQ (presumably due to some stereotypes). Although these studies don't specifically focus on gender differences in IQ amongst undergraduate psychology students, some of them do measure and report gender and IQ, and in some cases, the subjects are in fact undergraduate psychology students. Here are some examples:

... despite the fact that psychology attaches no significant gender differences to general intelligence, psychology students appeared to believe in the superiority of males.

Two hundred and forty-five undergraduate psychology students (65% female) participated in the present study for extra course credit. ... The only association with cognitive ability was the small positive correlation between IQ and narcissism.

A total of 182 undergraduate students from British and American universities participated in this study. ... 49 males and 132 females were included in the statistical analysis ... Students participated in this study as part of two lectures on personality and intelligence assessment ... Correlations between Raven's test scores (Gf), SAI, ... gender and age are presented in Table 1.

(Sex is listed in Table 1 as having a correlation with Gf of -.00.) There are many other similar examples from all over the world.

In some ways, the premise of the question seems odd: In as much as IQ is correlated with academic achievement (and it is, again for validity), it should correlate as much with acceptance to the program as it does with graduation results. Thus, other reasons, such as discrimination or life choices might seem like better explanations. Another possibility to consider is that psychology students are not always enrolled in the psychology program, and might include a disproportionate number of female students early on, who are actually from other programs that list psychology as a requirement, and have a female dominated enrolment throughout (eg, nursing).

However, the question is not entirely baseless. More recent research has started to use alternative measures of intelligence that are not gender-corrected as standard IQ tests are. This research does show gender bias in different sub-types of intelligence, and to some degree, overall intelligence. From a 2011 thesis:

No uniform agreement exists about male advantage in general intelligence (‘g’) (e.g. Colom & Garcia-Lopez, 2002; Deary et al., 2003; Halpern et al., 2007; Jackson & Rushton, 2006; Lynn, 1999; Spelke, 2005), with historically no sex differences presumed, as evidenced by the development of standardised intelligence tests (e.g. Ackerman, 2006; Wechsler, 1944). Recent investigations have supplied contradicting data, with male advantage reported on various measures of Gf and Gc, such as General Knowledge Test (GKT), Raven’s Standard and Progressive Matrices (SPM) and Wechsler Adult Intelligence Scale (WAIS) (cf. Lynn, Allik, & Irwing, 2004; Lynn, Irwing, & Cammock, 2001; Lynn, Wilberg, & Margraf-Stiksrud, 2004).

The paper goes on to describe such a study, conducted on 85 undergraduate psychology students, that confirms the gender bias in "g" in that population as well.

• My question wasn't about gender differences in $g$ in the population - I've a little bit of familiarity with that literature, enough to know that I don't want to know any more about it - but about possible selection biases which lead to gender differences within this extremely well studied population. The thesis you refer to at the end touches on the topic, but I haven't seen anyone run the analysis that would explicitly answer my question: collate IQ measures from thousands of undergraduates, and compare any gender effects there to any found in the population norming sample for those tests. – Eoin May 20 '15 at 9:51
• Just to reiterate, my interest in this isn't from a psychometric perspective - I really don't care if there does turn out to be some tiny gender difference in average IQ - but from an experimentalist perspective: I want to know if there are systematic variations in cognitive ability (and therefore reasoning ability) in the population on which I run all of my experiments. – Eoin May 20 '15 at 9:53
• I thought the original question was quite clear, but now I'm confused. The study you are looking for - that collects IQ scores from thousands of students - what would that add that isn't already covered? If such a study were to reveal gender differences in IQ, then shouldn't we also see them in all studies that include gender and IQ measures? – Arnon Weinberg May 20 '15 at 18:16

One meta-analysis of gender differences in cognitive abilities (verbal ability, quantitative ability, and visual–spatial ability):

Results indicate that gender differences in all of these abilities were small: For verbal ability, the median ω–2 was .01 and the median d was .24; for quantitative ability, the median values of ω–2 and d were .01 and .43; for visual–spatial ability, they were .043 and .45; and for field articulation, ω–2 was .025 and d was .51

• Hyde, J. S. (1981). How large are cognitive gender differences? A meta-analysis using! w² and d.. American Psychologist, 36(8), 892.

One study completed using Israeli military IQ tests over 8 years found no gender differences in IQ.

The 1976 to 1984 data allow a comparison of male gains with female gains on both tests of IQ. They are virtually identical.

• Flynn, J. R. (1998). Israeli military IQ tests: Gender differences small; IQ gains large. Journal of Biosocial Science, 30(04), 541-553.

I can find no evidence to suggest that men have a higher IQ and that is why they pursue psychology to a higher level. I can't seem to find any research specifically on male IQ in a female-dominated undergraduate subject such as psychology.

However, In regards to men making up more phd students:

This study is about studying a male-dominated subject at undergraduate level, however could be applied to furthering study from a female dominated (undergrad psychology) into a male dominated (phd psychology) subject:

First-year and final year female undergraduates in a male-dominated academic area (ie, math, science, or engineering) reported higher levels of discrimination and stereotype threat than those in a female-dominated academic area.

• Steele, J., James, J. B., & Barnett, R. C. (2002). Learning in a Man’S World: Examining the Perceptions of Undergraduate Women in Male‐Dominated Academic Areas. Psychology of Women Quarterly, 26(1), 46-50.

Another study found that women don't choose not to pursue a PhD because their IQ isn't high enough, but rather they may have concerns about flexibility:

Findings suggest that desire for a flexible job, high time demands of an occupation, and low intrinsic value of physical science were the best predictors of women changing their occupational aspirations out of male dominated fields. These results suggest that despite the women’s movement and more efforts in society to open occupational doors to traditional male-jobs for women, concerns about balancing career and family, together with lower value for science-related domains, continue to steer young women away from occupations in traditionally male-dominated fields, where their abilities and ambitions may lie.

• Frome, P. M., Alfeld, C. J., Eccles, J. S., & Barber, B. L. (2006). Why don't they want a male-dominated job? An investigation of young women who changed their occupational aspirations. Educational Research and Evaluation, 12(4), 359-372.