A nice article in the Sept. 2002 Social Psychology Quarterly documents an interesting fact: the presidential candidate who has the right tone of voice tends to win the election.
According to “communication accommodation theory,” low status people change their voices to accommodate high status people. The presidential candidate who more frequently changes the “F_0” range of his voice (which is a very low hum) during a debate signals that he is in the low-status position. The authors believe that voters respond strongly to this non-verbal, but strongly emotional, cue. The authors note that George W. Bush may have “won” the 2000 debate with Gore because he signaled his dominance in this fashion, although Gore was perceived by journalists to have won through superior rhetoric. The results of voice analysis correlate well with electoral outcomes and polls.