The competition between grouping cues can be resolved under inattention

We investigated whether attention is required for the resolution of the competition between conflicting grouping cues. Participants performed a demanding change-detection task on a small matrix presented on a backdrop composed of two organizations that could change or stay the same between two consecutive displays independently from changes in the target. We hypothesized that if the competition between the backdrop organizations can be resolved without attention, congruency effects should emerge between changes in the target and changes in the organization that won the competition, but not for the other organization. Three trial types were examined: no-conflict trials, where the two grouping cues formed the same organization (e.g., columns by proximity and by color similarity); conflict trials, where the two cues formed conflicting organizations (e.g., columns by proximity and rows by color similarity); and mixed trials, where one backdrop display depicted no conflict while the other depicted conflicting organizations. Congruency effects were elicited by one organization (Experiment 1-proximity, Experiment 2-common region) but not by the other (color similarity, Experiments 1-2), in the no-conflict and mixed trials, suggesting that if one display in a trial was well organized it facilitated the resolution of the competition in the other display. However, when resolving the competition was required for both displays within a trial, it was not accomplished without attention. Thus, this study shows novel results revealing some of the conditions in which the competition between grouping cues can be resolved without attention.