| Abstract: | The goal of this study was to establish some of the conditions under which mental imagery facilitates or interferes with the identification and detection of visual patterns. In Experiment 1, subjects identified simple bar patterns presented at orientations 90 degrees apart under normal viewing conditions. Their reaction times were shorter when they had imagined seeing the patterns in advance at the same orientation, but were longer when they had imagined seeing the patterns at orientations that were in-between those of the actual presented patterns, relative to baseline conditions in which they were instructed not to imagine the patterns. In Experiment 2, where the subjects had only to detect the target patterns without identifying them, there was no effect of image formation or image-target alignment. In Experiment 3, where the detection task was repeated but where the target exposure duration was reduced, imagery significantly interfered with detection. In contrast to the results of Experiment 1, reaction time and error rate in this case were greatest when the imagined patterns were perfectly aligned with the target patterns. These findings demonstrate that whether imagery facilitates or interferes with performance on a visual task depends on the nature and difficulty of the task and on how closely the imagined and presented patterns correspond. |
