‘Male brain’ autism theory backed by biggest-ever study

Theories that suggest men have a natural tendency towards autism have been supported by a major study exploring psychological sex differences.

Around half a million people, including more than 36,000 diagnosed with autism, underwent tests designed to measure traits such as empathy, emotional responses and systemic thinking.

Researchers found that women on average had higher empathy scores than men, while men scored higher for systemising and traits associated with autism such as not being good at recognising and responding to other people’s thoughts and feelings.

In people with autism, the test results were generally “masculinised”.

Compared with the typical population, autistic individuals had higher scores for systemising and autistic traits and lower scores for empathy.

Systemising refers to a natural preference for rule-based, orderly systems, and a drive to analyse.

The study also found that people working in STEM (science, technology, engineering and mathematics) fields had higher autistic scores on average than those in non-STEM occupations.

Dr Varun Warrier, a member of the Cambridge University team, said: “These sex differences in the typical population are very clear.

“We know from related studies that individual differences in empathy and systematising are partly genetic, partly influenced by our prenatal hormonal exposure, and partly due to environmental experience.

“We need to investigate the extent to which these observed sex differences are due to each of these factors, and how these interact.”

The findings are reported in the journal Proceedings of the National Academy of Sciences.

The study, the largest of its kind ever conducted, provides evidence supporting two long-standing theories on psychological gender differences and autism.

The Empathasing-Systemising theory predicts that women on average will score higher than men in tests of empathy, the ability to recognise what another person is thinking or feeling, and appropriate emotional responses. It also predicts that men on average will score higher on tests of systemising.

The Extreme Mail Brain theory holds that both men and women with autism are good systemisers but less able to empathise than the general population. It proposes that autism is related to over-exposure to the male hormone testosterone in the womb.

Professor Simon Baron-Cohen, director of the Autism Research Centre at Cambridge University, who came up with the theories nearly two decades ago, said: “This research provides strong support for both theories.

“This study also pinpoints some of the qualities autistic people bring to neurodiversity. They are, on average, strong systemisers, meaning they have excellent pattern-recognition skills, excellent attention to detail, and an aptitude in understanding how things work.

“We must support their talents so they achieve their potential – and society benefits too.”

The researchers pointed out that lack of empathy did not mean autistic people were psychopaths.

While struggling with “cognitive” empathy – the ability to recognise thoughts and feelings – they still possessed “affective” empathy, which involves caring about what happens to other people.