Related Experiment Video
Updated: Nov 15, 2025
07:08
Investigating Object Representations in the Macaque Dorsal Visual Stream Using Single-unit Recordings
Published on: August 1, 2018
8.5K
Size constancy affects the perception and parietal neural representation of object size
Stephanie Kristensen1, Alessio Fracasso2, Serge O Dumoulin3
1Faculty of Psychology and Education Sciences, University of Coimbra, Rua do Colégio Novo, 3000-115 Coimbra, Portugal.
Neuroimage
|March 2, 2021
Summary
Object size perception is biased by recently viewed sizes, with perceived sizes drawn towards the average and previous trial sizes. This attraction affects both perception and neural representations in the parietal cortex.
Area of Science:
- Neuroscience
- Cognitive Science
- Visual Perception
Background:
- Accurate object size perception is crucial for guiding behavior in humans and animals.
- Size constancy compensates for varying retinal image sizes due to distance, influenced by recent visual context.
- Previous research identified topographic object size maps in the human parietal cortex.
Purpose of the Study:
- To investigate how the range of recently viewed object sizes affects perceived object size.
- To determine if neural representations of object size in the parietal cortex are attracted towards recently viewed sizes.
- To explore the underlying neural mechanisms of context-dependent object size perception.
Main Methods:
- Utilized ultra-high-field (7T) functional MRI to measure neural representations of object size.
- Employed population receptive field modeling to analyze object size representations.
- Compared neural responses to small (0.05-1.4° diameter) and large (0.1-2.8°) object sizes.
Main Results:
- Demonstrated systematic biases in object size perception, including central tendency and serial dependence.
- Found that parietal object size preferences and tuning widths are attracted towards the presented range of sizes.
- Observed that neural representations change less than the presented object sizes, indicating an attraction bias.
Conclusions:
- Perception and neural representation of object size are attracted towards recently viewed sizes.
- This context-dependent representation in the parietal cortex influences object size perception.
- The findings reveal how recent visual context shapes neural processing and perceptual outcomes.
Related Concept Videos
01:12Perceptual Constancy
916
Perceptual constancy is the ability to recognize that objects remain consistent and unchanged even when their appearance varies due to changes in sensory input. There are four main types of perceptual constancy: size constancy, shape constancy, color constancy, and brightness 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...
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...
916
01:15Depth Perception and Spatial Vision
1.4K
Depth perception is the ability to perceive objects three-dimensionally. It relies on two types of cues: binocular and monocular. Binocular cues depend on the combination of images from both eyes and how the eyes work together. Since the eyes are in slightly different positions, each eye captures a slightly different image. This disparity between images, known as binocular disparity, helps the brain interpret depth. When the brain compares these images, it determines the distance to an object.
1.4K
01:25Factors Affecting Perception
2.2K
Perception is influenced by perceptual set, context, motivation, and emotion. Perceptual set, or perceptual expectancy, refers to the tendency to perceive things in a particular way, influenced by previous experiences and expectations. This phenomenon affects the interpretation of stimuli, creating a set of mental tendencies and assumptions that impact sensory perceptions of sound, taste, touch, and sight.
An illustrative example of a perceptual set is the scenario where an airline pilot told...
An illustrative example of a perceptual set is the scenario where an airline pilot told...
2.2K
01:21Gestalt Principles of Perception
795
Gestalt principles provide a framework for understanding how humans perceive objects as unified wholes within their context. These principles are essential in explaining the cognitive processes that make sense of complex visual stimuli by organizing them into coherent groups. One fundamental principle is proximity, which posits that objects located close to each other are perceived as a collective group. For instance, when dots are positioned near one another, the visual system interprets them...
795
01:28Perception
797
Perception is a fundamental psychological process that enables individuals to organize, interpret, and consciously experience sensory information. This process is crucial for understanding and interacting with the world around us. It includes both bottom-up and top-down processing, each playing a distinct role in how we perceive our environment.
Bottom-up processing begins at the sensory level, where receptors detect external environmental stimuli. These could include the tactile sensation of...
Bottom-up processing begins at the sensory level, where receptors detect external environmental stimuli. These could include the tactile sensation of...
797
01:33Somatosensation
42.0K
The somatosensory system relays sensory information from the skin, mucous membranes, limbs, and joints. Somatosensation is more familiarly known as the sense of touch. A typical somatosensory pathway includes three types of long neurons: primary, secondary, and tertiary. Primary neurons have cell bodies located near the spinal cord in groups of neurons called dorsal root ganglia. The sensory neurons of ganglia innervate designated areas of skin called dermatomes.
42.0K