Think you could spot a psychopath? They often blend into the background, so chances are you probably can’t.
The study, published in the journal Personality Disorders: Theory, Research, and Treatment, involved 82 male mentally disordered offenders. The researchers examined how their pupils reacted to visual images of real-world scenes, auditory sound clips, and videos of dynamic facial expressions. Some of the pictures were nice, like puppies, and some were negative, such as bloody injuries.