title: The "Reading the Mind in the Eyes" Test: Complete Absence of Typical Sex Difference in ~400 Men and Women with Autism.
abstract: The "Reading the Mind in the Eyes" test (Eyes test) is an advanced test of theory of mind. Typical sex difference has been reported (i.e., female advantage). Individuals with autism show more difficulty than do typically developing individuals, yet it remains unclear how this is modulated by sex, as females with autism have been under-represented. Here in a large, non-male-biased sample we test for the effects of sex, diagnosis, and their interaction. The Eyes test (revised version) was administered online to 395 adults with autism (178 males, 217 females) and 320 control adults (152 males, 168 females). Two-way ANOVA showed a significant sex-by-diagnosis interaction in total correct score (F(1,711) = 5.090, p = 0.024, ηp2 = 0.007) arising from a significant sex difference between control males and females (p < 0.001, Cohen's d = 0.47), and an absence of a sex difference between males and females with autism (p = 0.907, d = 0.01); significant case-control differences were observed across sexes, with effect sizes of d = 0.35 in males and d = 0.69 in females. Group-difference patterns fit with the extreme-male-brain (EMB) theory predictions. Eyes test-Empathy Quotient and Eyes test-Autism Spectrum Quotient correlations were significant only in females with autism (r = 0.35, r = -0.32, respectively), but not in the other 3 groups. Support vector machine (SVM) classification based on response pattern across all 36 items classified autism diagnosis with a relatively higher accuracy for females (72.2%) than males (65.8%). Nevertheless, an SVM model trained within one sex generalized equally well when applied to the other sex. Performance on the Eyes test is a sex-independent phenotypic characteristic of adults with autism, reflecting sex-common social difficulties, and provides support for the EMB theory predictions for both males and females. Performance of females with autism differed from same-sex controls more than did that of males with autism. Females with autism also showed stronger coherence between self-reported dispositional traits and Eyes test performance than all other groups.
authors: Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; CLASS Clinic, Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom.
authors: Simon
authors: S
authors: Baron-Cohen
authors: Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom.
authors: Daniel C
authors: DC
authors: Bowen
authors: Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom.
authors: Rosemary J
authors: RJ
authors: Holt
authors: Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom.
authors: Carrie
authors: C
authors: Allison
authors: Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Department of Psychology, University of Edinburgh, Edinburgh, United Kingdom.
authors: Bonnie
authors: B
authors: Auyeung
authors: Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; Department of Psychology and Center of Applied Neuroscience, University of Cyprus, Nicosia, Cyprus.
authors: Michael V
authors: MV
authors: Lombardo
authors: Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom.
authors: Paula
authors: P
authors: Smith
authors: Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom; CLASS Clinic, Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, United Kingdom; Centre for Addiction and Mental Health and Department of Psychiatry, University of Toronto, Toronto, Canada; Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan.
authors: Meng-Chuan
authors: MC
authors: Lai
mesh_terms: D000328:Adult; D000067877:Autism Spectrum Disorder / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D011932:Reading; D012727:Sex Characteristics; D060388:Support Vector Machine