Unpleasant words can affect the detection of morphosyntactic errors: An ERP study on individual differences

In recent years, several ERP studies have investigated whether the early computation of agreement is permeable to the emotional content of words. Some studies have reported interactive effects of grammaticality and emotionality in the left anterior negativity (LAN) component, while others have failed to replicate these results. Furthermore, novel findings suggest that grammatical processing can elicit different neural patterns across individuals. In this study, we aim to investigate whether the interaction between grammaticality and emotionality is restricted to participants with a specific neural profile. Sixty-one female native speakers of Spanish performed an agreement judgment task in noun phrases composed of a determiner, a noun, and an unpleasant or neutral adjective that could agree or disagree in gender with the preceding noun. Our results support the existence of two different brain profiles: negative and positive dominance (individuals showing either larger LAN or larger P600 amplitudes in ungrammatical stimuli than in grammatical ones, respectively). Interestingly, the neural pattern of these two groups diverged at different points along the time course. Thus, the negative dominance group showed grammaticality effects as early as 200 ms, along with parallel and autonomous processing of grammaticality and emotionality at the LAN/N400 time window. Instead, for the positive dominance group an early interaction was found at around 200 ms, evidencing a grammaticality effect that emerged only for unpleasant words. Our findings confirm the role of individual differences in the interplay between grammar and emotion at the neural level and call for the inclusion of this perspective in studies on syntactic processing.