Natural speech processing: An analysis using event-related brain potentials

Abstract

In two experiments, event-related brain potentials were collected as subjects listened to spoken sentences. In the first, all words were presented as connected (natural) speech. In the second, there was a 750-msec interstimulus interval (ISI) separating each of the words. Three types of senten-ending words were used: best completions (contextually meaningful), unrelated anomalies (contextually meaningless), and related anomalies (contextually meaningless but related to the best completion). In both experiments, large N400s were found for the unrelated and related anomalies, relative to those found for the best-completion final words, although the effect was earlier and more prolonged for unrelated anomalies. The auditory N400 effect onset earlier in the natural-speech experiment than it did in either the 750-msec ISI experiment or previous visual studies.