The availability heuristic proposes that the phenomenal experience of ease of recall serves as a source of information in making frequency or probability judgments. However, ease of recall and amount of recall have typically been confounded in empirical tests. A misattribution approach was used to isolate the impact of the phenomenal experience. As expected, subjects provided the lowest frequency estimates when they believed that an irrelevant context variable facilitated recall, and the highest estimate when they believed that a context variable inhibited recall. Thus, their judgments were mediated by the perceived diagnosticity of the phenomenal experience of ease of recall, as predicted by the availability heuristic.