Contextual influences of emotional speech prosody on face processing: how much is enough?

The influence of emotional prosody on the evaluation of emotional facial expressions was investigated in an event-related brain potential (ERP) study using a priming paradigm, the facial affective decision task. Emotional prosodic fragments of short (200-msec) and medium (400-msec) duration were presented as primes, followed by an emotionally related or unrelated facial expression (or facial grimace, which does not resemble an emotion). Participants judged whether or not the facial expression represented an emotion. ERP results revealed an N400-like differentiation for emotionally related prime-target pairs when compared with unrelated prime-target pairs. Faces preceded by prosodic primes of medium length led to a normal priming effect (larger negativity for unrelated than for related prime-target pairs), but the reverse ERP pattern (larger negativity for related than for unrelated prime-target pairs) was observed for faces preceded by short prosodic primes. These results demonstrate that brief exposure to prosodic cues can establish a meaningful emotional context that influences related facial processing; however, this context does not always lead to a processing advantage when prosodic information is very short in duration.