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的时长上存在差异。本研究旨在探明该个体间变异产生于词汇产生的早期阶段（如词汇选择）还是后期阶段（如发音动作），并考察该变异对脑电图（EEG）组级分析结果的影响。我们通过图片-词语干扰任务采集了45名被试的命名反应时与连续脑电图数据，并在延迟命名任务中采集了被试的命名反应时。即时命名任务中命名反应时的个体间变异（与项目间变异相对）并未高于延迟命名任务中的变异水平，这表明即时命名的部分变异源于词汇产生的后期阶段。脑电图数据进一步佐证了这一解释：在接近发声反应的时间窗口内开展反应对齐分析时，可观察到快、慢命名者之间的脑电差异。此外，我们还提出了一种基于随机抽样的方法，用于评估效应出现时机在不同被试间的可推广性。