Superiority of recognition over detection in judgments of visual orientation

2 human subjects were tested in two separate visual psychophysical tasks--detection and recognition. Using tachistoscopic presentation, single lines were shown at five different exposure durations. It was determined that it is easier to judge which of two lines, differing only in orientation, was flashed than to judge whether or not a given line was presented. The statistically significant superiority of recognition over detection occurred along a wide performance range, roughly from 60% to 95% correct. The data indicate that the effect is not peculiar to a simultaneous detection-recognition task or to a midrange performance level, both of which were used in a previous study. Other relevant data and theoretical explanations of the effect are discussed.