Trends in Cognitive Sciences
OpinionThe extreme male brain theory of autism
Section snippets
The main brain types
I will be arguing that systemising and empathising are two key dimensions in defining the male and female brain. We all have both systemising and empathising skills. One can immediately envisage five broad brain types (see also Fig. 1):
- 1.
Individuals in whom empathising is more developed than systemising. For shorthand, E > S (or Type E). This is what we will call the ‘female brain’.
- 2.
Individuals in whom systemising is more developed than empathising. For shorthand, S > E (or Type S). This is what
The female brain: empathising
What is the evidence for female superiority in empathising? In the studies summarised here, sex differences of a small but statistically significant magnitude have been found.
The male brain: systemising
The relevant domains in which to look for evidence include any that are in principle rule-governed. Thus, chess and football are good examples of systems; faces and conversations are not. Systemising involves monitoring three things in order: input–operation–output. The operation is what you did to the input, or what happened to the input, to produce the output.
Autism: an extreme form of the male brain
Autism is diagnosed when a person shows abnormalities in social development, communication, and displays unusually strong obsessional interests, from an early age [35]. Asperger Syndrome (AS) has been proposed as a variant of autism, in children with normal or high IQ, who develop speech on time. Today, approximately 1 in 200 children have one of the ‘autistic spectrum conditions’, which include AS [36]. Autism spectrum conditions affect males far more often than females. In people with
Evidence for the extreme male brain theory
Initial tests of this theory are proving positive 41., 42.. Some of the convergent lines of evidence are summarised here.
The Autism Spectrum Quotient (AQ)
Males in the general population score higher on the AQ than do females, and people with AS or high-functioning autism score highest of all [55].
Sexually dimorphic somatic markers
On measures of finger-length ratio, males tend to have a longer ring finger than their second finger, and people with autism or AS show this trait in a magnified form [56].
Early puberty
Males with autism have been reported to show precocious puberty, correlating with increased levels of testosterone [57].
Familiality of talent
Fathers and grandfathers (on both sides of the family) of
A key symptom explained
Phenomena that are unpredictable and less controllable (like people) leave individuals with autism either anxious or disinterested. Phenomena that are more predictable are highly attractive to them. When they are confronted with the unpredictable social world, they react by trying to impose predictability and ‘sameness’, trying to control people through tantrums and insistence on repetition. People with autism and AS have their greatest difficulties in the playground, in friendship, in intimate
Central coherence versus systemising
A rival theory of the non-social cognitive anomalies observed in autism is that individuals with autism suffer from ‘weak central coherence’ [61]. The systemising account suggests a different view: that people with autism or AS start their cognitive processing by focussing in on the most local details, as an attempted search for whether these might be ‘variables’ in a systemisable domain. This focus on local processing might appear to arise from a deficit in global processing, but from the
Conclusions and future research
The evidence presented in this article suggests that the male brain is characterised by Type S (where S > E), the female brain by Type E (where E > S), and that the autistic brain is an extreme of the male brain (S >> E). Referring back to Fig. 1, development of an autism spectrum condition means their brain type has shifted towards the lower right-hand quadrant. For males, it is a small shift, from Type S to extreme Type S. For females, the shift is bigger, from Type E to extreme Type S. What
Acknowledgements
The following agencies have supported my work during the writing of this article: the Medical Research Council (UK), the Three Guineas Trust, the Isaac Newton Trust, and the James S. McDonnell Foundation. I am grateful to Sally Wheelwright and Johnny Lawson for the development of Fig. 1.
References (63)
- et al.
Gender comparisons of preschoolers behavior and resource utilization in group problem-solving
Child Dev.
(1987) You Just Don't Understand: Women and Men in Conversation
(1990)- et al.
Sex differences in route learning
Pers. Indiv. Diff.
(1993) A full genome screen for autism with evidence for linkage to a region on chromosome 7q
Hum. Mol. Genet.
(1998)Another advanced test of theory of mind: evidence from very high functioning adults with autism or Asperger Syndrome
J. Child Psychol. Psychiatry
(1997)- Baron-Cohen, S. et al. The exact mind: empathising and systemising in autism spectrum conditions. In Handbook of...
The cognitive basis of a biological disorder: autism
New Sci.
(1995)Mindblindness: an Essay on Autism and Theory of Mind
(1995)The Two Sexes: Growing Apart, Coming Together
(1998)Sex differences in empathy and related behaviors
Psychol. Bull.
(1977)