Abstract
Recent studies have shown spatial heterogeneity in the perception of multiple feature dimensions (Afraz, Pashkam, & Cavanagh, 2010), and also stable individual biases in object localization (Kosovicheva & Whitney, 2017). Considering the role of selective attention in visual perception (Boynton, 2005; Luck & Ford, 1998), we hypothesized that attentional capture would also exhibit spatial heterogeneity across display locations. In 3 experiments, we used modified versions of the additional singleton paradigm (Theeuwes, 1991, 1992) to test this hypothesis. In Experiment 1, distractors were defined on the color dimension. We tuned the relative saliency of the only color singleton into 5 levels using a linear interpolation method. A vertical segment or a horizontal segment was contained within the target form singleton, which appeared equally-often at each of the eight locations. After the location of the target was set, the color distractor appeared equally-often at the other seven locations. In Experiment 2 and 3, distractors were defined on the orientation and size dimension respectively. The five distractor saliency conditions were specified by the relative inclination of the line segment contained within one of the non-target stimuli in Experiment 2, and by the relative size of one of the non-target stimuli in Experiment 3. The results showed a unique spatial distractibility pattern for each participant, with RT (reaction time) at some display locations demonstrating significant differences between distractor-present and distractor-absent conditions while some not. The stability and distinctiveness of spatial heterogeneity for attentional capture susceptibility for each participant were demonstrated by the high within-individual effect size correlation between 2 rounds and the low between-individual effect size correlation across display locations. These findings suggest that stimuli displayed at some spatial locations seem to be intrinsically easier to capture attention, which offers further insights for understanding the relationship between visual attention and perception.