Why is Yawning Contagious?

Have you ever noticed yourself yawning after someone else yawns, even if you’re not tired? This past August, researchers at the University of Nottingham may have figured out why this phenomenon occurs, discovering that contagious yawning is triggered by an area of the brain that is responsible for motor function: the left primary motor cortex.

Reflexive yawning is considered a form of echopraxia, the automatic imitation of another person’s actions. While previous studies have shown that this form of yawning occurs in humans, chimpanzees, and dogs, this is one of the first studies to link contagious yawning and neural activity.

As part of the study, the researchers directed four separate groups of people to watch clips of individuals yawning. Different groups were instructed to either resist yawning or let yawning occur naturally, and participants in booth groups were hooked up to an electric stimulator—in true Frankenstein style—that shocked the brain’s left primary motor cortex.

The data revealed that attempts to resist yawning actually increase the urge to yawn, and that people have a natural tendency to yawn that is not affected by instructions. Most importantly, however, the researchers found that electrically stimulating the left primary motor cortex increased the likelihood of yawning, revealing that this area of the brain may play an important role in contagious yawning.