Alright let’s just hear this one out shall we.
Have you ever slyly wondered if one of your mates or colleagues is a psychopath? They seem to be a little meaner than necessary and they hate
The Notebook and kittens.
Well according to research by
Personality and Individual Differences you can tell if a person has sadistic or narcissistic tendencies based on how they yawn – specifically if they do or do not yawn at all.
According to the study, psychopathy is characterized by a general antisocial lifestyle with behaviors including being selfish, manipulative, impulsive, fearless, callous, possibly domineering, and particularly lacking in empathy.

Yawning is contagious and linked very closely to empathy. The study observed over 135 students and noted whether they responded to a yawn or not. They discovered that those who don’t yawn lacked empathy and were more selfish and disconnected emotionally than others.
It further noted that those who don't find yawning contagious are four times more likely to identify with some psychopathic tendencies.
So there you have it if you want to figure out if someone is a psychopath or not, simply yawn in their presence.