Sir Simon Philip Baron-Cohen (born 15 August 1958) is a British clinical psychologist and professor of developmental psychopathology at the University of Cambridge. He is the director of the university's Autism Research Centre and a Fellow of Trinity College.
Baron-Cohen has worked in autism research for over 40 years, starting in 1982. In 1985, Baron-Cohen formulated the mindblindness theory of autism, the evidence for which he collated and published in 1995. In 1997, he formulated the prenatal sex steroid theory of autism, the key test of which was published in 2015. In 2003, Baron-Cohen formulated the empathising-systemising (E-S) theory of autism and typical sex differences, the key test of which was published in 2018.
Baron-Cohen has also made major contributions to both basic and applied research in autism, and to the field of synaesthesia. He was knighted in the 2021 New Year Honours for services to people with autism. In 2023, Baron-Cohen was awarded the Medical Research Council (MRC) Millennium Medal. He is the 2026 recipient of the Grawemeyer Award in Psychology.
Early life and education Baron-Cohen was born into a Jewish family in London, the second son of Judith and Hyman Vivian Baron-Cohen. Baron-Cohen has an elder brother, Dan Baron Cohen, and three younger siblings: brother Ash Baron-Cohen and sisters Suzie and Liz. His cousins include actor and comedian Sacha Baron Cohen and composer Erran Baron Cohen.
His maternal uncle was Canadian racing driver and constructor David Greenblatt. His maternal great-uncle was endocrinologist Robert Benjamin Greenblatt.
Baron-Cohen completed a BA in human sciences at New College, Oxford, and an MPhil in clinical psychology at the Institute of Psychiatry, King's College London. He received a PhD in psychology at University College London; Baron-Cohen's doctoral research was in collaboration with his supervisor, Uta Frith.
Career Baron-Cohen is professor of developmental psychopathology at the University of Cambridge in the United Kingdom. He is the director of the university's Autism Research Centre and a Fellow of Trinity College.
He is a Fellow of the British Psychological Society (BPS), 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 BPS Chartered Psychologist and a Senior Investigator at the National Institute for Health and Care Research (NIHR).
Baron-Cohen serves as vice-president of the National Autistic Society (UK), and was the 2012 chair of the National Institute for Health and Care Excellence (NICE) Guideline Development Group for adults with autism. He has served as vice-president and president of the International Society for Autism Research (INSAR). Baron-Cohen was the founding co-editor-in-chief of the journal Molecular Autism.
He was the chair of the Psychology Section of the British Academy. As a clinical psychologist he created the first clinic in the UK for late adult autism diagnosis.
Baron-Cohen gave the keynote lecture on the topic of "Autism and Human Rights" at the United Nations on World Autism Awareness Day in 2017.
Research The mindblindness theory of autism In 1985, while he was member of the MRC Cognitive Development Unit (CDU) in London, Baron-Cohen and his colleagues Uta Frith and Alan Leslie formulated the "theory of mind" (ToM) hypothesis, to explain the social-communication difficulties in autism. ToM (also known as "cognitive empathy") is the brain's partially innate mechanism for rapidly making sense of social behavior by effortlessly attributing mental states to others, enabling behavioral prediction and social communication skills. They confirmed this using the false belief test, showing that a typical four-year-old child can infer another person's belief that is different to their own, while autistic children on average are delayed in this ability.
Baron-Cohen's 1995 book, Mindblindness summarized his subsequent experiments in ToM and the disability in ToM in autism. Using the "reading the mind in the eyes test" (or "Eyes Test") he designed, Baron-Cohen interpreted evidence that may suggest that autistic children are blind to the mentalistic significance of the eyes and show difficulties in advanced ToM.
He conducted the first neuroimaging study of ToM in typical and autistic adults, and studied patients with acquired brain damage, demonstrating lesions in the orbito- and medial-prefrontal cortex and amygdala can impair ToM. Baron-Cohen also reported the first evidence of atypical amygdala function in autism during ToM. In 2017, his team studied 80,000 genotyped individuals who took the eyes test. Baron-Cohen found single nucleotide polymorphisms (SNPs) partly contribute to individual differences on this dimensional trait measure on which autistic people show difficulties. This was the evidence that cognitive empathy/ToM is partly heritable. The National Institutes of Health recommended Baron-Cohen's eyes test as a core measure that should be used as part of the Research Domain Criteria (RDOC) for assessing social cognition.
Empathizing-systemizing (E-S) theory In 2003, Baron-Cohen developed the empathizing-systemizing (E-S) theory. Empathizing includes both cognitive empathy (imagining what someone else is thinking or feeling) and affective empathy (responding with an appropriate emotion to what someone is thinking or feeling). Systemizing is the drive to analyse or construct rule-based systems to understand how things work. A system is defined as anything that follows if-and-then patterns or rules.
