A milestone research on autism: brain wiring, sex, hormones and cognitive empathy

1. Baron-Cohen S (2009) Autism: The empathizing-systemizing (E-S) theory. Ann N Y Acad Sci 1156:68–80. 

2. Baron-Cohen S, Knickmeyer RC, Belmonte MK (2005) Sex differences in the brain: Implications for explaining autism. Science 310:819–823.

3. http://www.pnas.org/content/early/2018/11/06/1811032115
Significance 
In the largest study to date of autistic traits, we test 10 predictions from the Empathizing–Systemizing (E-S) theory of sex differences and the Extreme Male Brain (EMB) theory of autism. We confirmed that typical females on average are more empathic, typical males on average are more systems-oriented, and autistic people on average show a “masculinized” profile. The strengths of the study are the inclusion of a replication sample and the use of big data. These two theories can be considered to have strong support. We demonstrate that D-scores (difference between E and S) account for 19 times the variance in autistic traits than do other demographic variables, including sex, underscoring the importance of brain types in autism.

Table 3.

Frequency distribution of brain types

Brain type	Control males, %	Control females, %	Autistic males, %	Autistic females, %
Extreme Type E	0.75	2.89	0.30	0.93
Type E	23.88	40.01	13.37	22.20
Type B	30.99	29.81	23.92	27.03
Type S	40.24	25.59	50.98	42.29
Extreme Type S	4.15	1.69	11.43	7.55

• This table reports the frequency of the control and case populations based on brain types. All numbers are in percentages. n = 241,355 (male controls), 393,600 (female controls), 18,188 (male cases), and 18,460 (female cases). http://www.pnas.org/content/early/2018/11/06/1811032115/tab-figures-data

Finally, this research shows that brain wiring and its consequences are at the root of autism. Secondly, it is the influence of sex hormones that drive the brain wiring which is determinant for autism. Thirdly, the conceptual framework that Baron-Cohen elaborated in previous papers is of paradigmatic significance to better understand both normal and autistic brains. A lethal blow to other unfounded theories of autism: especially the psychoanalytic one.