Speed limits and red flags: why number agreement accidents happen

Abstract

Trouble in language production sometimes surfaces in errors and sometimes surfaces in delays. Since these two symptoms of difficulty can trade off, theories may make predictions that are confirmed with measures of accuracy but disconfirmed with measures of speed, and vice-versa. In work on grammatical agreement in particular, there are accounts of variability in verb number production that emphasize the roles of lexical sources of number information and accounts that emphasize structural sources. Depending on whether speed or accuracy is measured these alternative views can differ in the success of their predictions. To evaluate the alternatives, we carried out six experiments gauging speed and accuracy together in producing agreement. The data were analyzed using a statistical method that integrates speed and accuracy into a coherent framework. The findings demonstrate that grammatical agreement mechanisms are substantially more sensitive to conceptual than to lexical forces, confirming a central hypothesis of a structural account of sentence production