Behavioral studies have shown that in healthy humans, the left side of the face is emotionally more expressive than the right (Sackeim et al 1978). Additionally, processing of positive emotions is potentiated when emotional stimuli are presented to the left hemisphere (via the right ear or the right visual field), and negative emotions are potentiated when presented to the right hemisphere (Davidson et al 1987; Burton and Levy 1989). Emotional intonation (prosody) is more easily recognized when presented to the left ear (Erhan et al 1998), and stimuli presented in the left visual field are judged as more emotional (Levine and Levy 1986) and elicit greater autonomic responses (Spence et al 1996).
