Dr. Paul Ekman has spend most of his life studying 'micro-expressions', which we cannot help but make, even when trying to hide our true feelings. These expressions flicker across our face for the briefest split-second, but we cannot control them.
Find his website here: Paul Ekman
The American T.V show 'Lie To Me' is based on his research, and explains it well, while at the same time being a gret show in itself.
Follow the link: Lie To Me