Abstract
The objective of this article was to review existing research to assess the evidence for predictive processing in sign language, the conditions under which it occurs, and the effects of language mastery on the neural bases of PP. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework. We searched peer-reviewed electronic databases and gray literature. We also searched the reference lists of records selected for the review and forward citations to identify all relevant publications. We searched for records based on five criteria. To reduce the risk of bias, the remaining two authors with expertise in sign language processing and a variety of research methods reviewed the results. Disagreements were resolved through extensive discussion. In the final review, 7 records were included, of which 5 were published articles and 2 were dissertations. The reviewed records provide evidence for PP in signing populations, although the underlying mechanism in the visual modality is not clear. The reviewed studies addressed the motor simulation proposals, neural basis of PP, as well as the development of PP. All studies used dynamic sign stimuli. Most of the studies focused on semantic prediction. The question of the mechanism for the interaction between one’s sign language competence and PP in the manual-visual modality remains unclear, primarily due to the scarcity of participants with varying degrees of language dominance. There is a paucity of evidence for PP in sign languages, especially for frequency-based, phonetic, and syntactic prediction. However, studies published to date indicate that Deaf native/native-like L1 signers predict linguistic information during sign language processing, suggesting that PP is an amodal property of language processing.Systematic Review Registration[https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021238911], identifier [CRD42021238911].