Two Types of Attentional Footprint: Feature-based Enhancement and Suppression Leave Persisting Spatial Effects

Abstract

Both target-feature enhancement and distractor-feature suppression can flexibly guide attention (Chang & Egeth, 2019). Although such effects are feature-driven, here we explore the possibility that enhancement and suppression effects persist at the locations where critical features were presented even when the features are no longer present. In the current study, search and probe trials were randomly interleaved. Participants searched for a diamond target among other shapes on half of trials (search trials) and searched for a probe target, either ‘A’ or ‘B’, among other letters on the other half of trials (probe trials). On search trials, two items including the diamond target were always in a target color while the other two items were in a distractor color. Color roles were consistent across trials. On probe trials, four ovals were presented, one of which was in either a target or distractor color and the other three ovals were in neutral colors that never appeared on search trials. Participants learned the target and distractor features through search trials while probe trials assessed the underlying attentional template that guided visual search. In Experiment 1, on probe trials letters were presented on the ovals. On target-color-present trials, a probe target on a target-colored oval was identified faster than one on a neutral-colored oval, showing target-feature enhancement. On distractor-color-present trials, a probe target on a distractor-colored oval was identified slower than one on a neutral-colored oval, showing distractor-feature suppression. More interestingly, in Experiment 2 substantial enhancement and suppression effects were observed even when the ovals were removed 1,500 ms before the presentation of the probe letters. The probe letters appeared on a blank background in the locations that had been occupied by critical (target- or distractor-colored) or neutral ovals. Feature-based enhancement and suppression leave persisting spatial effects in locations vacated by critical features.