Sexing the Autistic Brain: Extreme Male?

This post was co-authored by Barbara D’Entremont, Department of Psychology, University of New Brunswick, Fredericton, Canada.

Autism Spectrum Disorder (ASD) is characterized by deficits in social-communication, alongside patterns of restricted and repetitive behaviors (American Psychiatric Association, 2013). In looking for a potential explanation of this disorder, Simon Baron-Cohen noticed the higher prevalence of ASD in males than in females as well as a parallel between domains where cognitive gender differences have been reported and areas of high and low abilities in ASD.

This led him to formulate the extreme male brain theory of autism (Baron-Cohen, 2002). As a starting point to this theory, Baron-Cohen argued that sex differences can be classified as falling into two domains of human thought: empathizing and systemizing. Empathizing refers to the tendency to attribute mental states to others or to have empathy or sympathy. It has also been equated with “theory of mind” or the ability to understand that others have thoughts, emotions, and desires. Systemizing is the tendency to organize things into systems or to develop rules or principles to understand complex systems.

Baron-Cohen further argued that, within the general population, males have a propensity towards systemizing whereas females have a propensity towards empathizing. Following up on these ideas, Baron-Cohen (2002) suggested that individuals with ASD show an extreme pattern of hyper systemizing and hypo empathizing and labeled them as having an extreme male brain.

Baron-Cohen presented evidence supporting a female advantage in social tasks (e.g., turn-taking, responding to the distress of others, theory of mind, decoding facial expressions) and a male advantage in activities that can be characterized as involving input-operation-output (e.g., math, physics, engineering, construction tasks, spatial abilities such as mental rotation) to support his view.

Baron-Cohen and his colleagues have also developed a number of tests to capture differences in these domains with males and females showing differences in the expected direction and results with individuals with ASD showing an extreme male pattern (e.g., Baron-Cohen, Wheelwright, Hill, Raste, & Plumb, 2001; Goldenfeld, Baron-Cohen & Wheelwright, 2005). Thus, because individuals with ASD score lower than typical boys on empathizing and higher than typical boys on systemizing, Baron-Cohen (2002) suggested that they have an “extreme male brain.” Baron-Cohen has also offered evidence of biological markers to support his theory, based mostly on the claim that fetal testosterone level is positively related with higher levels of ASD symptomatology in children 6 to 10 years of age (Auyeung, Baron-Cohen, Ashwin, Knickmeyer, Taylor, & Hackett, 2009; see also Manning, Baron-Cohen, Wheelwright, & Fink, 2010).

Not surprisingly, the extreme male brain theory of autism has been criticized on many fronts. Interested readers might want to consult the excellent critique published by Krahn and Fenton (2012). The fetal testosterone link is criticized in Grossi and Fine (2012), among others.

In the context of this post, however, the question that begs asking is: How can we be discussing an extreme “male brain” when the literature clearly suggests that there is no such thing as a male brain? Indeed, my series of posts on this blog, “Sexing the Brain,” concluded that sex differences in the brain are minimal. In reality, much of the extreme male brain theory seems to be based on areas where small and variable effect sizes are found (e.g., verbal abilities) and on stereotypical expectations (e.g., for math and science) and it requires revisions based on recent data.

For example, recent meta-analyses suggest a trivial sex difference in math (Lindberg, Hyde, Petersen, & Linn, 2011) and even a generalized female advantage in school grades, regardless of course content (Voyer & Voyer, 2014). Therefore, the possibility that there would only be two types of brains (male or female pattern, essentially) greatly simplifies the functioning of that highly complex organ and applies a gendered theorization when it is not warranted.

By jumping so quickly to biological explanations of these (questionable) sex differences, proponents of the extreme male brain theory of autism also seem to disregard the possibility that, for much of the literature they cite to support their view, it is not possible to rule out social learning. For example, spatial abilities can be improved through training (Uttal, Meadow, Tipton, Hand, Alden, Warren, & Newcombe, 2013). Considering that the extreme male brain theory is actually a misnomer, it might be better labeled extreme systemizing. However, even then, some would argue that the advantage of individuals with ASD in systemizing is greatly exaggerated (Jack, 2011).

In fact, a quote from the abstract of Jack’s (2011) paper provides an important warning on the problems associated with accounts of autism such as the extreme male brain theory. Specifically, such theories “overlook other important aspects of ASD, including alternative theories, the presence of autistic women and girls, and the needs and interests of autistic people themselves” (from the abstract of Jack, 2011). This suggests that it is time to move on and consider more generalizable avenues to account for autism and improve the quality of life for those affected by it rather than treating popularized gender differences as if they were a concrete fact.