Analysis of a constraint on perception, cognition, and development: one object, one place, one time
Related Experiment Video
Updated: Aug 21, 2026

Creating Objects and Object Categories for Studying Perception and Perceptual Learning
Published on: November 2, 2012
1Department of Psychology, University of Arizona, Tucson 85721, USA. bedford@u.arizona.edu
Abstract:
It has become increasingly common for theories to rely on a constraint that 1 object cannot be in more than 1 place at the same time. Analysis suggests that a 1 object-1 place-1 time constraint as literally stated is false, that a modified constraint is biased toward the visual modality, that it may not be a correct description of the physical world, is not true of how objects must appear on sensory surfaces, and does not mean that 2 simultaneous spatially separated samples must be interpreted as 2 different objects, even for vision. However, once such object numerosity or identity is determined in some other way, then a modified constraint can be used to trigger learning, such as prism adaptation. A far-removed implication is that "Where is an object?" may be a misleading question.
More Related Videos
Related Concept Videos
Gestalt Principles of Perception
Piaget's Stage 1 of Cognitive Development
Exploration...
Perceptual Constancy
Size constancy is the recognition that an object remains the same size, even when its image on the retina changes. For instance, a bus is perceived to be large enough to carry people, even if it looks tiny from...
The Nativist Approach
Piaget's Stage 2 of Cognitive Development
Cognitivism
Previously dominated by behaviorism, which prioritized observable behaviors and largely ignored mental processes, psychology transformed in the 1950s. Cognitive psychologists argue that understanding how we think and process information is...

