Three studies explored how the influence of the ‘availability heuristic’ on frequency judgement is mediated and moderated by the perceived meaning of the task, the perceived relevance of information for the task, and the salience of differential memorability of information. All studies adapted the ‘fumous names ’paradigm (Tversky and Kahneman, 1973) in which subjects are required to listen to a list of names of known personalities of both sexes and then judge the frequency of men and women. The availability heuristic (Tversky and Kahneman, 1973) posits that classes whose instances are easy to imagine or recall will be perceived as relatively frequent, so that when names of one sex are more famous and thus memorable this category will be rated as more numerous even when it occurs less frequently. Consistent with the notion that the use of availability is sensitive to task interpretation, we showed that the availability effect is eliminated over successive trials (Study 1) and moderated when task instructions render different categories salient (Study 2). In the third study it is shown that conditions which facilitate awareness of the biasing relationship between gender and fame (memorability), decrease the use of the availability heuristic by moderating frequency estimates of the more famous category. Results of these studies emphasize the context-bound and strategic aspects of judgement.