From Bruce Denness
Contagious yawning may indeed be sparked by the action of mirror neurons as Chris Good suggests (24 January, p 54). But perhaps there is more to it than that.
Maybe a triggering yawn merely implants the idea of yawning, which then sparks an urge to yawn. I need only think about yawning to set myself off, rather than having to see someone else yawn first. In fact, I yawned twice while writing this.
Whitwell, Isle of Wight, UK
