Learning to look: The acquisition of eye gaze agreement during the production of ASL verbs

In American Sign Language (ASL), native signers use eye gaze to mark agreement (Thompson, Emmorey and Kluender, 2006). Such agreement is unique (it is articulated with the eyes) and complex (it occurs with only two out of three verb types, and marks verbal arguments according to a noun phrase accessibility hierarchy). In a language production experiment using head-mounted eye-tracking, we investigated the extent to which eye gaze agreement can be mastered by late second-language (L2) learners. The data showed that proficient late learners (with an average of 18.8 years signing experience) mastered a cross-linguistically prevalent pattern (NP-accessibility) within the eye gaze agreement system but ignored an idiosyncratic feature (marking agreement on only a subset of verbs). Proficient signers produced a grammar for eye gaze agreement that diverged from that of native signers but was nonetheless consistent with language universals. A second experiment examined the eye gaze patterns of novice signers with less than two years of ASL exposure and of English-speaking non-signers. The results provided further evidence that the pattern of acquisition found for proficient L2 learners is directly related to language learning, and does not stem from more general cognitive processes for eye gaze outside the realm of language.