Translations:Adventist Youth Honors Answer Book/Outreach/Christian Grooming & Manners (North American Division)/41/en
From Pathfinder Wiki
People can adopt a facial expression as a voluntary action. However, because expressions are closely tied to emotion, they are more often involuntary. It can be nearly impossible to avoid expressions for certain emotions, even when it would be strongly desirable to do so; a person who is trying to avoid insult to an individual he or she finds highly unattractive might nevertheless show a brief expression of disgust before being able to resume a neutral expression. The close link between emotion and expression can also work in the other direction; it has been observed that voluntarily assuming an expression can actually cause the associated emotion.
