Estimating the frequency of events from unnatural categories.

We report two experiments about how people estimate the frequency of event properties when they are explicitly (e.g, spinach-GREEN) and implicitly (e.g, spinach) presented. In Experiment 1, verbal reports indicated that, for explicitly presented properties, participants used several retrieval- and impression-based strategies and were relatively accurate. Implicitly presented properties led to off-target retrieval, which brought to mind more instances of nontarget than of target properties and degraded estimates. A third group estimated the frequency of taxonomic categories (e.g., furniture) much as the explicit property group did, suggesting that people can use properties to organize remembered events. In a second experiment, estimation time patterns underscored the results of Experiment 1 and eliminated reactive verbal reports as an explanation. Off-target retrieval was both ineffective and slow.