Distinct Neural Responses to Social and Semantic Violations: An N400 Study

We investigated event-related brain potential correlates of encountering context-incongruent social information. Building on evidence that information semantically incongruent with its context elicits an N400 response (a prominent negative-going deflection in the ongoing electroencephalogram; EEG), we hypothesized that statements incongruent (relative to congruent) with basic standards of amicable treatment by others (e.g., "Your friend breaks your computer and then laughs [apologizes]") would elicit larger-amplitude N400 responses. EEG was recorded from N = 20 undergraduates while they viewed 106 semantic-dimension and 106 social-dimension sentences. We obtained the classic N400 effect to semantic violations, but we did not observe greater N400 amplitudes to incongruent than to congruent social-dimension sentences. Our findings of N400 modulation by semantic violations but not social norm violations help clarify potential boundary conditions for eliciting the N400.