Sentences in the Brain: Event-Related Potentials as Real-Time Reflections of Sentence Comprehension and Language Learning

From the perspective of a person trying to understand a sentence, language is a continuous flow of information distributed over time. Somehow, the listener translates this stream of information into discrete and rapidly sequenced units of sound, meaning, and structure, and does so in real time, that is, nearly instantaneously. The results of these complex analyses are then integrated into a single coherent interpretation, even in the presence of considerable ambiguity. The challenge facing us is to account for how people accomplish this. Asking the listener or reader for an answer to this question provides little useful information; the relevant processes are not generally available to conscious reflection. We must therefore rely on other methods of investigation. One might surmise that the ideal method would mirror the properties of comprehension itself (Osterhout, McLaughlin, & Bersick, 1997). The ideal method should provide continuous measurement throughout the process of understanding a sentence, have a temporal resolution exceeding that of the relevant processes, and be differentially sensitive to events occurring at different levels of analysis (phonological, syntactic, semantic, etc.). Furthermore, language comprehension is clearly a function of the human brain. Theoretical accounts of some of the most fundamental questions about human language (e.g., the ability of children to acquire language, and the effects of age on language-learning ability) rely explicitly on biological explanations. Compelling tests of these hypotheses necessarily require biological measurement. For these and other reasons, the ideal method should also provide a means for relating the obtained data to brain function.