Abstract
Previous research has shown that salient, exogenous cues that do not contain the target's defining attribute usually do not cause a spatial cuing effect in mean RT. This is most readily explained by the Contingent Capture hypothesis under which incongruent cues do not capture attention at all. However, we've observed data that do not conform to the strict version of this hypothesis in that we have found small, but reliable, spatial cuing effects on trials with incongruent cues. In particular, we have found spatial cuing effects on incongruent trials that are about one third as large as those on congruent trials. One possibility is that a subset of our subjects happened to approach the task in a different way from the others. That is, approximately one third of the subjects may have set their attention to be captured by the most salient stimulus or singleton (which would produce effects for both congruent and incongruent cues), while the others were set for the specific feature that defined the target (and would only produce effects for congruent cues). To test this possibility, we examined the data on a subject-by-subject basis, instead of conducting our analyses on the grand averages. If the idea put forth above is true, then the data should exhibit a clear separation between those who were set for any salient singleton and those who were set for the target (only). However, this pattern was not found. Rather, scatter plots of the congruent vs incongruent cuing effects were homogenous, suggesting that incongruent cues capture attention on at least some trials for all subjects, or weakly on every trial.
This project has been supported by Grants-in-Aid of Research for Doctoral Dissertations awarded by Sigma Xi, and Dissertation Support awarded by the College of Liberal Art, the Pennsylvania State University.