Psychologists’ puzzlement at why yawning is contagious is at an end. A new study in Cognitive Brain Research finds that it is correlated with people’s empathic ability. The 40-60% of who do not catch yawns appear to be the ones with the least ability to put themselves in others’ shoes in other regards.

Contrary to the folk wisdom that it precipitates a deep breath to counteract oxygen decrement, yawning does not appear to have a physiological function. It may have evolved primarily as a social clue —

Contagious yawning may have helped our ancestors coordinate times of activity and rest. “It’s important that all group members be ready to do the same thing at the same time,” Ronald Baenninger, who has studied yawning at Temple University in Philadelphia, says. Guardian/UK

[I must be really empathic; I yawned just reading the article about contagious yawning.]