Tools for language: patterned iconicity in sign language nouns and verbs

When naming certain hand-held, man-made tools, American Sign Language (ASL) signers exhibit either of two iconic strategies: a handling strategy, where the hands show holding or grasping an imagined object in action, or an instrument strategy, where the hands represent the shape or a dimension of the object in a typical action. The same strategies are also observed in the gestures of hearing nonsigners identifying pictures of the same set of tools. In this paper, we compare spontaneously created gestures from hearing nonsigning participants to commonly used lexical signs in ASL. Signers and gesturers were asked to respond to pictures of tools and to video vignettes of actions involving the same tools. Nonsigning gesturers overwhelmingly prefer the handling strategy for both the Picture and Video conditions. Nevertheless, they use more instrument forms when identifying tools in pictures, and more handling forms when identifying actions with tools. We found that ASL signers generally favor the instrument strategy when naming tools, but when describing tools being used by an actor, they are significantly more likely to use more handling forms. The finding that both gesturers and signers are more likely to alternate strategies when the stimuli are pictures or video suggests a common cognitive basis for differentiating objects from actions. Furthermore, the presence of a systematic handling/instrument iconic pattern in a sign language demonstrates that a conventionalized sign language exploits the distinction for grammatical purpose, to distinguish nouns and verbs related to tool use.