Paul Ekman is a psychologist who's gotten a lot of attention lately for his studies of facial expressions. It's a hot issue now because of face recognition software which not only spots terrorists but is used increasingly as a kind of lie detector.
According to Ekman the long lasting expressions can be faked a lot easier than the short-lived ones which may only last for half a second. The short ones are almost involuntary and are fairly sure indicators of what the person's really thinking.
See if you agree with Ekman about how to interpret the short-lived expressions below.
Face #1 (above): Neutral mouth and drooping eyes indicate a slight sadness or tiredness. The eyes still have focus so the tiredness is mild. 
Face#2 (above): If you guessed anger Ekman says you'd be wrong. This is disgust. You can tell by the wrinkled nose and narrowed eyes.
Face #3 (above): Anger or pointed sadness, but this time expressed with the lowered lips alone. Compare this to #1 where the anger is expressed with the eyes alone.
Face #4 (above): Slight enjoyment expressed with the lips alone. The eyes are neutral.
face#5 (above): Highly controlled anger. The woman's getting mad and may not be aware of it herself yet. If you see this face on a real person it means trouble is brewing.
Face #6 (above): Disgust, this time expressed with a slightly raised upper lip and not the nose and eyes as in #2.
Face #7 (above): Upset, miserable. The lowered brows and tensed lower eyelids signal anger as well.
Face#8 (above): Masked anger. Covering up anger with a happy smile. In some circumstances could be amusement at being perplexed.
I'm not recommending the book, I've only had time to skim it, but I thought you'd like to know about it. There's not really enough pictures. How can you discuss faces in a book that's mostly text?
