The "Cheek Scratch with an Open Mouth," is a very common expression of disagreement-related anxiety. It is particularly common among men. Here Hugh Grant demonstrates this nonverbal cue nicely. Of course, Mr. Grant is an accomplished actor - but still very human. Although he many be able to control his body language better than most - his emotions are still revealed when he's in an anxiety producing scenario. Often seen in conjunction with this gesture (but not in this image) are an elevation of the eyebrows and forehead. Hugh's eyebrows are in a normal position, but if they had been elevated and his entire forehead (not just the central portion) wrinkled (muscles contracted) there would be an additional emotional component of apprehensiveness-doubt. When you see these signals simultaneously or within a few seconds, it constitutes a "Gesture Cluster". It's a signal that a person is in disagreement with what they are seeing and/or hearing and believe a different course of action should be taken. In this context they usually have a specific plan in mind. Be aware that they also may not be so revealing of their thoughts with their words - for this gesture often accompanies clandestine tactics. It is very commonly seen in business meetings or negotiations - and thus is a fantastic tell.