The Brain, Its Size, Evolution, Gender, and Sociocultural Impact

Preliminary research suggests that biological sex (sex) and sociocultural, psychological, and psychological gender (gender) are represented differently in the brain. The study analysed functional magnetic resonance imaging (fMRI) data from 4,757 children aged nine or ten. Specific brain networks related to biological sex, such as the visual and motor networks, displayed more defined roles. Conversely, the networks associated with sociocultural gender differences were more widely distributed throughout the brain. These findings emphasise the importance of considering the social influence of gender in neurological research and avoiding confusion with physiological sex.

Contrary to long-held assumptions, the largest animals do not have proportionally larger brains. This is not the case in humans, as larger brains, relative to body size, are associated with intelligence, social bonding, and behavioural complexity. Homo sapiens evolved more than 20 times faster than all other mammalian species, leading to the significant brain size characteristic of humanity today. Across mammalian groups, there have been rapid changes towards both smaller and larger brain sizes. Primates, rodents, and carnivores experienced the most pronounced and fastest changes in brain size among the animal groups.