Purchase this article with an account.
Søren Kyllingsæk, Jocelyn L. Sy, Barry Giesbrecht; Understanding the Allocation of Attention when Faced with Varying Perceptual Load in Partial Report: A Computational Approach. Journal of Vision 2011;11(11):134. doi: 10.1167/11.11.134.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The allocation of visual processing capacity is a key topic in visual attention. Load Theory (LT, Lavie, 1995) proposes that allocation happens in two stages where resources are allocated to task-relevant stimuli in the first stage and any remaining capacity ‘spills over’ to task-irrelevant stimuli in the second stage. In contrast, the Theory of Visual Attention (TVA, Bundesen, 1990) proposes that allocation happens in a single step where capacity is allocated to all stimuli, both task-relevant and task-irrelevant, in proportion to their relative attentional weight. These models have three key differences: 1) LT predicts no effect of similarity between the task-irrelevant distractors and the target, TVA does; 2) LT predicts no effect of the number of task-irrelevant distractors, TVA does; and 3) LT predicts no change in performance when task-irrelevant distractors are absent, TVA does. We tested these divergent predictions in two partial report experiments in which the number and discriminability of task-irrelevant stimuli (Experiment 1) and perceptual load (Experiment 2) were manipulated. The results of Experiment 1 revealed performance decrements when the number of flankers was increased and performance enhancements when the discriminability between the target and the flankers was increased. The results of Experiment 2 replicated and extended the findings of Experiment 1, while also showing nonlinear interaction between the effects of perceptual load and the number of task-irrelevant flankers. Quantitative TVA model fits captured the patterns in the behavioral data, while also showing that that the effects of varying perceptual load can only be explained by a combined effect of allocation of processing capacity as well as limits in visual working memory. Considered together our behavioral and computational modeling results are inconsistent with two-stage allocation scheme proposed by LT, but rather are consistent with the straightforward predictions made by the single stage allocation scheme proposed by TVA.
This PDF is available to Subscribers Only