Strategy use in question-answering: memory strength and task constraints on fan effects.

Abstract

The time taken to recognize a studied fact increases as a function of the number of other previously studied facts sharing concepts with the test fact. The phenomenon, known as the “fan effect,” has been shown to disappear and sometimes even reverse itself when the set of facts are thematically related. The shift from interference toward facilitation occurs only when subjects can use a plausibility-like strategy. In this experiment, subjects learned variously sized sets of rehted facts about fictitious people. Subjects were asked to make either recognition judgments (“Did you study this fact?”) or consistency judgments (“Is this fact consistent with what you studied7”). Subjects made these judgments both the day the material was acquired and 2 days later. The research reported here supports the hypothesis that, with delay, there is a shift in tendency toward more use of the plausibility strategy, away from the careful strategy of searching for an exact match that produces the fan effect. The plausibility strategy produced either a speedup with greater fan or an increase in error rates when the strategy was inappropriate. Plausibility effects were larger at a delay, in both reaction time and error patterns, regardless of whether subjects were asked to make consistency judgments or recognition judgments. Also as predicted, response times became faster as the tendency to adopt the plausibility strategy without first trying direct retrieval increased.