Abstract
Whether attention affects appearance is an important debate since the beginning of psychology. The debate has been intensified by the seminal work of Carrasco, Ling, & Read, 2004, indicating that the attention driven by abrupt onset can improve the apparent contrast of a grating. Because of using a comparing task, their results were thought to be contaminated by response biases. Some researchers did not found consistent facilitating effects of attention on appearance by using a bias-free task – the equality judgment task (e.g. Schneider & Komlos, 2008). In addition, the cue of abrupt onset might induce attention-independent sensory interactions upon the following target and therefore interferes with the genius attentional effects. We examined how attention affects appearance in an experimental design with sensory interactions and response bias eliminated. Two rotating-dot surfaces were presented to the left and right of the fixation point. Attention was directed to one of the surface by briefly (200 ms) shifting the rotating dots upward or downward. Then the dots surfaces continued to rotate in the original direction for 100 ms and was followed by two gray target patches. We employed the bias-free equality judgment task (i.e., whether the two patches has the same luminance) to measure the PSE of the patch luminance on the valid or invalid side. The second task was to judge the shifting direction of the dots surface. The background was either black 0 cd/m2) or white (72 cd/m2). We found that the perceived luminance of the gray patch was attenuated by attention when the background was black, while it was boosted by attention when the background was white. These results indicate that attention improves the perceived contrast of a uniform patch, and cannot be explained by low-level sensory interaction and high-level response biases.
Meeting abstract presented at VSS 2017