The syntactic and semantic processing of mass and count nouns: an ERP study

Abstract

The present study addressed the question of whether count and mass nouns are differentially processed in the brain. In two different ERP (Event-Related Potentials) tasks we explored the semantic and syntactic levels of such distinction. Mass and count nouns typically differ in concreteness, hence the effect of this important variable was factorially examined in each task. Thus the stimuli presented were: count concrete, count abstract, mass concrete or mass abstract. The first experiment (concrete/abstract semantic judgment task) involved the interaction between the N400 concreteness effect and the Mass/Count condition, revealing a substantial effect between mass and count nouns at the semantic level. The second experiment (sentence syntactic violation task) showed a Mass/Count distinction on left anterior negativity (LAN) and on P600 components, confirming the difference at the syntactic level. This study suggests that the brain differentiates between count and mass nouns not only at the syntactic level but also at the semantic level. Implications for our understanding of the brain mechanisms underlying the Mass/Count distinction are discussed.

Figure 1. Overlap of the grand average ERPs in the semantic task for concrete count and mass nouns recorded from nine selected scalp sites.

As observed in Figure 2a, the brain waves in the mass condition diverge from those in the count condition as early as about 250 ms and particularly in the left parietal site (P3 electrode).

Figure 2. Overlap of the grand average ERPs in the semantic task for abstract count and mass nouns recorded from nine selected scalp sites.

Figure 3. Grand average ERPs recorded in the morphosyntactic task for concrete count and mass nouns recorded from six selected scalp sites.

Recordings from well-formed sentences are presented in the left panel and from ill-formed sentences in the right panel.

Figure 4. Grand average ERPs recorded in the morphosyntactic task at midline electrodes.

In the left column ERPs are compared between (a) well- and ill-formed sentences and (b) between concrete and abstract nouns in the right column.

Figure 5. Grand average ERPs recorded in the semantic task at midline electrodes (Fz  =  Frontal; Cz  =  Central, Pz  =  Parietal).

In the left column ERPs are compared between (a) concrete and abstract conditions; the brain waves in the abstract condition diverge from those in the concrete condition as early as about 225 ms; (b) mass and count nouns in the right column. In this and subsequent figures, amplitude (µV) is represented on the ordinate, with negative voltage up, and time (ms) on the abscissa.

Figure 6. Grand average ERPs recorded in the morphosyntactic task for abstract count and mass nouns recorded from six selected scalp sites.

Recordings from well-formed sentences are presented in the left panel and from ill-formed sentences in the right panel.

Figure 7. Design scores from PLS analysis for the two tasks (semantic and morphosyntactic).

CA: Count Abstract, CC: Count Concrete, MA: Mass Abstract, MC: Mass Concrete, SEM: Semantic Task, MORPH: Morphosyntactic Task. Note that for Morphosyntactic tasks only well-formed sentences were used.

Figure 8. Electrode saliencies relative to the first latent variable of PLS analysis for all recorded electrode sites.

Black circles represent the time points with stable effect (p < .01).

Figure 9. Sequence of events within a trial of each task.