LAUSR

Differences in caregiver input across socioeconomic status (SES) predict syntactic development, but the mechanisms are not well understood. Input effects may reflect the exposure needed to acquire syntactic representations during learning (e.g., does the child have the relevant structures for passive sentences?) or access this knowledge during communication (e.g., can she use the past participle to infer the meaning of passives?). Using an eye-tracking and act-out paradigm, the current study distinguishes these mechanisms by comparing the interpretation of actives and passives in 3- to 7-year-olds (n=129) from varying SES backgrounds. During the presentation of spoken sentences, fixations revealed robust disambiguation of constructions by children from higher-SES backgrounds, but less sensitivity by lower-SES counterparts. After sentence presentation, decreased sensitivity generated interpretive challenges and average SES-related differences for passives requiring syntactic revision ("The seal is quickly eaten by it"). Critically, no differences were found when revision was not needed ("It is quickly eaten by the seal"). These results suggest that all children shared an ability to acquire passives, but SES-related differences in real-time processing can impact the accuracy of utterance interpretation.