What can we tell from the face? There're mixed data, but some show a pretty strong coherence between what is felt and what’s expressed on the face. Happiness, sadness, disgust, contempt, fear, anger, all have prototypic or characteristic facial expressions. In addition to that, you can tell whether two emotions are blended together. You can tell the difference between surprise and happiness, and surprise and anger, or surprise and sadness. You can also tell the strength of an emotion. There seems to be a relationship between the strength of the emotion and the strength of the contraction of the associated facial muscles.
LAWRENCE IAN REED is a Visiting Assistant Professor of Psychology, Skidmore College. Lawrence Ian Reed's Edge Bio page