Also, if there are people who gesture's give away too much they may try to restrain themselves as gesture verges on an involuntary action. Gesture's cousin and sister to involuntary actions. We rely on expressions a great deal, but we rarely think of them. A smile, a frown, a snarl can say a great deal. Some may be deliberate, some may not be.
Humans are very facially-oriented.
Indeed, one of my hobbies is learning to draw, and I started with the human face. All rights reserved. No part of this may be reproduced or reprinted without permission in writing from the author.