Yawning is contagious. That is something that used to be considered merely anecdotal knowledge. We all knew it happened, even though not every time, and science only had to formalize it with a few proper studies. What was once common knowledge has become scientific knowledge through systematic, replicable experiments. Science has done more than formalize what we’ve always known, though. It has put solid numbers to the phenomenon. Between forty- and sixty-percent of people who witness yawning or hear it talked about will end up yawning themselves. Are you yawning now?
Empathetic people are more likely to catch the yawns. People less able to sense other people’s feelings, or less able to imagine them, are less susceptible to contagious yawning. Schizophrenics, who have great difficulty identifying with other people’s state of mind, almost never catch them. One hypothesis for contagious yawning is that it helps to coordinate group activity, or is a symptom of our need to identify with the group.
The physiological cause for yawning is still not clear, but there appears to be a strong correlation with those times when we’re struggling against sleep. We do most of our yawning early in the morning and late in the evening. It’s also prevalent in classrooms, churches, meetings and while listening to speeches. Those are all places where the infectiousness of yawning can be readily observed.
For a while it was thought that sympathetic yawning might be associated with the mirror-neuron system in the brain. That is the brain circuitry that is active both when we do something ourselves, and when we are aware of someone else doing the same thing. For instance, the same neurons are activated whether one plays a tune on the piano or listens to someone else play the same tune. Studies have shown that the mirror-neuron system is not involved in contagious yawning. That’s because we catch the yawns subconsciously, while the mimicry of mirroring is more of a conscious activity.
Brain scans have shown something, but so far it’s not what would be expected. There is a region of the brain which is associated with our unconscious analysis of the emotions in facial expressions. The paradox is that the region is deactivated rather than activated during contagious yawning. It’s not clear why, yet.
Yawning is contagious. It’s even possible to make your dog catch it. They want to belong, too.