Sex/Gender Differences: the Biopsychosocial Approach

Cognitive & Biological Psychology

Belfi et al, 2014

used MRI to investigate relationship between gender roles and brain structure in children

Children’s Sex Role Inventory (Boldizar, 1991)

masc-fem continuum score with higher being more masc and lower being more fem

• male sex associated with higher continuum score, but not strong enough to say sex/gender are the same

• masculinity positively correlated with white matter volumes in frontal lobe

• femininity positively correlated with grey matter volumes in the temporal lobe

• effects remained after biological sex was controlled for

direction of causality in relationship unclear, but effect may represent sex/gender related environmental influence on sex/gender differences in the brain beyond biological sex

Wraga et al, 2006

showed that mental rotation performance could be affected by exposure to gender stereotypes

biopsychosocial approach suggests socio-cultural factors can influence biological factors (stress effects, changes to neural activity, impact on hormones)

Wraga et al, 2007

used fMRI to investigate effects of gender stereotyping on neural underpinnings of visuospatial performance in women

• significantly poorer performance in negative stereotype groups (increased error rates)

• improved performance on in positive stereotype group

• the poorer performance correlated with greater activation in brain regions associated with emotional processing (orbital and medial frontal gyri, anterior cingulate cortex)

suggests negative stereotypes —> increased emotional load —> poorer performance

unconscious level of stereotype effect: women reported being unaffected

• positive performance correlated with increased activation of secondary visual processing areas, superior occipital gyrus, and anterior prefrontal gyrus, regions typically associated with good mental-rotation performance and higher-order cognitive functions

• no activation of areas associated with emotional processing/emotional load

Hausmann et al, 2009

investigated stereotype threat effects using cognitive testing and endocrinological measures

assessed testosterone because high testosterone in women = more threat effects

• men’s mental rotation performance positively related to testosterone

• gender stereotype score was negatively related to mental rotation performance in women

Pletzer et al, 2019

similar results to Hausmann et al, 2009 concerning relationship between sex hormones, mental rotation and self-identified masculinity/femininity

• interactive relationship exists between sex/gender relevant biological, psychological, and social factors

• this relationship is capable of influencing sex/gender differences in cognition

Karkazis, 2019

neither biological sex nor gender can be accurately conceptualized as binary

Rauch & Eliot, 2022

research to date has been limited by a lack of universal agreement on the definitions of sex and gender — majority of studies interested in sex/gender differences separate into dichotomous male/female groups

Zhang et al, 2021

combined connectivity data from four international databases to create a brain-gender continuum of resting state networks

brain-gender continuum was mapped onto measure internalising and externalising — these differ according to masculinity/femininity

resulted in an association curve where “androgynous” middle continuum brains were associated with the lowest levels of internalisation

Dotson and Duarte, 2019

the importance of diversity in cognitive neuroscience

focuses on racial diversity, but arguments are applicable to sex/gender diversity

• only 8% of studies in this review considered the effect of sex/gender, even fewer reported the sex/gender distribution

• major implications for reproducibility, generalisability, and development of treatments

• biological differences between cis and trans people unaccounted for

Harrison et al, 2020

interview 8 trans people for an in-depth understanding of the lived experience of gender dysphoria

three themes emerged:

• accessing healthcare services

• searching for acceptance

• impact of gender dysphoria on psychological wellbeing

Moolchaem et al, 2015

synthesis of qualitative studies that explore the lived experiences of trans people

• sense of being born in wrong body > transition of physical appearance > transgression of male-female dichotomous norm

• life beyond boundaries of traditional social norms > social exclusion

Kurth et al, 2022

one of very few studies conducting neuroimaging on transgender participants

do brains of transgender people resemble their birth sex or their gender identity?

• transgender women’s brains fit in between two cisgender groups — suggests socio-psychological determinants in brain structure before hormone therapy

• this suggests gender identity shapes brain structure much more than biological sex

Mueller et al, 2021

compared structural MRI data between cis and trans groups across a range of measures

• both transgender groups differed from cisgender groups with respect to subcortical brain volumes and surface area

• structural patterns differed between all 4 groups — specific pattern depended on brain region examined and direction of gender identiity

suggests that transgender participants have a unique brain phenotype rather than a shift along male/female spectrum

Giannantonio et al, 2024

aimed to investigate experiences and milestones of non-binary identification, and identify challenges of living in a binary world as a non-binary person

four domains:

1. growing up in a binary world

2. gender dysphoria

3. nonbinary awareness

4. looking forward

Harrison et al, 2020

qualitative study investigating impact of gender-affirming therapy on quality of life in transgender people

Tordoff et al, 2022

quantitative study on quality of life in transgender people receiving gender-affirming therapy

Aghi et al, 2022

comprehensive review of current translational research that could be applied to the study and practice of gender affirming therapy

• argue that current research fails to address the needs of GAHT users, and further translational research is needed

• conclude that if necessary and important steps are taken to address these issues, translational research on GAHTs will greatly benefit the health care outcomes of trans and gender non-conforming people

Sahin and Yalcinkaya, 2020

investigated the impact of engaging with scientific research into sex and gender on underlying beliefs regarding gender essentialism, sexism, and gender inequality

• two studies exposed participants to neuroscience research findings concerning sex/gender differences and similarities in the brain, and measured participants gender essentialist beliefs

• across both studies, participants who were exposed to scientific evidence on brain similarities between men and women reported lower gender essentialism than those in the control and brain difference conditions

suggests that exposure to information on brain similarities between men and women can challenge essentialist views on gender and importantly, indirectly relate to sexism and justification of gender inequality

also has implications for improving gender equality in cultures where this remains an issue.