Detection and recognition of visual targets

To aid the development of detection-based interpretations of visual resolution, we evaluated theorems that (1) relate observers' performance in detection of a single target to that in 1-of-m signal detection and (2) predict recognition performance from measured performance at 1-of-m detection. These theorems require that the sensory effects of the stimuli be continuous and that the m signals be equally detectable and mutually orthogonal. To evaluate the theorems, we tested observers in simple detection, 1-of-m detection, and recognition of Landolt C targets and compared predicted and observed performance. Predictions of 1-of-m detection performance from that for simple detection and predictions of recognition from the 1-of-m receiver operating characteristic (ROC) were both accurate to within 0.03 in P(A). In addition, predictions of recognition based on the 1-of-m ROC predicted from simple detection were generally accurate. Thus, under restricted experimental conditions, recognition is determined completely by that for simple detection.