The systematic discrepancy between A′ for overall recognition and remembering: A dual-process account

Signal detection accounts of recognition assume that all item endorsements arise from the assessment of a single continuous indication of memory strength, even when subjects claim to categorically separate items accompanied by contextual recollection from those that are not (viz., remembering vs. knowing). Dissociations of these response types are held to occur because the former require a higher response criterion for item strength than does the latter. Meta-analytic and individual subject data suggest that when the A′ metric is used, accuracy for remembering can systematically deviate from that of over-all responding for individual subjects. This occurs because, unlike the symmetric and rigid receiver-operating characteristic (ROC) implied under A′, empirical ROCs are asymmetric and plastic. A dual-process model predicted that the magnitude of the deviation would vary as a systematic function of the proportion of overall recognition accompanied by subjective remember reports for individual subjects. The predictions were confirmed using multiple regression on Monte Carlo and experimental data sets and were also shown to generalize to the double equal-threshold, single high-threshold [i.e., H - FA; (H - FA)/(1 - FA)], and the equal variance signal detection d′ corrections. The unequal variance signal detection model was also shown to mirror the data, but only under the post hoc assumption that every subject adopts a very similar remember criterion placement rule. The results demonstrate that the systematic failure of tightly constrained models of recognition constitutes valuable regression data for more complex models and simultaneously highlights why single-point measures of accuracy are unsuitable as summaries across conditions or groups. Furthermore, the results show that remember rates carry unique information regarding the underlying processes governing individual subject performance that cannot be gleaned from the overall hit and false alarm rates in isolation. This research was supported in part by the National Institutes of Health. I thank Russell Poldrack, Anthony Wagner, and Andrew Yonelinas for their reviews of an earlier version of this manuscript.