Dogs’ capacity to ‘catch’ human yawns has recently attracted the attention of researchers in the field of animal cognition. Following recent studies suggesting that contagion yawning in humans, and some other primates, is empathy-related, some authors have considered the possibility that the same mechanism may underlie contagious yawning in dogs. To date, however, no positive evidence has been found, and more parsimonious hypotheses have been put forward. The present study explored the ‘contagion-only’ hypothesis by testing whether the mere sound of a human yawn can be sufficient to elicit yawning in dogs, in a way that is unaffected by social–emotional factors. Unexpectedly, results showed an interesting interplay between contagion and social effects. Not only were dogs found to catch human yawns, but they were also found to yawn more at familiar than unfamiliar yawns. Although not allowing for conclusive inferences about the mechanisms underlying contagious yawning in dogs, this study provides first data that renders plausible empathy-based, emotionally connected, contagious yawning in these animals.
Canis domesticusContagion Empathy Social modulation Yawning
The authors are grateful to all the owners of the dogs who volunteered to participate in the present study. Also the authors want to thank Claudio Tennie for his valuable suggestions as well as three anonymous referees for their valuable comments on a previous version of this manuscript. Fundação para a Ciência e a Tecnologia funded the participation of Karine Silva (FCT-SFRH/BPD/37017/2007).