Memory and the theory of signal detection.

A recurrent problem in the study of recognition memory has been that of combining hits and false alarms (or correct and incorrect responses) into a single index of performance. That the proportion of correct responses in a yes/no or multiple-choice recognition test may in some way be contaminated by factors other than the state of the memory system has never been seriously disputed, but only recently has the question received detailed and systematic attention. Traditionally the problem has been viewed in terms of correcting for chance success; in current terminology, and stated more generally, it is a problem of providing an adequate theory of the decision system which maps a given state of the memory system into an overt response. The reasons for this increased attention to decision processes in memory are not difficult to trace. In the first place, the development of quantitative theories of recognition memory has necessitated a precise and explicit account of how the memory and decision systems interact to produce a given response. If a theory of memory is to be tested against data from a recognition-me mory experiment, it is necessary to obtain performance measures that are independent of those parameters