Fixed-effects estimates: Response time.

We investigated early electrophysiological responses to spoken English words embedded in neutral sentence frames, using a lexical decision paradigm. As words unfold in time, similar-sounding lexical items compete for recognition within 200 milliseconds after word onset. A small number of studies have previously investigated event-related potentials in this time window in English and French, with results differing in direction of effects as well as component scalp distribution. Investigations of spoken-word recognition in Swedish have reported an early left-frontally distributed event-related potential that increases in amplitude as a function of the probability of a successful lexical match as the word unfolds. Results from the present study indicate that the same process may occur in English: we propose that increased certainty of a ‘word’ response in a lexical decision task is reflected in the amplitude of an early left-anterior brain potential beginning around 150 milliseconds after word onset. This in turn is proposed to be connected to the probabilistically driven activation of possible upcoming word forms.