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Why do psychopaths keep their heads still with a penetrating gaze? You might not realize, but we move our heads to convey different aspects of communication. A nod for agreement or a shake for dissent. Cocking the head to one side acts as a question.

When we couple head movements with facial expressions, we express even more. From conveying sympathy to indicating whose turn it is to speak next.

In other words, our heads give away a lot of personal information. This is exactly what the psychopath doesn’t want. A psychopath’s greatest tool is their devious nature and ability to manipulate. Keeping their head still is one way of hiding what they are thinking.

As for the penetrating gaze, studies have shown that psychopaths tend to hold a person’s gaze for longer than average. Throw in the fact that their pupils do not dilate when they are afraid, and you have one scary-looking dude. More...
https://www.learning-mind.com/psychopathic-stare-cues/

...usually when people see something upsetting, the pupil in the eye dilates (gets bigger) in response — a reflection of the body’s sympathetic nervous system (the ‘fight, flight, or freeze’ response) kicking into action.

But a 2018 studyTrusted Source of 82 males with interpersonal–affective psychopathic traits, a reduced pupil ‘response’ was noted when they were shown negative images. A different studyTrusted Source also found reduced pupil dilation among psychopaths when they listened to negative sounds, such as screaming.

Meanwhile, researchers have also found that those with psychopathic traits spend longer looking at images depicting emotions, such as pain and embarrassment.

“The subject of eyes and psychopaths are very interesting,” states Dr. Naomi Murphy, a consultant and forensic psychologist and founder of Octopus Psychology.
More...
https://psychcentral.com/health/identifying-psychopathic-stare#what-is-it

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When psychopaths fix their piercing eyes on someone they are talking to, their heads usually don’t move. A stationary head coupled with a lingering gaze is one of the main non-verbal signs of psychopathy.

But why do psychopaths do that? The reason is that when we move our heads during a conversation, it conveys our emotions. We nod in agreement, shake our heads in dissent, cock our heads when we are intrigued. Our eye movements also reveal our feelings and moods, like anger, disdain, boredom, and so on. We look away when we are appalled by something and look intently when something arouses our interest. This is what a true psychopath avoids

Read More Here... https://themindsjournal.com/psychopathic-stare-non-verbal-cues-psychopath/