According to a new study, people with psychopathic traits are less likely to catch a yawn from the sleepy people around them because they tend to lack empathy and emotional connections with others.
It has long been believed that “contagious yawning” is actually a deep-seated signal that demonstrates an empathetic connection with another person. People with strong emotional ties, such as family members, share yawns more easily than they do with strangers. And it’s not unique to humans – contagious yawning has been documented in many species of socially-inclined mammals, including chimpanzees, wolves and dogs.
"I thought, 'If it's true that yawning is related to empathy, I'll bet that psychopaths yawn a lot less.' So I put it to the test," Brian Rundle, the study’s lead author and a doctoral student in psychology and neuroscience at Baylor University said in a statement.
If someone with a strong empathetic nature “catches” a yawn easily, it stands to reason that a person who lacks empathy would not yawn as often. To see if this was true, Rundle first had the study’s participants answer a standard psychological test to figure out where they landed on the psychopathic spectrum. Then, they were sat in a darkened room and given noise-cancelling headphones to wear while short video clips of yawns, smiles and blank faces played on a screen. Electrodes on the participants’ faces recorded the number and frequency of their yawns alongside physiological responses, like muscle movement and nerve reactions. The study found that the less empathy a person demonstrated on the test, the less frequent they were to yawn in response to the videos.
But while Rundle’s results imply a correlation between psychopathy and how frequently someone catches a yawn, it doesn’t mean that not yawning is a definite sign that someone has psychopathic tendencies.
"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,” Rundle said. “This is a good starting point to ask more questions.”