Activity Theory

A conceptual framework originating in Soviet psychology (Vygotsky, Leont'ev) and widely applied in HCI, which analyses human action as goal-directed activity mediated by tools, rules, community, and division of labour. Activity Theory provides a structured lens for studying how people interact with technologies — for example, examining how a developer (subject) uses an AI code assistant (tool) to accomplish a programming task (object). It is commonly used in qualitative accessibility research to organise observations across tool-mediated work.