Psychopaths have limited head movement in conversation studies indicate. But why?
I would propose because they are absolutely shit at reading fascial expressions and body language in general, thus don't mimic it themselves. This is caused by a total lack of empathy.
This suggest head movement are signals for others we interact with, rather than instinctive, unconscious bodily movements. Head movements are a response to socialising.
Psychopaths act emotions. They overact, but their heart is not in it. You can see it in their eyes. You want examples of this overacting?
Donald Trump. Hillary Clinton. Nancy Pelosi. Joe Biden also, but not so animated, just smiles. Tom Cruise. Netanyahu does not pretend what he is, no acting at all.
What all these people lack is empathy. They direct that outward reaching feeling back towards themselves instead.
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