Related Experiment Video
Updated: Jun 29, 2026

Ultrasound Imaging of the Thoracic and Abdominal Aorta in Mice to Determine Aneurysm Dimensions
Published on: March 8, 2019
Are mirror-symmetric objects of special importance for 3D shape perception? A reply to Sawada and Pizlo (2022)
Alexander A Petrov1,2, Ying Yu1,3, James T Todd1,4
1Department of Psychology, The Ohio State University, Columbus, OH, USA.
Abstract:
Yu, Todd, and Petrov (2021) and Yu, Petrov, and Todd (2021) investigated failures of shape constancy that occur when objects are viewed stereoscopically at different distances. Although this result has been reported previously with simple objects such as pyramids or cylinders, we examined more complex objects with bilateral symmetry to test the claim by Li, Sawada, Shi, Kwon, and Pizlo (2011) that the perception of those objects is veridical. Sawada and Pizlo (2022) offer several criticisms of our experiments, but they seem to suggest that the concept of shape is defined by what is computable by their model. If stimuli are used that cannot be discriminated by their model, they are dismissed as degenerate, and tasks that cannot be performed by their model are assumed to be based on something other than shape. This allows them to disregard empirical evidence that is inconsistent with their model. We argue, in contrast, that all reliable aspects of shape perception are deserving of explanation. We also argue that there are many different attributes of shape and many different sources of information about shape that may be relevant in different contexts. It is unlikely that all of them can be explained by a single model.
More Related Videos
Related Concept Videos
Chirality
Chiral objects exhibit a sense of handedness when they interact with another chiral object. For example, our left foot can only fit in the left shoe and not in the right shoe. Achiral objects — objects that have...
Stereoisomers
Plastic Deformations of Members with a Single Plane of Symmetry
Depth Perception and Spatial Vision
Gestalt Principles of Perception
The Looking Glass Self

