Abstract
Do salient items—such as color singletons—automatically capture attention? This seemingly simple question has been heatedly debated. As a potential resolution, the signal suppression hypothesis proposes that salient stimuli attract attention but can be ignored via an inhibitory mechanism. Recently, the signal suppression hypothesis has been challenged on the grounds that only weakly salient distractors produce suppression. According to this salience-driven view, increasing the salience of a distractor will enable it to overpower suppression and automatically capture attention. This claim has been difficult to empirically test because there are no established methods for measuring salience. In the current study, we introduce a psychophysical technique to measure perceptual salience. This technique was used to develop stimulus displays that contained low- and high-salience color singletons. We then tested whether these singletons captured attention or were instead suppressed when they were distractors in a visual search task. The results indicated that, if anything, high-salience singletons were easier to ignore than low-salience singletons. These findings directly challenge salience-driven accounts by demonstrating that highly salient color singletons can be suppressed and do not automatically capture attention.