Semantic processing of adjectives and nouns in American Sign Language: effects of reference ambiguity and word order across development.

When processing spoken language sentences, listeners continuously make and revise predictions about the upcoming linguistic signal. In contrast, during comprehension of American Sign Language (ASL), signers must simultaneously attend to the unfolding linguistic signal and the surrounding scene via the visual modality. This may affect how signers activate potential lexical candidates and allocate visual attention as a sentence unfolds. To determine how signers resolve referential ambiguity during real-time comprehension of ASL adjectives and nouns, we presented deaf adults (n = 18, 19-61 years) and deaf children (n = 20, 4-8 years) with videos of ASL sentences in a visual world paradigm. Sentences had either an adjective-noun ("SEE YELLOW WHAT? FLOWER") or a noun-adjective ("SEE FLOWER WHICH? YELLOW") structure. The degree of ambiguity in the visual scene was manipulated at the adjective and noun levels (i.e., including one or more yellow items and one or more flowers in the visual array). We investigated effects of ambiguity and word order on target looking at early and late points in the sentence. Analysis revealed that adults and children made anticipatory looks to a target when it could be identified early in the sentence. Further, signers looked more to potential lexical candidates than to unrelated competitors in the early window, and more to matched than unrelated competitors in the late window. Children's gaze patterns largely aligned with those of adults with some divergence. Together, these findings suggest that signers allocate referential attention strategically based on the amount and type of ambiguity at different points in the sentence when processing adjectives and nouns in ASL.