“The one most frequently associated with lying was a high intensity version of the so-called Duchenne smile involving both cheek/eye and mouth muscles. This is consistent with the “Duping Delight” theory that “when you’re fooling someone, you tend to take delight in it,” Sen explained.”
Why is he smiling when he says it?
“The one most frequently associated with lying was a high intensity version of the so-called Duchenne smile involving both cheek/eye and mouth muscles. This is consistent with the “Duping Delight” theory that “when you’re fooling someone, you tend to take delight in it,” Sen explained.”
https://www.rochester.edu/newscenter/data-science-facial-expressions-who-if-lying-321252/
This is an involuntary reaction and Trump isn’t meaning to smile, but he is lying and his facial expression gives him away.