The effects of payoffs and prior probabilities on indices of performance and cutoff location in recognition memory

We compared the effects of payoffs and prior probability levels on indices of performance and cutoff location in recognition memory. The performance indices considered were d' from signal-detection theory and two corrections for guessing from simple threshold models. Shifts in cutoff location of comparable size were found for changes in priors and payoffs. The existence of a memory load and the inclusion of feedback did not affect the extent of shifts in cutoff location. Priors affected the corrections for guessing but did not affect d'. These results indicate that d' remains the preferred index of performance and that the corrections for guessing are not criterion-free measures. The problem of finding an index of recognition performance appropriate for comparing recall and recognition is discussed, as are alternative explanations for conservative cutoff placement.