LIST-STRENGTH AND LIST-LENGTH EFFECTS - REPLY

R. M. Shiffrin, R. Ratcliff, K. Murnane, and P. Nobel (1993) claimed that TODAM (a theory of distributed associative memory) is unable simultaneously to predict an absent (or negative) list-strength effect (LSE) and a positive list-length effect (LLE). However, Shiffrin et al. failed to distinguish between situations in which lag (number of items intervening between study and test) is controlled and situations in which it is not. We stand by our previous conclusion; TODAM can explain why there is little or no LSE when at the same time there is an LLE when the LLE is studied under the standard conditions. To our knowledge there are no published studies where lag has been controlled. However, this simplified version of TODAM cannot explain an LLE when a scoring window is used. Whether such a result would be inconsistent with a more complete version of TODAM remains to be seen.