Understanding referential expressions in context: Use of common ground by children and adolescents with mental retardation

Listeners interpret utterances against the common ground, or network of pre suppositions shared with the speaker. The first purpose of the study was to determine whether individuals with mental retardation use the major source s of common ground (i.e., physical copresence, linguistic copresence, and c ommunity membership) to resolve referential ambiguity The second purpose wa s to determine whether they seek confirmation of their referent choices in accordance with the certainty of interpretation afforded by the common grou nd. The third purpose was to determine whether they signal noncomprehension when Faced with ambiguity and common ground that is not informative. The f inal purpose was to evaluate the relationship between within-group variabil ity in common ground use and measures of nonverbal cognition, receptive and expressive language, and social cognition. Participants were school-age in dividuals with mental retardation and typically developing children matched to them on nonverbal MA. Common ground use was examined in a role-playing task in which the participant responded to ambiguous utterances. Common gro und was manipulated within participants. We determined whether referent sel ections were appropriate For the common ground, whether they were accompani ed by confirmation requests, and whether noncomprehension was signaled. Bot h groups used all sources of common ground to resolve referential ambiguity at better than chance levels but were less successful in using community m embership. Both groups also requested confirmation of their referent choice s most often when the common ground was based on community membership. Both groups signaled noncomprehension when the common ground was not informativ e. Different aspects of common ground use were related to different predict ors for the group with mental retardation.