Semantic priming in a first and second language: evidence from reaction time variability and event-related brain potentials

Abstract

We investigated individual differences in second language (L2) proficiency by looking at the efficiency or automaticity of semantic priming using behavioural and event-related brain potential (ERP) measures. In Experiment 1, 37 first language (L1) English speakers varying in second language (L2, French) proficiency made living/non-living judgments to English and French nouns in lists blocked by language. Sixty critical words were each presented twice, once primed by a semantic associate in the preceding trial (e.g. ADULT, CHILD) and once unprimed (e.g. RABBIT, CHILD). Measures of response time (RT) and intra-individual variability in response time (coefficient of variation, CV) were obtained. The CV provided an index of processing efficiency that has been related to automaticity. Participants performed faster and with lower CVs (i.e. with greater efficiency) in L1 than L2, and the more highly proficient bilinguals had lower CVs than the less proficient bilinguals. Experiment 2 replicated these results with 29 participants and provided an electrical brain activity measure of processing efficiency using the N400 ERP. The similar pattern of results obtained between the behavioural and N400 ERP CV measures supported the idea that the CV measure of electrical brain activity can provide useful information about the automaticity or efficiency of cognitive processing.