Memory search without interference: The role of integration

Several researchers have shown that the time required to retrieve a sentence increases with the number of unrelated facts learned about concepts in that sentence. L. M. Reder and J. R. Anderson (1980, Cognitive Psychology, 12, 447–472) have argued that such fan effects also occur when the facts are integrated, provided that subjects must carry out a search of memory. In the present set of three experiments, we followed Reder and Anderson's procedure but, in a highintegration condition, used facts that were causally linked. In the first experiment, recall and recognition accuracy were better when fan was six than when it was three, and this effect was more pronounced in a high- than in a low-integration condition. In the second experiment, the overall fan effect was negative for recognition time in the high-integration condition, whereas in the low-integration condition, we obtained the usual positive fan effect. In the third experiment, subjects learned the materials on their own to provide a better opportunity for them to integrate facts. All fan effects became smaller or more negative relative to those observed in the preceding study. We consider a class of models for the findings in which subjects use confirming and disconfirming evidence as a basis for early termination of search.