Abstract
Introduction: Whether attention intensifies the subjective perception of sensory attributes has been a topic of debate in experimental psychology for over one hundred years. Recently, some studies have shown that transient peripheral attentional cues can increase the perceived contrast and other attributes of stimuli. These studies have been interpreted as demonstrating a link between neural theories and the phenomenology of attention. In a previous study, we were unable to reproduce the effect of attention on perceived contrast except for very low contrasts, near the threshold of detection, and the characteristics of those effects suggested they were the result of sensory interactions between the cues and targets rather than attention. To further investigate the discrepancy, we decided to replicate published studies, using their exact superthreshold stimuli and procedures, and also to introduce different types of behavioral judgments.
Methods: Two Gabor patch targets with separate contrasts were simultaneously and briefly presented. One was pre-cued by a transient small black dot. Fourteen subjects compared the contrasts of the two targets using three different types of perceptual judgments in separate sessions: 1. whether the two targets had the same or different contrast (equality judgment); 2. which target had the higher contrast (comparative judgment); 3. the comparative judgment plus determining the orientation of the target deemed to have the higher contrast.
Results: The two comparative judgments showed significant increases in contrast of the cued target across the range of contrasts tested. However, the equality judgment showed no effect at any contrast.
Conclusion: The equality judgment is not susceptible to the same type of biases as the comparative judgment. Since the attentional effects depend on the decision process, we must conclude that while attention may incite post-perceptual biases in the decision process, it does not prohibit the veridical perception of sensory attributes—attention does not deceive us.