Why Do We Yawn When Others Yawn?

Have you ever started yawning simply because someone else did? If so, congratulations: your brain is behaving exactly like millions of other brains around the world.

Contagious yawning is one of those strange human experiences that everyone recognizes but few people think about. One person yawns, another follows, and within seconds an entire room can look as though it collectively decided to take a nap.

The strange part is that scientists still do not fully agree on why it happens. What they do know is that contagious yawning appears to be linked to empathy, social connection and some surprisingly ancient wiring inside the human brain.

Yawning Is Older Than Humanity

Humans are not the only creatures that yawn.
Dogs yawn.
Cats yawn.
Chimpanzees yawn.
Even some fish and reptiles display yawning-like behaviors.

Scientists believe yawning evolved long before humans appeared. Whatever its original purpose was, it has survived hundreds of millions of years of evolution.

That alone suggests yawning does something useful. Exactly what remains a matter of debate.

Some older theories claimed yawning increases oxygen levels in the blood. Others suggested it helps wake up the brain. Neither explanation has received strong scientific support.

Today, many researchers believe yawning may help regulate brain temperature and shift the brain between different states of alertness. In other words, a yawn may function as a biological reset button.

Why Is Yawning Contagious?

This is where things become truly interesting. Ordinary yawning is common across many species. Contagious yawning is much rarer.

Humans can catch a yawn simply by:

• seeing someone yawn
• hearing someone yawn
• reading about yawning

In fact, there is a reasonable chance that this article has already made you yawn.

Sorry.

Researchers have found that contagious yawning appears to involve parts of the brain associated with social awareness and imitation.

Humans constantly copy one another in subtle ways.
We mirror facial expressions.
We imitate body language.
We unconsciously adopt accents.

Yawning may be part of the same social toolkit.

The Empathy Connection

One of the most fascinating discoveries is the apparent relationship between contagious yawning and empathy. Studies have repeatedly found that people are more likely to catch yawns from individuals they know well than from complete strangers.

Family members often trigger stronger responses than unfamiliar people.
Close friends frequently do as well. This has led some scientists to suggest that contagious yawning may reflect the brain’s tendency to synchronize with people it cares about.

The theory is not universally accepted, but it remains one of the most compelling explanations. Interestingly, contagious yawning has also been observed in chimpanzees, wolves and dogs, particularly among socially bonded individuals. Apparently, humans are not the only species that can catch social sleepiness.

What Happens Inside the Brain?

Scientists have used brain imaging techniques to examine what happens when people observe others yawning.

Several regions become active, including areas involved in:

• social cognition
• attention
• imitation
• emotional processing

One area that frequently appears in research is the mirror neuron system. Mirror neurons are brain cells that become active both when we perform an action and when we observe someone else performing it. These neurons may help explain why humans instinctively imitate behaviors without consciously deciding to do so.

Although researchers continue to debate the details, mirror neurons remain one of the leading explanations for contagious yawning.

Curious about what your brain does when it isn’t focused on anything in particular? Read our article What Happens in Your Brain When You Do Nothing?

Why Doesn’t Everyone Catch Yawns?

Here is another mystery.

Not everybody is equally susceptible. Some people catch yawns almost instantly.
Others seem completely immune. Age appears to play a role. Young children are generally less likely to experience contagious yawning than adults. Attention matters too. If people are distracted, the effect becomes weaker.

Scientists are still investigating whether personality traits, empathy levels and neurological differences influence how strongly someone responds. The answer is probably yes, but the exact relationship remains unclear. Which is science’s polite way of saying: “We’re working on it.”

A Shared Human Glitch

Contagious yawning is one of those behaviors that seems almost too trivial to study. Yet beneath its simplicity lies a fascinating question:

Why do human brains synchronize with one another at all?

Every day, people unconsciously copy gestures, expressions and emotions. Yawning may simply be one visible reminder that our brains are far less independent than we like to imagine.

The next time someone yawns and you immediately follow, don’t worry. You are not tired. Well, you might be. But you are also participating in one of humanity’s oldest and strangest forms of social communication.

Sources

Provine, R. R. (1989), Ethology: Yawning as a stereotyped action pattern and releasing stimulus

Platek, S. M., Critton, S. R., Myers, T. E., & Gallup, G. G. Jr. (Cognitive Brain Research 2003): Contagious yawning: the role of self-awareness and mental state attribution

Massen, J. J. M. & Gallup, A. C. (Neuroscience & Biobehavioral Reviews, 2017): Why contagious yawning does not (yet) equate to empathy

Romero, T., Konno, A., & Hasegawa, T. (PLoS ONE, 2013): Familiarity bias and physiological responses in contagious yawning by dogs support link to empathy