Suresh, Thomasson, and Haberman, VSS abstract, 2017

Ensemble representations account for size constancy

Sneha Suresh, Sam Thomasson, & Jason Haberman

The natural environment is full of redundant visual information, which the visual system compresses into an ensemble representation by averaging features of groups of items. Ensemble perception has been shown to operate with remarkable flexibility — it combines information across a host of visual domains, extracts summary information in the absence of attention, and even integrates conceptual information into an ensemble representation (e.g., Pandita, Suresh, & Haberman, VSS, 2015). In the current set of experiments, we tested whether linear perspective cues might influence the perceived average size of a group of triangles. Adding distance cues to a set of objects should cause objects ‘in the distance’ to appear larger than objects without distance cues, due to size constancy heuristics. Although size constancy has been well characterized, there has been limited investigation into whether the ensemble calculus takes into account an individual item’s perceived size or its physical size (e.g., Im and Chong, 2009). Observers viewed sets of triangles with and without the context of linear perspective cues and judged whether a subsequently presented test triangle was larger or smaller than the average size of the preceding set. Results revealed that observers did, in fact, take size constancy into account when estimating the average size of the three triangles. That is, observers judged the average size of triangles appearing with linear perspective cues as larger than those triangles without the cues. These results point to the remarkable flexibility of ensemble perception, which seems to incorporate both physical and conceptual representations into the ensemble code.