A few come to mind: Mehrabian (1981), Fromkin and Rodman (1983), Barnum and Wolniansky (1989), Pease and Pease (2004). In regards to the face specifically take

A few come to mind: Mehrabian (1981), Fromkin and Rodman (1983), Barnum and Wolniansky (1989), Pease and Pease (2004). In regards to the face specifically take a look at Atkinson (2002), Garau, Slater and Bee (2001). The impact of Hand and Arm movement in regards to communication were studied by Mulken, Andre and Muller in 1998, and in 2002 by Craig, Gholson and Driscoll. Of course the study with the most impact is Mehrabian's 7-38-55 'rule' (which it isn't!). It's wildly misunderstood, but his study found in any communication scenario 7% of information received is through the words spoken, 38% is through the tone of voice, and 55% is though bodily movements. Regardless of the numbers, it just points out that just because someone 'says' something, people don't believe them unless their body language agrees. If their tone, posture, eye-contact, etc.. are saying something else, people invariably believe the non-verbal regardless of the words said. It's been a while, but IIRC, the other studies never find that low of an impact with spoken word, yet it never exceeds 50% either. Lastly, the definition of nonverbal communications can vary widely, but I like Henley's (77) (as a starting point) which lists a few areas "... body postures and movements, facial expressions, gestures, touching, eye contact, use of space, and so on". Hope you find some of that useful.