The fan effect: New results and new theories

The fan effect (J. R. Anderson, 1974) has been attributed to interference among competing associations to a concept. Recently, it has been suggested that such effects might be due to multiple mental models (G. A. Radvansky, D. H. Spieler & R. T. Zacks, 1993) or suppression of concepts (M. C. Anderson & B. A. Spellman, 1995; A. R. A. Conway & R. W. Engle, 1994). It was found that the Adaptive Control of Thought-Rational (ACT-R) theory, which embodies associative interference, is consistent with the results of G. A. Radvansky et al. and that there is no evidence for concept suppression in a new fan experiment. The ACT-R model provides good quantitative fits to the results, as shown in a variety of experiments. The 3 key concepts in these fits are (a) the associative strength between 2 concepts reflects the degree to which one concept predicts the other; (b) foils are rejected by retrieving mismatching facts; and (c) participants can adjust the relative weights they give to various cues in retrieval.