The fact that people yawn when they see someone else yawning has been related to empathy levels is some studies, while others disagree. However, a research conducted on college students finds that people who have psychopathic traits – especially lack of empathy – are less affected by other people’s yawns.
An article published on mental_floss reports that some researchers from Baylor University in Texas tried to make 135 students react to someone’s yawning with another yawn, and they also made them complete questionnaires regarding personality traits, which measure psychopathic characteristics such as selfishness, impulsivity, lack of empathy, or a tendency to manipulate. After this, they were asked to sit in front of a computer and watch a 10-second video of facial movements, including yawning, while electrodes were attached to their faces under the lower eyelids, on their foreheads, on the outer corners of their eyes, and on their fingertips, in order to measure movement in reaction to the video.
The results were that the higher the students rated on measures of cold-heartedness, the less likely they were to yawn when seeing someone yawn.
However, it is true that people tend to empathize more with someone they actually know rather than a stranger in a video, and the sample size was also pretty small. Still, according to one of the authors of the study, “what we found tells us there is a neurological connection – some overlap – between psychopathy and contagious yawning.”