My own typology research over the years revealed that strong eye contact during interaction is an Fi trait which corresponds to the Amygdala processes in the brain as an extension of the immaterial psyche. This contact has a psychic hold over how potentially influential Fi types or really any types are when engaged in assertive influential negotiations such as sales.

I think of an ESI I know perfectly well who explained to me that the bulk of her negotiating success in always getting whatever she wanted had to do with her study of body language eye contact and how to use it. She made a lot of money at an otherwise menial career path because of this skill she practiced at manipulating people for self-advantage. It is ironic we are called ethical types because I honestly find the behavior of many (but not all) ESIs highly unethical and scheming when taken too far.