When users of interactive computers must work with new software without formal training , they rely on strategies for ''exploratory learning'' . These include trial and error , asking for help from other users , and looking for information in printed and on-line documentation . This paper describes a cognitive model of exploratory learning , which covers both trial-and-error and instruction-taking activities . The model , implemented in Soar , is grounded in empirical data of subjects in a task-oriented , trial-and-error exploratory learning situation . A key empirical finding reflected in the model is the repeated scanning of a subset of the available menu items , with increased attention to items on each successive scan . This is explained in terms of dual search spaces , the external interface and the user's internal knowledge , both of which must be tentatively explored with attention to changing costs and benefits . The model implements this dual-space search by alternating between external scanning and internal comprehension , a strategy that gradually shifts its focus to a potentially productive route through an interface . Ways in which interfaces might be designed to capitalize on this behaviour are suggested . The research demonstrates how cognitive modelling can describe behaviour of the kind discussed by theories of ''situated cognition'' .