| Abstract: | Signal detection theory (SDT) requires that the slope of the receiver operating characteristic (ROC) is independent of the probability of signal and noise. But it has been shown that when the rating procedure is applied to detection, the slope of the receiver operating characteristic may increase as a function of the probability of the signal (Schulman & Greenberg, 1970). This presents a serious problem for signal detection theory. This problem is examined in relation to a recent theory of criterion setting (Treisman & Williams, 1984), and an explanation for the effect of signal probability on ROC slope is derived which is compatible with SDT. Further data on the relation between signal probability and ROC slope are reported. |
