Strategies for Generating Multiple Instances of Common and Ad Hoc Categories FreÂdeÂric ValleÂe-Tourangeau, Susan H. Anthony, and Neville G. Austin University of Hertfordshire, UK In a free-emission procedure participants were asked to generate instances of a given category and to report, retrospectively, the strategies that they were aware of using in retrieving instances. In two studies reported here, participants generated instances for common categories (e.g. fruit ) and for ad hoc categories (e.g. things people keep in their pockets ) for 90 seconds and for each category described how they had proceeded in doing so. Analysis of the protocols identified three broad classes of strategy: (1) experiential , where memories of specific or generic personal experiences involving interactions with the category instances acted as cues; (2) semantic , where a consideration of abstract conceptual characteristics of a category were employed to retrieve category exemplars; (3) unmediated , where instances were effortlessly retrieved without mediating cognitions of which subjects were aware. Experiential strategies outnumbered semantic strategies (on average 4 to 1) not only for ad hoc categories but also for common categories. This pattern was noticeably reversed for ad hoc categories that subjects were unlikely to have experienced personally (e.g. things sold on the black market in Russia ). Whereas more traditional accounts of semantic memory have favoured decontextualised abstract represen- tations of category knowledge, to the extent that mode of access informs us of knowledge structures, our data suggest that category knowledge is significantly grounded in terms of everyday contexts where category instances are encoun- tered. INTRODUCTION The studies reported here concern the nature of the strategies people spontaneously use when asked to retrieve instances for a given category. Item retrieval during this so-called ``free emission’’ procedure appears to reflect MEMORY, 1998, 6 (5), 555±592 Requests for reprints should be sent to FreÂdeÂric ValleÂe-Tourangeau, Department of Psychology, University of Hertfordshire, Hatfield, Hertfordshire, UK, AL10 9AB. E-mail: psyqfv@herts.ac.uk A partial report of these data was presented at the BPS Cognitive Section XII Annual Conference, Bristol, September 1995. Ó 1998 Psychology Press Ltd