On the importance of models in interpreting remember-know experiments: comments on Gardiner et al.'s (2002) meta-analysis

From a meta-analysis of recognition experiments using the remember-know-guess paradigm, Gardiner, Ramponi, and Richardson-Klavehn (2002) reported two findings that they viewed as evidence against the one-dimensional model for that paradigm: (1) Memory strength increased when know responses were added to remember responses, decreasing when guess responses were also included. (2) The accuracy of guess responses was correlated with the location of the old-new criterion in the one-dimensional model for the paradigm, implying that guesses were influenced by decision processes. We question both findings. The first result is contradicted by a signal-detection (SDT) analysis, which shows that both know and guess responses reduced estimated memory strength. The discrepancy results from the properties of A', the measure of accuracy used by Gardiner et al., which we argue is flawed. The second result follows directly from the one-dimensional model, in which accuracy and response criteria are fixed. The authors' reasons for rejecting the one-dimensional model are thus not persuasive, but it can nonetheless be rejected because ROC curves implied by the data are inconsistent with ROCs derived from ratings experiments. A two-dimensional SDT model (Rotello, Macmillan, & Reeder, 2004) accounts for both sets of data. The analysis illustrates the importance of models in interpreting remember--know data.