A revisit to interactions of stimulus quality and semantic context on N400 in visual word recognition.

Much behavioral research has revealed interactive effects between stimulus quality and semantic priming in visual word recognition, practically in favor of the interactive activation model. However, the limited number of event-related brain potential (ERP) studies have yielded inconsistent results considering this interaction's impact on N400 amplitude. The current ERP study aimed to examine whether the joint effects of stimulus quality and semantic priming were specific to the lexical decision task. We used both behavioral measures and ERP recordings to evaluate the joint effects of stimulus degradation (i.e. highly vs. slightly degraded) and semantic priming (i.e. semantically related vs. unrelated) in a lexical decision task involving visual recognition of Chinese characters. The results showed significant degradation-by-priming interactions on response times and N400 amplitude ( P  < 0.05), with larger semantic priming effects on slightly degraded targets. These converging behavioral and electrophysiological findings provide evidence in accordance with the interactive activation models of visual word recognition, in which the early-stage visual processing (i.e. degradation) cascades into the later-stage semantic processing (i.e. priming), thus yielding interactions observed in N400 amplitude.