Contagious yawning: developmental and comparative perspectives

Contagious yawning (i.e., yawning triggered by perceiving others’ yawning) is a well-documented phenomenon, but the mechanism underlying it is still unclear. In this chapter, I review the current evidence about (a) developmental studies with typically and atypically developing population and (b) comparative studies in non-human animals. Developmental studies have revealed that contagious yawning is disturbed in individuals with Autism Spectrum Disorders, suggesting that contagious yawning may share a developmental basis with the capacity for theory of mind. Comparative studies have suggested that contagious yawning can be observed in non-primate species such as domestic dogs. As dogs are known to have exceptional skills in communicating with humans, it has also been suggested that contagious yawning may be related to the capacity for social communication. These results from developmental and comparative studies are consistent with the claim that the mechanism underlying contagious yawning relates to the capacity for empathy. Acknowledgements The author was supported by a Research Fellowship (RES-063–27–0207) from the UK Economic and Social Research Council. Introduction Contagious yawning (i.e., yawning triggered by perceiving others’ yawning) is a well-documented phenomenon. Previous studies have consistently reported that, in a naturalistic or controlled experimental context, 45-60 % of human adults yawn when they observe, hear or imagine others’ yawning . It is not due to common environmental factors between two yawners such as temperature, lighting or the lack of oxygen, because pre-recorded yawning video clips and sounds can also induce contagious yawning . Recently, this phenomenon has been widely sought after in the field of developmental and comparative cognitive sciences. Apart from the intrinsic interest in this well-known but puzzling phenomenon, this is mainly because it is apparently empathetic: the observation of the emotional or physiological status of