Evidence for discrete-state processing in recognition memory.

We provide evidence that recognition memory is mediated by a detect-or-guess mental-state model without recourse to concepts of latent-strength or multiple-memory systems. We assess performance in a two-alternative forced-choice recognition memory task with confidence ratings. The key manipulation is that sometimes participants are asked which of two new items is old, and the resulting confidence distribution is unambiguously interpreted as arising from a guessing state. The confidence ratings for other conditions are seemingly the resultant of mixing this stable guessing state with an additional stable detect state. Formal model comparison supports this observation, and an analysis of associated response times reveals a mixture signature as well.