Why would computer scientists want to study the facial expression and gesture?

Computer scientists might be interested in natural communications as a test bed for exercising computational techniques or theories. For example, a researcher might be interested in modelling a communications system used by a particular species. Alternatively, the interest might be in devising an artificial set of signs that can be readily recognized by a computer. Such a system might be analogous to the use of symbolic 'gestures' on a personal digital assistant, instead of an engine that recognizes natural, cursive handwriting. Nonverbal human communication is a challenging system, and many other issues are raised in the NSF Understanding the Face report.

In behavioral science, researchers are interested in analyzing natural systems of nonverbal communication.