Behavioural sex differences are to some extent related to sex differences in brain structure, but that this is mainly driven by differences in brain size, and causality should be interpreted cautiously

van Eijk, Liza, Dajiang Zhu, Baptiste Couvy-Duchesne, Lachlan T. Strike, Anthony J. Lee, Narelle K. Hansell, Paul Thompson, et al. 2021. “Are Sex Differences in Human Brain Structure Associated with Sex Differences in Behaviour?” PsyArXiv. April 28. doi:10.31234/osf.io/8fcve

Abstract: On average, men and women differ in brain structure and behaviour, raising the possibility of a link between sex differences in brain and behaviour. But women and men are also subject to different societal and cultural norms. We navigated this challenge by investigating variability of sex-differentiated brain structure within each sex. Using data from the Queensland Twin IMaging study (N=1,040) and Human Connectome Project (N=1,113), we obtained data-driven measures of individual differences along a male-female dimension for brain and behaviour based on average sex differences in brain structure and behaviour, respectively. We found a weak association between these brain and behavioural differences, driven by brain size. These brain and behavioural differences were moderately heritable. Our findings suggest that behavioural sex differences are to some extent related to sex differences in brain structure, but that this is mainly driven by differences in brain size, and causality should be interpreted cautiously.

Grumpy face during adult sleep: A clue to negative emotion during sleep?

Grumpy face during adult sleep: A clue to negative emotion during sleep? Jean‐Baptiste Maranci  Alexia Aussel  Marie Vidailhet  Isabelle Arnulf. Journal of Sleep Research, April 29 2021. https://doi.org/10.1111/jsr.13369

Summary: Negative facial expressions and frowns have been studied (albeit more rarely than smiles) in fetus’ and neonate’ sleep, but they have not been investigated during adult sleep. Video polysomnography (including corrugator muscle electromyography and face‐focussed video) was used to study negative facial expressions in sleeping adults, including healthy subjects and patients with/out parasomnia. Frowns were observed during sleep in 89/91 (97.8%) adults during normal (29 healthy subjects) and abnormal sleep (29 patients without parasomnia, 15 patients with disorders of arousal and 18 patients with rapid eye movement [REM] sleep behaviour disorder [RBD]). In healthy subjects, the following events occurred in decreasing frequency: isometric corrugator activations, brief frowns, and then prolonged frowns and raised eyebrows (both similarly rare). Frowns predominated in REM sleep, and had a lower frequency in non‐REM sleep. In healthy subjects, frowns were elementary and not associated with other face movements to the point of composing negative expressions. In contrast, frowns were occasionally associated with overt negative facial expressions in REM sleep in patients with RBD and a young patient with night terrors. They included mostly painful expressions and rarely sadness and anger in connection with apparently negative behaviours (shouts, painful moaning, and speeches). Frowns persist during normal sleep (mostly in REM sleep) in adults, but overt negative facial expressions are restricted to patients with parasomnia. Whether elementary frowns translate a negative dream emotion should be determined, but overt negative facial expressions during RBD could be used as a direct access to dream emotions.

Why surprisingly? "Surprisingly, sons—and not daughters—have a systematic negative effect on feminist self‐identification & support for electing more women, & a positive effect on support for traditional gender roles"

The Effect of Children's Gender on Parents’ Attitudes Toward Women. Nicole Y. Wesley  James C. Garand. Social Science Quarterly, April 26 2021. https://doi.org/10.1111/ssqu.12976

Abstract: Scholars have found that the gender of children—particularly, having daughters—has a discernible effect on parents’ attitudinal and behavioral support for the empowerment of women. In this article, we explore how the gender of children affects the gender attitudes of parents. Using data from the 2016 American National Election Study (ANES) survey, we estimate the effects of children's gender on parents’ feminist self‐identification, support for more women representatives, and attitudes toward traditional gender roles, both in general and separately for men and women. Surprisingly, we find that sons—and not daughters—have a systematic negative effect on feminist self‐identification and support for electing more women, as well as a positive effect on support for traditional gender roles. The effects of sons on feminist self‐identification and traditional gender roles are observed for both men and women, while the effects of sons on support for more women representatives are limited to women. It appears that having a son decreases support for feminist and egalitarian gender attitudes in both men and women to varying degrees across a variety of dimensions.