Event-related potential correlates of the expectancy violation effect during emotional prosody processing

The present study investigated the expectancy violation effects evoked by deviation in sentential emotional prosody (EP), and their association with the deviation patterns. Event-related potentials (ERPs) were recorded for mismatching EPs with different patterns of deviation and for matching control EPs while subjects performed emotional congruousness judgment in Experiment 1 and visual probe detection tasks in Experiment 2. In the control experiment, EPs and acoustically matched non-emotional materials were presented and ERPs were recorded while participants judged the sound intensity congruousness. It was found that an early negativity, whose peak latency varied with deviation pattern, was elicited by mismatching EPs relative to matching ones, irrespective of task-relevance. A late positivity was specifically induced by mismatching EPs, and was modulated by both deviation pattern and task-relevance. Moreover, these effects cannot be simply attributed to the change in non-emotional acoustic properties. These findings suggest that the brain detects the EP deviation rapidly, and then integrates it with context for comprehension, during which the emotionality plays a role of speeding up the perception and enhancing vigilance.