Proceedings of the Annual Meeting of the Cognitive Science Society

We investigate the development of children’s early grammat-ical knowledge using the test case of the English regular plu-ral. Previous research points to early generalization, with chil-dren applying an abstract morphological rule to produce novelplurals well before 24 months. At the same time, childrenuse the plural inconsistently with familiar object words, anddemonstrate limited receptive knowledge of the plural in theabsence of supporting linguistic features. In the first studyto test knowledge of the plural within participants using aparadigm matched across comprehension and production, weconduct two experiments with n = 52 24-36-month-olds: aneyetracking task to evaluate what they understand, and a sto-rybook task to test how they use the plural. We manipulateboth novelty (novel vs. familiar object words) and phonolog-ical form (/s/ vs. /z/ plurals). We find strong, age-related ev-idence of productive knowledge of the plural in an expressivetask, but do not find evidence of receptive knowledge in thesesame children.