Perceptual Narrowing of Linguistic Sign Occurs in the 1st Year of Life

TLDR

Infants’ universal perception of language sounds narrows within the first year to native contrasts, a ubiquitous learning mechanism that supports language acquisition. The study examined whether perceptual narrowing also occurs for visual language by testing 40 infants with an eye‑tracking paradigm. The authors used an eye‑tracking paradigm to assess infants’ discrimination of ASL handshape contrasts. Four‑month‑old hearing infants could discriminate an ASL handshape distinction, but 14‑month‑old hearing infants could not, whereas 14‑month‑old ASL learners did discriminate, indicating that exposure to a visual language is required for maintenance of visual language discrimination.

Abstract

Over their 1st year of life, infants’“universal” perception of the sounds of language narrows to encompass only those contrasts made in their native language ( J. F. Werker & R. C. Tees, 1984 ). This research tested 40 infants in an eyetracking paradigm and showed that this pattern also holds for infants exposed to seen language—American Sign Language (ASL). Four‐month‐old, English‐only, hearing infants discriminated an ASL handshape distinction, while 14‐month‐old hearing infants did not. Fourteen‐month‐old ASL‐learning infants, however, did discriminate the handshape distinction, suggesting that, as in heard language, exposure to seen language is required for maintenance of visual language discrimination. Perceptual narrowing appears to be a ubiquitous learning mechanism that contributes to language acquisition.