A link between heightened intelligence and autism has been suspected by scientists based on empirical evidence, and now genetic screening seems to confirm this assumption. People carrying genes that put people at risk of developing autism scored higher on intelligence scores than those who lacked the genes. This held true, however, for people carrying the genes but who didn’t develop autism.

Popular culture often portrays autistic individuals as able to solve incredibly complex problems, despite their inability to relate with other people socially or emotionally. Rain man staring Dustin Hoffman and Tom Cruise first comes to mind. While this is true to an extent, autistic savants represent a minority. Almost 70% of autistic individuals have intellectual disabilities, besides social awkwardness. Granted, that still leaves a impressive number of autistic persons who have an above average non-verbal intelligence. This has always puzzled researchers.

Far from being resolved, researchers think the same genes that cause autism also improve cognitive abilities. A team at University of Edinburgh, UK and University of Queensland, Australia recruited 10,000 people from the general population, had their DNA sequenced and were tested for cognitive abilities. One average, those people who had genes whose traits are associated with autism, but never developed autism, scored slightly better on cognitive tests. Similar results were found when the same tests were carried out on  921 adolescents who were part of the Brisbane Adolescent Twin Study, as reported in Molecular Psychiatry.

Dr Toni-Kim Clarke, of the University of Edinburgh’s Division of Psychiatry, who led the study, said: “Our findings show that genetic variation which increases risk for autism is associated with better cognitive ability in non-autistic individuals. As we begin to understand how genetic variants associated with autism impact brain function, we may begin to further understand the nature of autistic intelligence.”

Professor Nick Martin, of the Queensland Institute for Medical Research, said: “Links between autism and better cognitive function have been suspected and are widely implied by the well-known “Silicon Valley syndrome” and films such as “Rain Man” as well as in popular literature. This study suggests genes for autism may actually confer, on average, a small intellectual advantage in those who carry them, provided they are not affected by autism.”