Abstract
There is ongoing debate as to whether distraction by salient irrelevant objects can be avoided and in particular, about whether their salient features can be proactively suppressed. Recently, Lamy (2021) suggested that a central reason for this stalemate is methodological: researchers often base their conclusions on net capture/suppression effects instead of investigating how manipulating inhibitory suppression modulates these effects. Here, we provide empirical evidence for this observation by revisiting the findings by Wang and Theeuwes (2020). These authors found that a color singleton distractor produced net capture with dense search displays, where the singleton is highly salient, and net suppression with sparse displays, where the singleton is less salient. They concluded that only mildly salient distractors can be suppressed. Here, in two experiments, we orthogonally manipulated distractor salience and feature-based suppression. Participants searched for a shape and a color singleton distractor was sometimes present. Search displays were either sparse or dense and the singleton’s color changed on each block. Distractor feature-based suppression was measured as a reduction in distractor interference in the second relative to the first half of each block. We replicated Wang and Theeuwes’ findings but invalidated their interpretation: the singleton distractor interfered more in dense vs. sparse displays but, crucially, in both display densities, the distractor interfered less as participants accumulated experience rejecting its color; participants learned to suppress the color singleton equally well regardless of the distractor’s salience. Our findings indicate that a distractor’s relative salience and the feature-based suppression applied to it jointly determine its attentional priority and that net capture/suppression effects do not reflect qualitatively distinct mechanisms. We hope that the current findings will encourage researchers to “focus on the mechanisms that guide attention instead of hunting the conditions that give rise to net capture or to suppression effects” (Lamy, 2021).