Mapping hand to world; Development of iconic representation in gesture and homesign

In both gesture and sign, objects and events can be represented by reproducing some of their features iconically. Iconic gestures do not typically appear until well into children’s second year of life, suggesting that the cognitive and/or communicative resources required are not trivial. Here we investigate how manual iconicity develops in two different communicative systems. Using longitudinal video corpora, we compare the emergence of manual iconicity in 52 hearing children learning a spoken language (co-speech gesture) to a deaf child creating a manual communication system (homesign). We focus on the shape of the hand, asking how handshape use changes between age 1 and 5, and how handshape choice relates to semantic content. We find broadly similar patterns of handshape development in co-speech gesture and homesign. This suggests that the cognitive building blocks underlying children’s ability to iconically map forms to meanings are shared across vastly different communicative systems.