Lexical access versus lexical decision processes for auditory, visual, and audiovisual items: Insights from behavioral and neural measures

In two experiments, we investigated the relationship between lexical access processes, and processes that are specifically related to making lexical decisions. In Experiment 1, participants performed a standard lexical decision task in which they had to respond as quickly and as accurately as possible to visual (written), auditory (spoken) and audiovisual (written + spoken) items. In Experiment 2, a different group of participants performed the same task but were required to make responses after a delay. Linear mixed effect models on reaction times and single trial Event-Related Potentials (ERPs) revealed that ERP lexicality effects started earlier in the visual than auditory modality, and that effects were driven by the written input in the audiovisual modality. More negative ERP amplitudes predicted slower reaction times in all modalities in both experiments. However, these predictive amplitudes were mainly observed within the window of the lexicality effect in Experiment 1 (the speeded task), and shifted to post-response-probe time windows in Experiment 2 (the delayed task). The lexicality effects lasted longer in Experiment 1 than in Experiment 2, and in the delayed task, we additionally observed a “re-instantiation” of the lexicality effect related to the delayed response. Delaying the response in an otherwise identical lexical decision task thus allowed us to separate lexical access processes from processes specific to lexical decision.