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

TL;DR

This study investigates inter-individual differences in word production timing, revealing that variability mainly arises in late stages of production, supported by behavioral and EEG data showing differences near vocal response.

Contribution

It demonstrates that inter-individual variability in naming latencies originates mainly in late stages of word production, using combined behavioral and EEG evidence.

Findings

Variability in naming latency is linked to late production stages.

EEG differences between fast and slow speakers occur near vocal response.

Group EEG results are influenced by individual differences.

Abstract

Individuals differ in the time it takes to produce words when naming a picture. However, it is unknown whether this inter-individual variability emerges in earlier stages of word production (e.g., lexical selection) or later stages (e.g., articulation). The current study measured participants' (N = 45) naming latencies and continuous EEG in a picture-word-interference task, as well as naming latencies in a delayed naming task. The inter-individual variability in naming latencies in immediate naming was not larger than the variability in the delayed task. Thus, a large part of the variability in immediate naming seems to originate in relatively late stages of word production. This interpretation was complemented by the EEG data: Differences between relatively fast vs. slow speakers were seen in response-aligned analyses in a time window close to the vocal response. Finally, we show that inter-individual variability can influence EEG results at the group level.