Behavioural and EEG evidence for inter-individual variability in late encoding stages of word production

Individuals differ in the time needed to name a picture. This contribution asks whether this inter-individual variability emerges in earlier stages of word production (e.g. lexical selection) or later stages (e.g. articulation) and examines the consequences of this variability for EEG group results. We measured participants’ (N = 45) naming latencies and continuous EEG in a picture-word interference task and naming latencies in a delayed naming task. Inter-individual variability in naming latencies in immediate naming (in contrast with inter-item variability) was not larger than the variability in the delayed task, suggesting that some variability in immediate naming originates in later stages of word production. EEG data complemented this interpretation: Differences between relatively fast vs. slow speakers emerged in response-aligned analyses in a time window close to the vocal response. We additionally present a method to assess the generalisability of the timing of effects across participants based on random sampling.