The gender imbalance in STEM subjects dominates current debates about women's underrepresentation in academia. However, women are well represented at the Ph.D. level in some sciences and poorly represented in some humanities (e.g., in 2011, 54% of U.S. Ph.D.'s in molecular biology were women versus only 31% in philosophy). We hypothesize that, across the academic spectrum, women are underrepresented in fields whose practitioners believe that raw, innate talent is the main requirement for success, because women are stereotyped as not possessing such talent. This hypothesis extends to African Americans' underrepresentation as well, as this group is subject to similar stereotypes. Results from a nationwide survey of academics support our hypothesis (termed the field-specific ability beliefs hypothesis) over three competing hypotheses. L aboratory, observational, and historical evidence reveals pervasive cultural associations linking men but not women with raw intellectual talent (1-4). Given these ambient stereotypes, women may be underrepresented in academic disciplines that are thought to require such inherent aptitude. We term this the field-specific ability beliefs hypothesis ( fig. S1 ). Current discourse about women in academia focuses mainly on women's underrepresentation in (natural) science, technology, engineering, and mathematics (STEM) (5). However, STEM disciplines vary in their female representation ( fig. S2 ) (5, 6). Recently, women have earned approximately half of all Ph.D.'s in molecular biology and neuroscience in the United States, but fewer than 20% of all Ph.D.'s in physics and computer science (7). The social sciences and humanities (SocSci/Hum) exhibit similar variability. Women are currently earning more than 70% of all Ph.D.'s in art history and psychology, but fewer than 35% of all Ph.D.'s in economics and philosophy (7). Thus, broadening the scope of inquiry beyond STEM fields might reveal new explanations and solutions for gender gaps (8). We offer evidence that the field-specific ability beliefs hypothesis can account for the distribution of gender gaps across the entire academic spectrum. Individuals' beliefs about what is required for success in an activity vary in their emphasis on fixed, innate talent (9). Similarly, practitioners of different disciplines may vary in the extent to which they believe that success in their discipline requires such talent. Because women are often negatively stereotyped on this dimension (1-4), they may find the academic fields that emphasize such talent to be inhospitable. There are several mechanisms by which these field-specific ability beliefs might influence women's participation. The practitioners of disciplines that emphasize raw aptitude may doubt that women possess this sort of aptitude and may therefore exhibit biases against them (10). The emphasis on raw aptitude may activate the negative stereotypes in women's own minds, making them vulnerable to stereotype threat (11). If women internalize the stereotypes, they may also decide that these fields are not for them (12). As a result of these processes, women may be less represented in "brilliance-required" fields. We used a large-scale, nationwide study of academics from 30 disciplines to evaluate the field-specific ability beliefs hypothesis, along with three competing hypotheses. The first competitor concerns possible gender differences in willingness or ability to work long hours (13): The more demanding a discipline in terms of work hours, the fewer the women. The second competing hypothesis concerns possible gender differences at the high end of the aptitude distribution [(14, 15); but see (16, 17) for criticism]. Such differences might cause greater gender gaps in fields that, by virtue of their selectivity, sample from the extreme right of the aptitude distribution: The more selective a discipline, the fewer the women. The third competing hypothesis concerns possible differences among fields in the extent to which they require systemizing (the ability to think systematically and abstractly) or empathizing (the ability to understand thoughts and emotions in an insightful way): The more a discipline prioritizes systemizing over empathizing, the fewer the women (14, 18, 19) . Our findings suggest that the field-specific ability beliefs hypothesis, unlike these three competitors, is able to predict women's representation across all of academia, as well as the representation of other similarly stigmatized groups (e.g., African Americans). We surveyed faculty, postdoctoral fellows, and graduate students (N = 1820) from 30 disciplines (12 STEM, 18 SocSci/Hum) (table S1) at geographically diverse high-profile public and private research universities across the United States. Participants were asked questions concerning their own discipline (table S2) ; responses in each discipline were averaged (tables S3 and S4), and analyses were conducted over disciplines (not individuals). As our dependent measure, we used the percentage of female Ph.D. recipients in each discipline (7). To assess field-specific ability beliefs, we asked participants to rate their agreement with four statements concerning what is required for success in their field (e.g., "Being a top scholar of [discipline] requires a special aptitude that just can't be taught") (table S2). Respondents rated both the extent to which they personally agreed with these statements, and the extent to which they believed other people in their field would agree with the statements. Because answers to these eight questions displayed very similar patterns (a = 0.90), they were averaged to produce a field-specific ability belief score for each discipline (with higher scores indicating more emphasis on raw ability). As predicted, the more a field valued giftedness, the fewer the female Ph.D.'s. Field-specific ability belief scores were significantly correlated with female representation across all 30 fields [correlation coefficient r(28) = −0.60, P < 0.001], in STEM alone [r(10) = −0.64, P = 0.025], and in SocSci/Hum alone [r(16) = −0.62, P = 0.006] (Fig. 1) . In a hierarchical regression with a STEM indicator variable entered in the first step and field-specific ability belief scores entered in the second (Table 1 , models 1 and 2), adding the ability belief variable significantly increased the variance accounted for, DR 2 = 0.29, P < 0.001. To assess work demands, we asked participants to report the number of hours they worked per week, on-campus and off-campus (table S2) . There was no correlation between the total number of hours worked (on-plus off-campus) and female representation, r(28) = −0.03, P = 0.895. Women tended to be underrepresented in fields whose practitioners worked more on-campus hours, but this correlation was not significant either, r(28) = −0.32, P = 0.088. No significant correlations with on-campus hours were found either within STEM, r(10) = 0.46, P = 0.131 (note the positive coefficient here), or within SocSci/ Hum, r(16) = −0.07, P = 0.772. Adding on-campus hours to the hierarchical regression predicting
Research shows that women are significantly underrepresented in academic fields "believed to require attributes such as brilliance and genius" REF including computer science.
Expectations of brilliance underlie gender distributions across academic disciplines
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