Here’s a simple personality test to try on whoever is sitting opposite you as you read this column. When you’re fairly sure that he or she is looking at you – but without checking too obviously – yawn. Does the other person follow suit?
If they do, it suggests that your companion is a fairly empathic person (or at least has a fair amount of empathy for you). A growing body of evidence suggests that contagious yawning is closely linked to empathy. For starters, babies don’t catch yawns. Yawn contagion only starts to appear around the age of four or five, about the same time as empathy.
Secondly, people with psychopathic personality traits, and people with autism – a condition associated with lower levels of empathy – are also less likely to catch yawns.