Distractor-interference reduction is dimensionally constrained

• Published in: Visual cognition Vol. 27; no. 3-4; pp. 247 - 259
• Main Authors: Liesefeld, Heinrich René, Liesefeld, Anna M., Müller, Hermann J.
• Format: Journal Article
• Language: English
• Published: Hove Routledge 21.04.2019; Taylor & Francis Ltd
• Subjects: additional-singleton task; Attention; Attentional capture; Delayed response; dimension-weighting account; distractor handling; Orientation behavior; Visual perception; visual search
• ISSN: 1350-6285; 1464-0716
• DOI: 10.1080/13506285.2018.1561568

The dimension-weighting account predicts that if observers search for a target standing out from the background in a particular dimension, they cannot readily ignore a distractor standing out in the same dimension. This prediction is tested here by asking two groups of observers to search for an orientation target or a luminance target, respectively, and presenting an additional distractor defined in either the respectively same dimension or the other dimension. Notably, in this cross-over design, the physically identical distractors served both as same- and different-dimension distractors, depending on target condition. While same-dimension distractors gave rise to massive interference, different-dimension distractors caused much weaker (though still substantial) interference. This result is most readily explained by the dimension-weighting account: different-dimension distractors are considerably down-weighted but not fully suppressed. Furthermore, same- and different dimension distractors delayed response times even when considering only the fastest (down to 2.5%) of trials, indicating that interference is exerted consistently on each trial, rather than probabilistically on some trials. Our results put strong constraints on models of distractor handling in visual search.