Does surface completion fail to support uncrowding?

Abstract

In crowding, perception of a target deteriorates in the presence of nearby elements. As the entire stimulus configuration across large parts of the visual field influences crowding and not just nearby elements, low-level explanations, such as local pooling, do not suffice. To explain the effects of stimulus configuration, grouping was proposed as the key, and we implemented these ideas in a neural network model (LAMINART). In a recent publication, Moore and Zheng (2024) used a set of stimuli designed to induce surface completion cues, such as occlusion, and found that they had no effect on crowding. Based on these results, the authors questioned the role of grouping in crowding. Here we show that the stimuli Moore and Zheng used do not induce the intended perceptual occlusion effects. Hence, their conclusions are not warranted. Additionally, simulations of the LAMINART model explain the results of Moore and Zheng with the existing model characteristics.