As she observes, obsessional interests and repetitive behaviours would allow someone to practice, albeit inadvertently, whichever skill they were obsessed by. Malcolm Gladwell, in a book called “Outliers” which collated research done on outstanding people, suggested that anyone could become an expert in anything by practising for 10,000 hours. It would not be hard for an autistic individual to clock up that level of practice for the sort of skills, such as mathematical puzzles, that many neurotypicals would rapidly give up on.

Many, but not all. Dr Happé has drawn on a study of almost 13,000 individual twins to show that childhood talent in fields such as music and art is often associated with RRBIs, even in those who are not diagnosed as classically autistic. She speculates that the abilities of savants in areas that neurotypicals tend to find pointless or boring may result from an ability to see differences where a neurotypical would see only similarities. As she puts it, “the child with autism who would happily spend hours spinning coins, or watching drops of water fall from his fingers, might be considered a connoisseur, seeing minute differences between events that others regard as pure repetition.”