Testing the Empathizing-Systemizing theory of sex differences and the Extreme Male Brain theory of autism in half a million people.


Change log
Authors
Greenberg, David M 
Warrier, Varun 
Abstract

The Empathizing-Systemizing (E-S) theory of typical sex differences suggests that individuals may be classified based on empathy and systemizing. An extension of the E-S theory, the Extreme Male Brain (EMB) theory suggests that autistic people on average have a shift towards a more masculinized brain along the E-S dimensions. Both theories have been investigated in small sample sizes, limiting their generalizability. Here we leverage two large datasets (discovery n = 671,606, including 36,648 autistic individuals primarily; and validation n = 14,354, including 226 autistic individuals) to investigate 10 predictions of the E-S and the EMB theories. In the discovery dataset, typical females on average showed higher scores on short forms of the Empathy Quotient (EQ) and Sensory Perception Quotient (SPQ), and typical males on average showed higher scores on short forms of the Autism Spectrum Quotient (AQ) and Systemizing Quotient (SQ). Typical sex differences in these measures were attenuated in autistic individuals. Analysis of "brain types" revealed that typical females on average were more likely to be Type E (EQ > SQ) or Extreme Type E and that typical males on average were more likely to be Type S (SQ > EQ) or Extreme Type S. In both datasets, autistic individuals, regardless of their reported sex, on average were "masculinized." Finally, we demonstrate that D-scores (difference between EQ and SQ) account for 19 times more of the variance in autistic traits (43%) than do other demographic variables including sex. Our results provide robust evidence in support of both the E-S and EMB theories.

Description
Keywords
autism, big data, empathy, sex differences, systemizing, Adolescent, Adult, Autistic Disorder, Brain, Empathy, Female, Humans, Male, Psychological Tests, Sex Factors, Systems Theory, Young Adult
Journal Title
Proc Natl Acad Sci U S A
Conference Name
Journal ISSN
0027-8424
1091-6490
Volume Title
115
Publisher
Proceedings of the National Academy of Sciences
Sponsorship
National Institute for Health Research (NIHR) (via Cambridgeshire and Peterborough NHS Foundation Trust (CPFT) (unknown)
Autism Research Trust (unknown)
Templeton World Charity Foundation (TWCF) (TWCF0138/AB89)
Medical Research Council (G0600977)
This study was supported by the Medical Research Council (MRC), the Wellcome Trust, the Templeton World Charity Foundation, the Autism Research Trust, and the National Institute of Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care-East of England (CLAHRC-EoE). The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health. The authors also received funding from the Innovative Medicines Initiative 2 Joint Undertaking (JU) under grant agreement No 777394. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and EFPIA and Autism Speaks, Autistica, SFARI.