In humans yawning can be triggered both physiologically as well as psychologically (i.e., spontaneous and contagious yawns), and it is the distinct manifestation of these 2 yawn types that has led researchers to traditionally study them independently. However, evolution produces adaptations that are constrained by and build upon existing architecture, and since contagious yawning is a derived f...

Although we yawn each and every day, most people have little understanding of why we do it. In fact, the function of yawning has remained mysterious for centuries, even among scientists, and this has only changed quite recently. Contrary to what people have believed for a long time, it is now understood that yawns have nothing to do with breathing or the amount of oxygen we are taking in. Inste...

Contagious yawning is a common, but poorly understood phenomenon. We hypothesized that contagious yawning is part of a more general phenomenon known as mental state attribution (i.e. the ability to inferentially model the mental states of others). To test this hypothesis we compared susceptibility to contagiously yawn with performance on a self-face recognition task, several theory of mind stor...

The recent interest in contagious yawning has raised several challenges as the varied methods of testing have left some unresolved issues. We do not know how differences in key variables affect the observed rates of yawning, and we highlight these as being in need of direct testing. Different researchers analyze their results differently, and we make some recommendations for more rigorous, thor...

Various studies and researchers have proposed a link between contagious yawning and empathy, yet the conceptual basis for the proposed connection is not clear and deserves critical evaluation. Therefore, we systematically examined the available empirical evidence addressing this association; i.e., a critical review of studies on inter-individual differences in contagion and self-reported values...

A thirteen-year-old patient is presented, to demonstrate how the active analysis of nonverbal expressive behavior, in this case yawning, was of value in understanding and treating a youngster who, because he was so withdrawn, would not otherwise have been amenable to the standard one-to-one psychotherapeutic approach. In discussing the clinical material, the literature concerning nonverbal expr...