Electrophysiological correlates of incidental L2 word learning from dialogue

We aimed to determine the electrophysiological correlates of incidental L2 word learning during dialogue, bridging memory and second language acquisition research in a realistic, but strictly controlled experimental paradigm. Native Dutch speakers of L2 English learned English words previously unknown to them (as confirmed in a ‘hidden’ pretest) through auditory input in a dialogue-like setting revolving around price comparisons, while we measured their EEG. Hearing an unknown as compared to a known word elicited an early and sustained negativity, as well as a later LPC that was actually predictive of subsequent learning success. Notably, in a second block, we found that ERPs to novel words that had just been learned in the previous block were already undistinguishable from those for known words, while not yet learned novel words still showed similar ERP signatures as in block 1. This lends support for a fast learning mechanism in adults incidentally ‘picking up’ new L2 words.