Study: No Significant Difference in Male, Female Amygdala Size

According to a study published in the journal NeuroImage, there are no substantive amygdala size differences between men and women.

The amygdala is a brain region that aids in the processing of emotion, aggression, and fear responses. Previous research suggests many mental health conditions may originate in the amygdala.

A previous study led by Lise Eliot (an author of the latest study) also debunked the notion of sex-based brain differences. That study found no significant differences in hippocampal volume. The hippocampus plays a role in memory and connects emotions to the senses.

‘Male’ and ‘Female’ Amygdalae

The study analyzed 46 previous studies that looked at amygdala volume in 58 samples of men and women. This produced a total of 6,726 study participants matched for age.

Overall, men’s amygdalae were about 11-12% larger than women’s amygdalae. However, when researchers adjusted for overall size differences between men and women, this difference disappeared. The finding undermines previous research suggesting this emotion-processing brain region is proportionally larger in men.

Researchers sometimes refer to male and female amygdalae as sexually dimorphic, denoting a significant difference between the sexes. Analysts often use this difference to bolster claims about differences in behavior or emotions. Some say the difference in size helps scientists understand more about sex differences in certain mental health conditions, such as depression and anxiety. The new study presents evidence showing this claim is inaccurate; human amygdalae do not show sexual dimorphism.

Men and Women: More Similar Than Different

This finding adds to a wealth of gender research challenging the concept of binary male and female brains, and it may help experts to better understand mental health issues such as gender dysphoria.

Researchers are increasing studies in gender fluidity, particularly to understand transgender experiences. Some experts believe apparent psychological gender differences are inflated for political reasons. An interview with researcher Rosalind Barnett highlighted gender differences and stereotypes. In the interview, Barnett pointed to studies undermining purported gender stereotypes. One study showed mothers believed daughters would be more risk-averse than sons. Instead, boys were slightly more risk-averse than girls.

References:

1. Marwha, D., Halari, M., & Eliot, L. (2017). Meta-analysis reveals a lack of sexual dimorphism in human amygdala volume. NeuroImage, 147, 282-294. doi:10.1016/j.neuroimage.2016.12.021
2. Mounting challenge to brain sex differences. (2017, January 18). Retrieved from https://www.eurekalert.org/pub_releases/2017-01/rfuo-mct011717.php

The preceding article was solely written by the author named above. Any views and opinions expressed are not necessarily shared by GoodTherapy.org. Questions or concerns about the preceding article can be directed to the author or posted as a comment below.