Le bâillement : quand, comment, pourquoi?

Stretching and yawning (the association has gone identified as pandiculation) are neglected features among categories of maintenance behaviour. Arising in the common ancestors of all vertebrates, systematic and coordinated pandiculations occur in a compound pattern of almost identical general form among them, during the three recurrent behaviours of sleep-wakefulness, feeding and reproduction. This kinesis appears as one undirected response to an inner stimulation, underlying the homeostasis of these three behaviours. By explaining the specific regulatory strategies and the neural networks involved, it is proposed that yawning is a part of introspectiveness by its capacity to increase wakefulness and self-awareness. Hominids have the unique capacity to be receptive to the contagiousness of yawning. Yawning appears to trigger a sort of social coordination function (arousal synchrony) and reflects the capacity to unconsciously, automatically be influenced by the behaviour of others, supporting the hypothesis that contagious yawning shares the neural networks involved in empathy.