Even if you’ve gotten enough rest, if your nearby coworker yawns there’s a good chance you will, too.
If you often yawn when someone nearby is yawning, it may be because you feel a closer connection with the yawner. In 2015, researchers from Baylor University found (paywall) a link between an individual’s ability to feel empathy, and whether or not they would yawn after watching a video of someone else yawning. The more people felt connected with others, the more likely they were to yawn.
For the study, researchers recruited 135 college students, 57 of whom were men, and asked them to fill out a survey that measured their psychopathic traits (you can take it here). Individuals with psychopathy are more selfish, manipulative, and don’t feel empathy as well as other people. Then, the researchers showed participants short clips of people yawning, laughing, or having no facial expression at all. They found that participants who scored higher on a measure of coldheartedness—a measure of social and emotional intelligence—were less likely to yawn when they saw someone else do the same.
If you don’t yawn when someone nearby does, it doesn’t mean you’re a psychopath. You may just not know them well enough yet.
“The take-home lesson is not that if you yawn and someone else doesn’t, the other person is a psychopath,” Brian Rundle, a doctoral student in psychology and neuroscience at Baylor College and lead author of the study, said in a press release. “A lot of people didn’t yawn, and we know that we’re not very likely to yawn in response to a stranger we don’t have empathetic connections with.”
This research only illustrates a correlation between people who showed less empathy and failing to yawn; having one trait isn’t necessarily indicative of the other. But, it’s an interesting starting point for future research.