Spontaneous discounting of availability in frequency judgment tasks.

Discounting is a causal-reasoning phenomenon in which increasing confidence in the likelihood of a particular cause decreases confidence in the likelihood of all other causes. This article provides evidence that individuals apply discounting principles to making causal attributions about internal cognitive states. In particular, the three studies reported show that individuals will fail to use the availability heuristic in frequency estimations when salient causal explanations for availability exist. Experiment 1 shows that fame is used as a cue for discounting in estimates of surname frequency. Experiment 2 demonstrates that individuals discount the availability of their own last name. Experiment 3, which used individuals' initials in a letter-frequency estimation task, demonstrates that simple priming of alternative causal models leads to discounting of availability. Discounting of cognitive states can occur spontaneously, even when alternative causal models are never explicitly provided.