Abstract
Visual masking refers to a phenomenon that a briefly presented stimulus (target) could be rendered less visible or totally invisible by the presentation of a second stimulus (mask). Evidence shows that similarity between target and mask enhances masking effect, but in a selective way. Specifically, similarity in one visual property deteriorates the target perception on this property but leaves masking for other properties unaffected. Here we show that similarity based on topological property (e.g. the number of holes) has distinctive effect on masking. We manipulated the topological similarity between target and mask and investigated the topological similarity effects in both topology-relevant (i.e. discriminating between no-hole and one-hole stimuli) and irrelevant (e.g., discriminating color) tasks. We found that topological similarity affected masking not only of the topological property itself but also of other properties, while the similarity of non-topological properties (e.g. color and shape) only affected masking of the properties themselves. This trend also existed when we used one-hole and two-hole stimuli to represent topological difference. The potential confounding such as luminous flux and shape, which might co-vary with topological manipulations, could be ruled out by adopting area-matched stimuli and the further analyses revealing no effect from shape difference when target and mask had the same topological property. Our results suggest that topological property has precedence over other properties in visual processing, and masking effect might be divided into two levels: feature level (e.g., color and shape) and object level which is determined by topological property.
Meeting abstract presented at VSS 2012