Simon Baron-Cohen

• 1. Introduction

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  Sir Simon Baron-Cohen is a British clinical psychologist at the University of Cambridge who has studied autism since 1982. Across that career he has put forward three large theories about the condition. Each one took a decade or more to gather its main body of evidence. Each has also drawn serious objections, from fellow scientists and from autistic people themselves. This documentary asks what it means to be blind to another person's mind. It asks why autism is diagnosed more often in males. And it asks how a researcher can build a career on ideas that remain so hotly contested.

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• 2. Mindblindness

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  In 1985, Baron-Cohen was working at the Medical Research Council Cognitive Development Unit in London alongside two colleagues, Uta Frith and Alan Leslie. Together they put forward the theory of mind hypothesis to explain the social and communication difficulties seen in autism. Theory of mind is also called cognitive empathy. It is the brain's partly innate way of quickly making sense of social behaviour by attributing mental states to other people.

  The team tested the idea with the false belief test. A typical four-year-old can work out that another person holds a belief different from their own. Autistic children, on average, were delayed in this ability.

  In 1995, Baron-Cohen published the book Mindblindness, which gathered the experiments that followed. He also designed the reading the mind in the eyes test, often called the Eyes Test. He interpreted its results as evidence that autistic children may be blind to what the eyes reveal about a person's thoughts. A systematic scoping review in 2024 has questioned whether Eyes Test scores really measure theory of mind, despite how widely the test is used.

  His team also ran the first neuroimaging study of theory of mind in typical and autistic adults. They studied patients with acquired brain damage, and showed that lesions in the orbito- and medial-prefrontal cortex and the amygdala can impair theory of mind. They reported the first evidence of atypical amygdala function in autism during such tasks.

  In 2017, his team studied 80,000 genotyped people who had taken the Eyes Test. Small variations in the genetic code, called single nucleotide polymorphisms, partly explained individual differences in scores. That was evidence that cognitive empathy is partly heritable. The National Institutes of Health went on to recommend the Eyes Test as a core measure for assessing social cognition under its Research Domain Criteria.

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• 3. Empathy and Systems

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  In 2003, Baron-Cohen set two human drives side by side and called the result the empathizing-systemizing theory. Empathizing has two parts. Cognitive empathy is imagining what someone else thinks or feels. Affective empathy is responding with a fitting emotion to what they think or feel.

  Systemizing is the drive to analyse or build rule-based systems in order to understand how things work. A system, in his definition, is anything that follows if-and-then patterns or rules.

  The theory argues that typical females on average score higher on empathizing than on systemizing, which he calls brain type E. Typical males on average show the reverse, brain type S. Autistic people are predicted to sit at the extreme end of the typical male pattern.

  A 2018 online study of 600,000 non-autistic people and 36,000 autistic people confirmed these predictions. A meta-analysis of 34 studies involving 1.2 million people agreed, and found that autistic people on average are hyper-systemizers.

  Genetics added a further strand. Working with the personal genomics company 23andMe, his team studied 56,000 genotyped people who had taken the Systemizing Quotient. Common genetic variants linked to systemizing overlapped with those linked to autism. Baron-Cohen concluded that the genetics of autism includes genes tied to disability, and also genes tied to talent in pattern recognition and in understanding how things work.

  He carried the argument into his 2020 book The Pattern Seekers. There he explores the idea that if-and-then hyper-systemizing is the basis of invention. He celebrates how autistic people played a key role in the evolution of human invention.

  The sex difference built into the theory raised a further question, about why autism is more common in males.

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• 4. Hormones Before Birth

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  In 1997, Baron-Cohen established the Cambridge Child Development Project, a longitudinal study following the children of 600 women who had undergone amniocentesis during pregnancy. His 2004 book Prenatal Testosterone in Mind, published by MIT Press, set out the prenatal sex steroid theory of autism. He proposed it to explain why autism is more common in males.

  The project showed, for the first time in humans, that normal variation in testosterone in the amniotic fluid relates to differences in later brain and behavioural development. In typical children, higher prenatal testosterone went with less eye contact and slower vocabulary growth. It also went with weaker social relationships, lower theory of mind performance and lower scores on the empathy quotient.

  The relationship ran the other way for other measures. Scores on the embedded figures test, which gauges attention to detail, rose with prenatal testosterone. So did scores on the Systemizing Quotient, measures of narrow interests and the number of autistic traits. The team also conducted the first human neuroimaging studies of grey matter volumes and brain activity linked to prenatal testosterone.

  To test the theory properly, Baron-Cohen needed a far larger sample. Autism occurs in only 3% of the population. So in 2015 he began a collaboration with the Danish Biobank, which holds over 20 thousand stored amniotic fluid samples. He linked them to later autism diagnoses through the Danish Psychiatric Register. Children later diagnosed as autistic had been exposed to elevated prenatal testosterone, and to elevated delta-4 sex steroid precursors of testosterone. In 2020 he tested the same cohort for prenatal estrogens and again found them elevated in pregnancies that led to autism.

  Other clues came from studies after birth. Autistic adults have elevated circulating androgens in their blood. In autistic women, the brain is masculinized in both grey and white matter volume. An independent animal model showed that elevated prenatal testosterone during pregnancy leads to reduced social interest in the offspring.

  Polycystic ovary syndrome is a medical condition caused by elevated prenatal testosterone. Baron-Cohen's group found that women with it have significantly higher odds of having an autistic child. Studies in Sweden, Finland and Israel replicated this, in line with the finding that mothers of autistic children themselves have elevated sex steroid hormones.

