Negative expectations influence behavioral and ERP responses in the subsequent recognition of expectancy-incongruent neutral events.

Previous studies have shown that expectancy incongruence in emotional stimuli influences the encoding (i.e., the first stage of memory processing) of the stimuli. However, it is unknown about whether expectancy incongruence influences later stages of memory processing, such as recognition. To this end, expectancy cues were presented prior to emotional pictures. Most often, the cues accurately indicated the emotional consequences of the pictures, but in some cases the consequence was incongruent with the expectations, and a picture from another emotional category was presented. Afterward, participants completed an unexpected recognition task in which old and novel pictures were not preceded by expectancy cues. The results showed that, in the encoding phase, expectancy incongruence reduced response accuracy when categorizing pictorial emotions, and the effect was smaller for neutral pictures than for negative pictures. ERP results showed stronger and weaker responses to expectancy incongruent pictures compared to congruent pictures in time ranges related to the encoding-related early and middle late positive potential (LPP), respectively. In the subsequent recognition phase, d' scores were higher for incongruent neutral pictures than for congruent ones. Expectancy incongruence enlarged the P2 response but reduced the recognition-related early LPP response for neutral pictures. However, effects of expectancy incongruence were not seen for negative pictures. Therefore, the findings in the present study indicate that negative expectations influence the later recognition of expectancy incongruent neutral events, whereas negative events are more resistant to the effects of expectation incongruence.