Casasanto1 and Jasmin do an interesting study that shows a link between action and emotion, positive messages are more strongly associated with dominant hand gestures and negative messages with non-dominant hand gestures.
We analyzed speech and gesture (3012 spoken clauses, 1747 gestures) from the final debates of the 2004 and 2008 US presidential elections, which involved two right-handers (Kerry, Bush) and two left-handers (Obama, McCain). Blind, independent coding of speech and gesture allowed objective hypothesis testing. Right- and left-handed candidates showed contrasting associations between gesture and speech. In both of the left-handed candidates, left-hand gestures were associated more strongly with positive-valence clauses and right-hand gestures with negative-valence clauses; the opposite pattern was found in both right-handed candidates...The results suggest that the hand speakers use to gesture may have unexpected (and probably unintended) communicative value, providing the listener with a subtle index of how the speaker feels about the content of the co-occurring speech.