Autistic children are less sensitive to the movements of living things

For any animal, it pays to be able to spot other animals in order to find mates and companions and to avoid predators. Fortunately, many animals move in a distinct way, combining great flexibility with the constraints of a rigid skeleton - that sets them apart from inanimate objects like speeding trains or flying balls. The ability to detect this "biological motion" is incredibly important. Chicks have it. Cats have it. Even two-day-old babies have it. But autistic children do not.