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• 5. Measures and Tools

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  In 2001, Baron-Cohen developed the autism-spectrum quotient, a set of 50 questions that counts how many autistic traits a person has. It was one of the first measures to show that autistic traits run right through the general population, with autistic people simply scoring higher on average. Multiple studies link high scores to scientific and mathematical talent, which suggests a shared mechanism such as strong systemizing. The quotient has been used in hundreds of studies, including one of half a million people, which showed robust sex differences and higher scores among those working in STEM.

  In 2006, he proposed the assortative mating theory. It holds that when two people with the systemizing brain type have a child, that child is more likely to be autistic. One piece of evidence came from a population study in Eindhoven, an IT hub, where autism rates are twice as high as in other Dutch cities. He also found that both mothers and fathers of autistic children score above average on attention to detail, a prerequisite for strong systemizing.

  His applied research has pointed to failures of support. He found that autistic people are being failed by the criminal justice system. They also have higher rates of suicidality, higher rates of postnatal depression, and higher rates of mental and physical health conditions.

  His team has built practical tools as well. Mindreading was designed for use in special education. The Transporters is an animation series that teaches emotion recognition to younger autistic children. They also ran the first clinical trial of lego therapy in the UK, and found that autistic children improved their social skills afterwards. Mindreading and The Transporters were both nominated for British Academy of Film and Television Arts awards, in 2002 and 2007.

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• 6. Critics and Praise

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  Cordelia Fine, the neuroscientist Gina Rippon and Lise Eliot are among the feminist scientists who have questioned his extreme male brain theory of autism. They have charged that it amounts to neurosexism. Baron-Cohen has defended the study of sex differences. He clarifies that such differences apply only to averages between groups of males and females. He agrees that it would be sexist and unacceptable to prejudge an individual by gender, since a person's mind may not be typical of their gender.

  A second line of criticism targets who he studies. Critics argue that his focus on autistic people without intellectual or learning disability limits how far his findings can be generalised. He replies that strong systemizing is seen even among those with a learning disability.

  The theory of mind deficit hypothesis has faced criticism from some people in the autism community and from some researchers. Baron-Cohen notes that many studies have replicated the group-level, on-average differences, despite how varied autistic people are in empathy and theory of mind. Some in the autism community argue that non-autistic people are just as blind to the mental states of autistic people as the reverse. This is known as the double empathy problem.

  Baron-Cohen and colleagues responded with a recent article identifying 23 meta-analyses of theory of mind in autism, drawn from 40 years of studies. In 22 of the 23, autistic people scored statistically lower than non-autistic people. They read this as showing that, on average, difficulty with theory of mind is one feature of autistic people.

  The reviews of his books are mixed. Spectrum News called his theory of mind work a landmark study. The Lancet described a man of extraordinary knowledge whose passionate advocacy for a more tolerant, diverse society shows a very human side to his science. The Guardian called his book The Essential Difference compelling and inspiring, while a review in Phenomenology and the Cognitive Sciences found it very disappointing. The New York Times chose The Pattern Seekers as an Editor's Choice. It also wrote that in The Science of Evil, published in the US with the subtitle On Empathy and the Origins of Human Cruelty, an award-winning psychologist had unveiled a simple but persuasive hypothesis for a new way to think about evil.

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• 7. Family and Training

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  Simon Philip Baron-Cohen was born on the 15th of August 1958 into a Jewish family in London. He was the second son of Judith and Hyman Vivian Baron-Cohen. He has an elder brother, Dan Baron Cohen, and three younger siblings: a brother, Ash Baron-Cohen, and sisters Suzie and Liz.

  His cousins include the actor and comedian Sacha Baron Cohen and the composer Erran Baron Cohen. On his mother's side, his uncle was the Canadian racing driver and constructor David Greenblatt. His great-uncle was the endocrinologist Robert Benjamin Greenblatt, a field that would later sit close to his own work on hormones.

  His training began with a BA in human sciences at New College, Oxford. He then took an MPhil in clinical psychology at the Institute of Psychiatry, King's College London. He earned his PhD in psychology at University College London, where his doctoral research was done in collaboration with his supervisor, Uta Frith.

  In 1987, he married Bridget Lindley. They have three children.

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• 8. Roles and Honours

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  Baron-Cohen is professor of developmental psychopathology at the University of Cambridge. He directs the university's Autism Research Centre and is a Fellow of Trinity College. He is also a clinical psychologist, and he created the first diagnosis clinic in the UK for late autism diagnosis in adults.

  He is a Fellow of the British Psychological Society, the British Academy, the Academy of Medical Sciences, the Royal Society of Medicine, the International Society for Autism Research and the Association for Psychological Science. He is a Chartered Psychologist with the British Psychological Society and a Senior Investigator at the National Institute for Health and Care Research. He has chaired the Psychology Section of the British Academy.

  He serves as vice-president of the National Autistic Society in the UK. In 2012, he chaired the Guideline Development Group for adults with autism at the National Institute for Health and Care Excellence. He has been both vice-president and president of the International Society for Autism Research, and he was founding co-editor-in-chief of the journal Molecular Autism. In 2017, on World Autism Awareness Day, he gave the keynote lecture at the United Nations on autism and human rights.

  His prizes began early. The British Psychological Society awarded him the 1990 Spearman Medal, the 1993 May Davidson Award for Clinical Psychology and the 2006 Presidents' Award. The American Psychological Association gave him the McAndless Award. In 2012, he received honorary Doctor of Science degrees from Abertay University and from Roehampton University. In 2013, the Wissenschaftliche Gesellschaft Autismus-Spektrum gave him the Kanner-Asperger Medal as a Lifetime Achievement Award.

  He was knighted in the 2021 New Year Honours for services to people with autism. In 2023, the Medical Research Council gave him its Millennium Medal for his work on the prenatal sex steroid theory and his transformative contributions to autism. The most recent prize on that list is the 2026 Grawemeyer Award in Psychology.

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