How the mass counts: an electrophysiological approach to the processing of lexical features.

Nouns may refer to countable objects such as tables, or to mass entities such as rice. The mass/count distinction has been discussed in terms of both semantic and syntactic features encoded in the mental lexicon. Here we show that event-related potentials (ERPs) can reflect the processing of such lexical features, even in the absence of any feature-related violations. We demonstrate that count (vs mass) nouns elicit a frontal negativity which is independent of the N400 marker for conceptual-semantic processing, but resembles anterior negativities related to grammatical processing. This finding suggests that the brain differentiates between count and mass nouns primarily on a syntactic basis.