The E-S theory argues that typical females on average score higher on empathizing relative to systemizing (they are more likely to have a brain of type E), and typical males on average score higher on systemizing relative to empathizing (they are more likely to have a brain of type S). Autistic people are predicted to score as an extreme of the typical male (they are more likely to have a brain of type S or extreme type S). These predictions were confirmed in a 2018 online study of 600,000 non-autistic people and 36,000 autistic people. This has been confirmed in a large meta-analysis of 34 studies involving 1.2 million people. This also confirmed that autistic people on average are "hyper-systemizers". In 2026, his group showed 130 newborns, on average 33 hours old, a video of a human face and a video of a moving Newton's cradle. Girls devoted a greater proportion of their looking time to the face than boys did, while the two sexes did not differ in how long they looked at either video in absolute terms.
Working with the personal genomics company 23andMe, Baron-Cohen's team studied 56,000 genotyped individuals who had taken the Systemizing Quotient. He and his colleagues found that the common genetic variants associated with systemizing overlapped with the common genetic variants associated with autism. Baron-Cohen concluded that the genetics of autism not only includes genes associated with disability, but also include genes associated with talent in pattern recognition and understanding how things work. In his 2020 book The Pattern Seekers, Baron-Cohen explored the idea that 'if-and-then' hyper-systemising is the basis of invention, and celebrates how autistic people played a key role in the evolution of human invention.
Prenatal neuroendocrinology In his 2004 book Prenatal Testosterone in Mind (MIT Press), Baron-Cohen put forward the prenatal sex steroid theory of autism. He proposed this theory to understand why autism is more common in males. Using the Cambridge Child Development Project that Baron-Cohen established in 1997, a longitudinal study studying children of 600 women who had undergone amniocentesis in pregnancy, he followed these children postnatally. This study demonstrated, for the first time in humans, how normative variation in amniotic prenatal testosterone levels correlates with individual differences in typical postnatal brain and behavioral development. Baron-Cohen's team discovered that in typical children, amount of eye contact, rate of vocabulary development, quality of social relationships, theory of mind performance, and scores on the empathy quotient are all inversely correlated with prenatal testosterone levels. In contrast, they found that scores on the embedded figures test (of attention to detail), on the systemizing quotient (SQ), measures of narrow interests, and number of autistic traits are positively correlated with prenatal testosterone levels. Within this study, Baron-Cohen's team conducted the first human neuroimaging studies of brain grey matter regional volumes and brain activity associated with prenatal testosterone.
But to really test the theory, Baron-Cohen needed a much larger sample than his Cambridge Child Development Project, autism only occurs in 3% of the population. So, in 2015, he set up a collaboration with the Danish Biobank which has stored over 20 thousand amniotic fluid samples, which Baron-Cohen linked to later diagnosis of autism via the Danish Psychiatric Register. He tested the prenatal androgens and found that children later diagnosed as autistic were exposed to elevated levels of prenatal testosterone, and the Δ4 sex steroid precursors to prenatal testosterone. In 2020, Baron-Cohen tested the same cohort's levels of exposure to prenatal estrogens and again found these were elevated in pregnancies that resulted in autism.
Other clues for the theory came from his postnatal hormonal studies which found that autistic adults have elevated circulating androgens in serum and that the autistic brain in women is 'masculinized' in both grey and white matter brain volume. An independent animal model showed that elevated prenatal testosterone during pregnancy leads to reduced social interest in the offspring. Baron-Cohen's group also studied the rate of autism in offspring of mothers with polycystic ovary syndrome (PCOS), a medical condition caused by elevated prenatal testosterone. He found that in women with PCOS, the odds of having a child with autism are significantly increased. This has been replicated in three other countries (Sweden, Finland, and Israel) and is in line with the finding that mothers of autistic children themselves have elevated sex steroid hormones. These novel studies provide evidence of the role of prenatal hormones, interacting with genetic predisposition, in the cause of autism. In 2026, Baron-Cohen and colleagues reviewed 25 years of work on the theory in Nature Human Behaviour, concluding that evidence from prenatal androgens and estrogens, from genetics and from stem-cell-derived neural organoids supports it.
Other contributions In 2006, Baron-Cohen proposed the assortative mating theory which states that if individuals with a systemizing or "type S" brain type have a child, the child is more likely to be autistic. Pdf. Now in One piece of evidence for this theory came from his population study in Eindhoven, where autism rates are twice as high in that city which is an IT hub, compared to other Dutch cities. He also found both mothers and fathers of autistic children score above average on tests of attention to detail, a prerequisite for strong systemizing.