Object Closure Affects Attentional Filtering of Flanking Distracters

When visual information is selected for processing based on its relationship to an object (e.g., a target letter within a rectangle), it’s due to object-based attention (OBA). We investigated how object closure affects the strength of OBA by measuring reaction times to letters presented on either closed or open objects. Displays contained five vertical, parallel rectangles upon which a set of letters appeared at both the top and bottom. Participants were asked to decide whether the green letter (always on the central object) was a ‘T’ or ‘L’. A 75% valid spatial cue appeared at one end of the central object before onset of the letters. In a separate condition, the rectangles were replaced by a series of parallel lines (the horizontal parts of the rectangles were removed) such that the objects appeared ‘open’. In Experiment 1, participants were presented with blocks in which all rectangles were either ‘closed’ or ‘open’. Results showed that object closure affected attentional filtering of distracting letters; ‘open’ objects led to more infiltration of distracters and ‘closed’ objects yielded less distraction. Experiments 2 and 3 tested whether attentional filtering was more affected by the closure of flanking objects versus the central object. Results suggest that closure of the central object increases resistance to distracter intrusion by keeping out interference from the central object; while flanker object closure restrains the influence of distracters on the central target by enclosing interference within flanking objects. Overall, these results suggest that the strength of object-based attentional selection can be modulated by the completeness of object representations. Thus, changes in low-level visual object information may determine the effectiveness of attentional selection. Funding: US-Israel Binational Science Foundation Grant No. 2013400 (A.S.G) and UWM SURF (G.N./A.S.G.