The BPS Research Digest reports that children with autism are seemingly 'immune' to contagious yawning - perhaps as a result of their reduced social awareness.

Seeing someone yawn, or indeed, just thinking about someone else yawning, makes us more likely to do the same. For example, this article may well be enough to trigger a yawn in some people.

One of the three key aspects of autism is a difficulty with social interaction (the other two being difficulties with certain types of abstract thinking and a restricted or repetitive range of interests or behaviours).

So a group of researchers, led by psychologist Dr. Atsushi Senju, wondered whether children with autism might be less susceptible to yawn contagion.

They came up with the 'I wish I'd thought of that' idea of showing videos of people yawning to groups of typically developing children, and children with a diagnosis of autism.