Sex and gender correlates of sexually polymorphic cognition

Abstract

Background

Sexually polymorphic cognition (SPC) results from the interaction between biological (birth-assigned sex (BAS), sex hormones) and socio-cultural (gender identity, gender roles, sexual orientation) factors. The literature remains quite mixed regarding the magnitude of the effects of these variables. This project used a battery of classic cognitive tests designed to assess the influence of sex hormones on cognitive performance. At the same time, we aimed to assess the inter-related and respective effects that BAS, sex hormones, and gender-related factors have on SPC.

Methods

We recruited 222 adults who completed eight cognitive tasks that assessed a variety of cognitive domains during a 150-min session. Subgroups were separated based on gender identity and sexual orientation and recruited as follows: cisgender heterosexual men ( n = 46), cisgender non-heterosexual men ( n = 36), cisgender heterosexual women ( n = 36), cisgender non-heterosexual women ( n = 38), gender diverse ( n = 66). Saliva samples were collected before, during, and after the test to assess testosterone, estradiol, progesterone, cortisol, and dehydroepiandrosterone. Psychosocial variables were derived from self-report questionnaires.

Results

Cognitive performance reflects sex and gender differences that are partially consistent with the literature. Interestingly, biological factors seem to better explain differences in male-typed cognitive tasks (i.e., spatial), while psychosocial factors seem to better explain differences in female-typed cognitive tasks (i.e., verbal).

Conclusion

Our results establish a better comprehension of SPC over and above the effects of BAS as a binary variable. We highlight the importance of treating sex as a biological factor and gender as a socio-cultural factor together since they collectively influence SPC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-023-00579-8.

Plain Language Summary

Many studies show sex differences in cognitive abilities. In general, women outperform men in verbal tasks and fine motor skills, while men outperform women in spatial orientation and mental rotation tasks. These differences underlie research on sexually polymorphic cognition, a concept influenced by sex hormones (estradiol, progesterone, and testosterone) as well as birth-assigned sex. In addition to these biological factors, socio-cultural gender factors such as gender identity (the gender we feel and embody), gender roles (masculine and feminine expressions based on stereotypes), as well as sexual orientation are all known to influence cognition as well. We provide a broader understanding by accounting for both sex and gender factors. Our team recruited 222 adults separated into 5 sub-groups based on birth-assigned sex, gender identity, and sexual orientation. Each participant completed eight sexually polymorphic cognitive tasks. In this 150-min experimental protocol, saliva samples were collected before, during, and after the test to assess testosterone, estradiol, progesterone, cortisol, and dehydroepiandrosterone. Psychosocial variables were derived from self-report questionnaires. Results showed that spatial cognition was better explained by biological sex factors, while verbal cognition was better explained by socio-cultural gender factors. Taken together, our findings demonstrate the importance of considering sex-based and gender-based factors collectively and, respectively, when studying sex differences in cognition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-023-00579-8.

Highlights

• Sex differences in cognition have been extensively studied but remain unclear

• Incorporating sex and gender factors in cognitive studies is essential

• Inclusion of sexual and gender diversity further explain cognitive sex differences

• Contribution of each sex and gender factor depend on the cognitive function observed

• Spatial cognition appears more sexed, while verbal cognition appears more gendered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-023-00579-8.