Where body language is giving mixed signals (e.g. a smile that borders on a grimace or fails to involve the eyes) then the more negative, less socially desirable component is usually the more telling. This is because we are more often motivated to conceal unpleasant truths and anti-social feelings than pleasant, benign ones. Where there is a discrepancy between a particular hand gesture and the rest of the body (a posture), the posture will be the more telling.
