Expectation enhances event-related responses to affective stimuli

How the expectation of forthcoming emotional events influences individuals' behaviors and brain responses to such events remains controversial. The present study addressed this issue using event-related potentials (ERPs) to overcome limitations in research techniques. In addition, a no cue condition was adopted as the unexpected condition to make the research paradigm closer to real life situations for ecological validity. Behavioral results showed that positive stimuli were experienced more pleasantly and negative ones were experienced more unpleasantly during the expected condition than the unexpected one. ERPs results also displayed larger P2, N2 and LPP amplitudes in the expected condition, regardless of stimulus valence. The finding that expected emotional events evoke enhanced behavioral and brain responses than the unexpected ones do provides a strong piece of evidence for the effect of expectation on emotion processing.