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’ (<i>N </i>= 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.

个体在图片命名所需时长上存在显著差异。本项研究旨在探究该个体间变异源于词汇产生的早期阶段（如词汇选择）还是晚期阶段（如发音），并考察该变异对脑电（Electroencephalogram, EEG）组级分析结果的影响。本研究通过图片-词语干扰任务，采集了45名被试的命名反应时与连续脑电信号，并借助延迟命名任务测量了其命名反应时。即时命名任务中的个体间反应时变异（区别于项目间变异）并未显著大于延迟命名任务中的变异，这提示即时命名的部分变异源于词汇产生的晚期阶段。脑电数据进一步佐证了这一推论：在接近发声反应的时间窗口内开展反应对齐分析时，可观测到快、慢命名者之间的脑电差异。此外，本研究还提出了一种基于随机抽样的方法，用于评估效应时序在不同被试间的可推广性。