Abstract

Computer-mediated interaction poses new challenges for theories and models of social interaction concerned with relationships between humans and tools. This article discusses deaf signers using sign language in computer-mediated space, a case in which a new technological ‘tool’ is integrated into existing practices and conventions, but also requires new innovations. An influential model for studying humans, tool use, and social interaction is Activity Theory. However, in analyzing procedures deaf signers use in learning how to manage communication in computer-mediated space, key notions of Activity Theory, notably the ‘mediation’ properties of tools and the categories of subject and tool, are found to be insufficient. I propose adding to the concept of mediation and characterizing the relationship between subjects and new tools in interaction as one in which tools are ‘prostheses’ which interactants learn to inhabit. Based on looking at people learning to use a new technology, I argue, a key process in activities with new tools is a process where interactants learn how to enhance and constrain, extend and transform properties of the human body.