Why aren’t yawns contagious in autism?

By Jesslee Cuizon via Flickr

A nice little study in the Sep/Oct issue of Child Development found that children with an autism diagnosis are less susceptible to contagious yawning than “neurotypical” children. My first reaction was happiness that someone is studying this. Contagious yawning is one of those pop-neuropsychiatric phenomena that I am likely to be asked about at a cocktail party, and until now I had nothing interesting to say about it. Another example is the age-old question of why we can’t tickle ourselves, which itself will be the topic of a future post in these pages. Most people’s first reaction to the contagious yawn/ASD study is likely to be “so what?”

If you think this study is an example of frivolous research, you may be even more upset to know that this is not the first study to address this issue. In the previous work, children were observed while watching a video in which people occasionally yawned: again, autistic kids yawned less than the controls. The new study used live interactions, and also included an observational study of typical development that found that contagious yawning begins around age 4.

So why on earth do we care about this? The hypothesis of the investigators, and I think they’re right, is that contagious yawning is a manifestation of the very basic mechanisms of empathy and socialization, which we know are impaired in autism. It’s well-known that in conversations we tend to mirror our conversation partner to a degree that usually correlates to our attachment to and interest in them. Many self-help books on sales and persuasion encourage deliberately mirroring people to exploit this mechanism and increase the trust and comfort level of your acquaintance (or target, as the case may be). Yawning is also a lot easier to observe and quantify than empathy. Even better, contagious yawning is something that can be tested in an fMRI or with other functional imaging. If we believe that children with autism have a deficit in this basic function, and we can find out how and where this function develops in the brain, then we just might learn something interesting about the neurobiology and development of autism. In fact, the authors go so far as to suggest certain brain areas are involved, the insula and anterior cingulate cortex to be precise. This isn’t the first time these areas have been implicated in autism. In fact, they seem to be implicated in just about everything. But it’s nice to accumulate any concrete evidence we can get.