We all have a group of friends or relatives who make up our social circus and keep us entertained and happy. Our ingroup in psychological terminology, the members of which we feel empathy for and we laugh or cry with them. Other groups that we don’t know are out groups and here our empathy can be pretty thin.Empathy makes actions like laughing or crying a great deal more infectious. Hence, if we are a stand-up comedian or a politician – sorry for repeating myself just then– it is wise to stack the audience with some friends.
Yawning too is infectious, as I have found to my cost when lecturing. The student classmates are an ingroup, and yawns can spread through my audience like wildfire. However, the yawning contagion isn’t confined to familiars with humans, strangers can catch it too.
So it is with dogs. The infectiousness of yawning goes wider than the ingroup. Dog empathy goes wider that just their friends. But then many dogs seem to be optimists and expect me to make a fuss of them without us having been formally introduced.
So what about Chimpanzees? Well Campbell and de Waal of Emory U have just published a study (1). Here a group of chimpanzees were shown videos of familiars and unfamiliars yawning. Although they were very interested in the unfamiliar chimps and trying to see if they checked with someone in a rogues gallery, they didn’t catch as many yawns as when they saw videos of their friends and relations yawning.
Note though that yawns from any of the chimp body were infectious. In an earlier paper (2) Campbell et al reported that chimps also caught yawns from 3-D chimp avatars. Must have been a pretty bad movie if even the avatars were yawning.
2. Campbell et al.,Proc. of the Roy. Soc., Biological Sciences 276: 4255–4259
