Cambridge study reveals sex-based attention differences appear within hours of birth

Research at Cambridge University indicates that gender-specific attention patterns are observable in infants just hours after birth, suggesting prenatal influences shape early behaviour before social interaction begins.

A University of Cambridge study suggests that sex-based differences in attention may be visible within hours of birth, before babies have had any meaningful exposure to toys, language or other social cues. Researchers working with 130 newborns found that girls, on average, spent longer looking at human faces, while boys were more likely to fix on a moving mechanical object.

The experiment, carried out soon after delivery, placed two short videos side by side for each infant: one showing a human face and the other showing a Newton’s cradle, the desk toy with metal spheres that swing and strike one another. Both boys and girls generally showed a preference for faces, but the girls tended to sustain that gaze for longer, whereas the boys directed relatively more attention towards the object.

According to the Cambridge team, the findings add to evidence that some average differences between males and females may begin before birth rather than being shaped only by upbringing. The researchers said prenatal influences such as sex hormones and genetics could play a role, although they stressed that development is always a mix of biology and environment rather than a simple either-or explanation.

The study was led by Yumna Khan at Cambridge’s Autism Research Centre, and supervised by Simon Baron-Cohen. Khan said the results suggest that average sex differences can already be seen at birth not only in brain structure but also in attention and behaviour. Baron-Cohen said the early contrast points to prenatal factors, while the researchers also cautioned that the findings describe group averages, not rules that apply to every child.

That distinction matters. Carrie Allison, deputy director of the centre, said the differences were not true of all boys or all girls and that there is substantial overlap between the two groups. The researchers also suggested the work may help explain why girls often appear to develop some language and social skills earlier than boys, though they emphasised that individual children develop at different rates and are not determined by sex alone.