Earlier this year, researchers at Stanford University published the results of a study that explored sex differences in brain function. Using advanced deep learning techniques, they analyzed functional MRI (fMRI) datasets1 in order to identify and understand sex differences in the functional organization of the human brain and their relevance to behavior.
Analyzing multi-session fMRI images of 1,500 young adults aged 20 to 35, researchers found that “brain features associated with the default mode network, striatum, and limbic network consistently exhibited significant sex differences (effect sizes > 1.5) across sessions and independent cohorts.” ( Ryali et al, 2024) En Inglés: They identified distinct patterns of brain activity between males and females and sex differences in brain function linked to various behavioral traits.
The researchers and various commentators in the media explained that the implications of this research can provide insights into how these brain pattern differences might influence cognitive and emotional processes differently in males and females.2 According to the paper’s abstract:
Our results demonstrate that sex differences in functional brain dynamics are not only highly replicable and generalizable but also behaviorally relevant, challenging the notion of a continuum in male-female brain organization. Our findings underscore the crucial role of sex as a biological determinant in human brain organization, have significant implications for developing personalized sex-specific biomarkers in psychiatric and neurological disorders, and provide innovative AI-based computational tools for future research. Ryali et al, 2024
Gina Rippon, a British neurobiologist and author of The Gendered Brain: The new neuroscience that shatters the myth of the female brain, responded to the Stanford study. She acknowledged the study's findings but demurred from what she considered oversimplified interpretations thereof. She questioned whether the identified variations should be attributed solely to biological sex or if they also reflect gender-based experiences and societal influences.
Rippon suggested that the brain areas showing the most reliable distinctions between sexes in the Stanford study, the default mode network, are key parts of the
"social brain… which has evolved to be uniquely attuned to social interactions, and to pay attention to the outside world and to other people. [It] is the part of the brain in which we store key elements of social knowledge acquired by interaction, from the moment of birth (if not before) with the outside world – about yourself and about other people, about social rules and social norms, and even social stereotypes.” (Rippon, 2024).
This observation led her to propose that the differences observed in the study may be a product of both sex-specific, biological influences and of brain-changing gendered experiences. The complexity of factors influencing brain development and function must lead us to consider both biological and social factors in interpreting brain differences.
Perhaps Kathleen Stock can successfully squared the circle in this debate in her Substack, Unherd. While she is not a natural ally of Rippon in this context, she wrote:
“Given widespread acknowledgement of the importance of social environment for brain development, and also of the existence of neuroplasticity — including by all those who insist that underlying biological factors make a systematic difference to some of what human brains are, and what they can do — it is unclear which of Rippon’s opponents would disagree with her. As is often the case, what started life as two spicily hot contrasting takes have ended up occupying so much shared territory that it’s no longer clear what exactly is being argued about.” Stock, 2024
Data used in this study are available from the Human Connectome Project, the Nathan Kline Institute-Rockland Sample , and the MPI Leipzig Mind-Brain-Body dataset.
See e.g. Leonard Sax , Psychology Today ; Brooke Kato, The New York Post: Lindsay Kornick, Fox News.
References
Rippon, G. “Take it from a neuroscientist: searching for a ‘male’ and ‘female’ brain is a waste of time.” The Guardian, Feb 22, 2024.
Ryali S, Zhang Y, de Los Angeles C, Supekar K, Menon V. “Deep learning models reveal replicable, generalizable, and behaviorally relevant sex differences in human functional brain organization.” Proc Natl Acad Sci U S A. Feb 20, 2024. PMID: 38377194; PMCID: PMC10907309