Why Do We Yawn When Someone Else Does?
Someone across the room yawns, and within seconds you feel your own jaw begin to stretch, even though you were not tired a minute ago. It happens with strangers, with pets, and sometimes just from reading a sentence about yawning. It is one of the strangest reflexes in the human body, and researchers still do not fully agree on why it exists.
Here is what is known about the yawn itself, what makes it catch, what the evidence on empathy really says, and how far the effect reaches into the animal world.
First, what is a yawn for?
The plain yawn, the one you do alone, is not fully understood either. A yawn lasts about six seconds on average, involves a wide stretch of the jaw and a deep intake of air, and begins before birth: ultrasound studies show fetuses yawning from around the end of the first trimester.
The idea that you yawn to take in more oxygen is a popular one, but experiments have not supported it; breathing extra oxygen or carbon dioxide does not change how often people yawn. A better-supported hypothesis is that yawning helps regulate brain temperature. A yawn brings in cooler air and increases blood flow around the head, and in a 2007 experiment by Andrew and Gordon Gallup, people who held a cold pack to the forehead caught far fewer yawns while watching others yawn (about 9 percent, against about 41 percent with a warm pack). It was a small study with confounds and the hypothesis is still debated, but it fits the temperature idea better than the oxygen one. Another view is that yawning marks a shift in alertness, which fits with how often people yawn when they are bored or just waking.
What makes yawning “contagious”
Contagious yawning is a separate phenomenon from the solitary yawn, and it was first studied systematically by the psychologist Robert Provine in the 1980s. Seeing someone yawn, hearing it, or even reading about yawning can trigger the reflex in an observer. In experiments, roughly half of adults or more yawn while watching a video of yawning people, with estimates varying by study.
The effect appears to depend on a person’s social attention. It begins to show up in children at around four or five years of age, and not in younger ones, which suggests it depends on a developing ability to attend to other people.
The empathy connection: promising, but mixed
A popular explanation says contagious yawning reflects empathy. Some studies found that people who score higher on empathy tests are more likely to catch yawns, and that contagion is weaker in some children on the autism spectrum. Brain imaging has shown that watching yawning engages regions involved in social processing.
The picture is less tidy than the headlines suggest. Several later studies failed to find a consistent link between empathy scores and how easily people catch yawns, and some found that other factors, such as age, alertness, and even the time of day, explain a lot of the variation. The fair summary is that social connection plays a role, but a simple “empathy meter” claim is not well supported.
Who catches yawns more easily
- People you are close to. Several studies found yawns spread more readily between family and friends than between strangers, which fits a social explanation.
- People who are tired or bored. Alertness level changes both how often you yawn on your own and how easily you catch one.
- Children under about four, who rarely catch yawns from others.
Boredom is worth noticing. Bored time seems to drag, which is related to the broader way we perceive the passing of time, discussed in why time feels like it speeds up as you get older.
Do animals catch yawns too?
Yes, and not only from their own species. Chimpanzees catch yawns from each other, and studies suggest contagion is stronger between familiar individuals. Dogs have been shown to yawn after seeing a human yawn, and in some studies more often when the person was their owner than when it was a stranger, which some researchers read as a sign of social attunement across species, although replication results have been mixed. Evidence in other animals, including some birds and fish, is thinner, and in some cases it is not clear that the behavior is the same thing.
Can you stop it?
Not reliably. Trying to suppress a yawn takes effort, and thinking about it makes it more likely, which is why reading this article may have made you yawn. A few things reduce your chance of yawning: breathing deeply through the nose, which may relate to cooling, and keeping yourself alert with movement or a cool drink. None of them is a guarantee.
When you yawn most
Yawning follows a daily rhythm. Studies of people’s natural yawning have found that it peaks shortly after waking and in the hour or so before bedtime, which matches the idea that it is tied to shifts in alertness. People also report yawning more when they are bored, when they are sitting still, and in the moments before something demanding, such as a performance or a test.
This is part of why contagious yawning is so easy to trigger in meetings and lectures: the setting already encourages it, and one person’s yawn becomes a prompt for everyone else.
How age changes it
Susceptibility to catching yawns tends to change over a lifetime. It appears around age four or five, as described above, is common through adulthood, and in some studies declines in older adults. Researchers have suggested several possible reasons, including changes in attention and in social engagement, though the evidence is still being sorted out.
Is it a social tool?
Some researchers argue that contagious yawning has a function in groups. One idea is that synchronized yawning helps coordinate the alertness of a group, so that its members shift state together, which could be useful for animals that live in packs or herds. It is an intriguing hypothesis, but it is not proven, and other researchers see contagion as a side effect of the brain’s general tendency to mirror what it observes.
A small experiment you can try
If you are curious about your own pattern, keep a simple log for a week. Each time you notice a yawn, note the time and whether you were tired, bored, or reacting to someone else’s. Most people find clear patterns within a few days: more yawns at predictable times, and a surprisingly large share that follow someone else’s. It makes a good way to see how much of the reflex is internal and how much is social.
When yawning is worth mentioning to a doctor
Ordinary yawning is not a medical concern. Occasionally, very frequent yawning that comes with persistent sleepiness, or that seems excessive and out of character, is worth raising with a doctor, since it can be linked to poor sleep, to certain medications, or to other conditions. That is rare, and in nearly all cases a yawn is just a yawn.
Quick answers
Does yawning mean I am tired?
Often, but not always. Yawning also happens when bored, before exercise, and during stress, and it may help signal a transition in alertness.
Why can’t I yawn on command?
You can fake the movement, but the reflex needs the right trigger. Many people produce a real one by thinking about yawning for a few seconds.
Is not catching yawns a problem?
No. Around half of people may not catch them in a given test, and it is not a medical indicator on its own.
The short version
- Solitary yawning is probably tied to brain temperature and alertness, not oxygen.
- Contagious yawning develops in early childhood and is stronger among people who know each other.
- The link to empathy is suggestive but inconsistent across studies.
- Dogs and chimpanzees also catch yawns, especially from familiar companions.
Sources
- Gallup, A. C., and Gallup, G. G. (2007). Yawning as a brain cooling mechanism: nasal breathing and forehead cooling diminish the incidence of contagious yawning. Evolutionary Psychology. Link
