Contingent Capture Is Weakened in Search for Multiple Features From Different Dimensions

Can observers maintain more than 1 attentional set and search for 2 features in parallel? Previous studies that relied on attentional capture by irrelevant distractors to answer this question focused on features from the same dimension and specifically, on color. They showed that 2 separate color templates can guide attention selectively and simultaneously. Here, the authors investigated attentional guidance by 2 features from different dimensions. In three spatial-cueing experiments, they compared contingent capture during single-set versus dual-set search. The results showed that attention was guided less efficiently by 2 features than by just 1. This impairment varied considerably across target-feature dimensions (color, size, shape and orientation). Confronted with previous studies, our findings suggest avenues for future research to determine whether impaired attentional guidance by multiple templates occurs only in cross-dimensional disjunctive search or also in within-dimension search. The present findings also showed that although performance improved when the target feature repeated on successive trials, a relevant-feature cue did not capture attention to a larger extent when its feature matched that of the previous target. These findings suggest that selection history cannot account for contingent capture and affects processes subsequent to target selection. Public Significance Statement Can we search for 2 things at once? Recent studies suggest that we can search for 2 different colors simultaneously, based on the finding that only objects matching these colors grab our attention. However, it remains possible that instead of maintaining 2 goals in parallel, observers in these studies alternated from 1 goal to the other. Here, the authors addressed this issue when observers searched for a target matching 1 of 2 features defined on different dimensions (color or shape, color or size, size or orientation). They found that although observers could search for 2 properties at a time, their search was less efficient and less selective than when they searched for only 1 object property. These findings thus reveal a structural limitation of our attentional system.