This article addresses J. R. Anderson and L. M. Reder's (1999) account of the differential fan effect reported by G. A. Radvansky, D. H. Spieler, and R. T. Zacks (1993). The differential fan effect is the finding of greater interference with an increased number of associations under some conditions, but not others, in a within-subjects mixed-list recognition test. Anderson and Reder concluded that the differential fan effects can be adequately explained by assuming differences in the weights given to concepts in long-term memory. When a broader range of data is considered, this account is less well supported. Instead, it is better to assume that the organization of information into referential representations, such as situation models, has a meaningful influence on long-term memory retrieval.