Related Experiment Video
Updated: Jun 7, 2026
06:46
Investigating the Deployment of Visual Attention Before Accurate and Averaging Saccades via Eye Tracking and Assessment of Visual Sensitivity
Published on: March 18, 2019
Inconsistency between peri-saccadic mislocalization and compression: evidence for separate "what" and "where" visual
Gang Luo1, Tyler Garaas, Marc Pomplun
1Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, USA. gang.luo@schepens.harvard.edu
Journal of Vision
|November 5, 2010
Summary
Neurophysiological evidence suggests separate "what" and "where" visual systems. This study provides direct psychophysical evidence in neurologically intact individuals, showing distinct processing of object size and location.
Area of Science:
- Cognitive Neuroscience
- Visual Perception
- Psychophysics
Background:
- The dual-stream hypothesis posits separate visual pathways for object recognition ('what') and spatial processing ('where').
- While neurophysiological data support this, direct psychophysical evidence in humans is limited.
- Understanding these distinct visual processing streams is crucial for comprehending visual cognition.
Purpose of the Study:
- To provide direct psychophysical evidence for the separation of 'what' and 'where' visual processing in neurologically intact individuals.
- To investigate whether perceived object size and location are processed independently during rapid eye movements (saccades).
Main Methods:
- A peri-saccadic perception paradigm was employed, presenting bars of varying lengths around saccade onset.
- Researchers measured perceived object size ('what' attribute) and perceived object location ('where' attribute).
- The study analyzed how these attributes are affected by saccadic eye movements.
Main Results:
- Perceived object location demonstrated significant compression, shifting towards the saccade target.
- In contrast, perceived object size did not exhibit similar compression.
- This dissociation between location and size perception was observed consistently.
Conclusions:
- The findings provide direct psychophysical evidence supporting the independent processing of 'what' and 'where' visual attributes.
- Perceived object size is not solely determined by its spatial localization, reinforcing the dual-stream model.
- This research contributes to our understanding of visual system organization and function in humans.
Related Concept Videos
01:26Visual System
Light enters the eye through the cornea, a transparent, dome-shaped surface covering the surface of the eyeball that helps to direct and focus incoming light. This light is then channeled toward the pupil, an adjustable opening whose size is controlled by the iris. The iris, a pigmented muscle, regulates the amount of light entering the eye by contracting or dilating the pupil, thereby ensuring optimal light levels for clear vision.
Once through the pupil, the light passes through the lens, a...
Once through the pupil, the light passes through the lens, a...
01:15Depth Perception and Spatial Vision
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.
01:12Perceptual Constancy
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...
01:20Parallel Processing
The brain processes sensory information rapidly due to parallel processing, which involves sending data across multiple neural pathways at the same time. This method allows the brain to manage various sensory qualities, such as shapes, colors, movements, and locations, all concurrently. For instance, when observing a forest landscape, the brain simultaneously processes the movement of leaves, the shapes of trees, the depth between them, and the various shades of green. This enables a quick and...
01:24Vision
Vision is the result of light being detected and transduced into neural signals by the retina of the eye. This information is then further analyzed and interpreted by the brain. First, light enters the front of the eye and is focused by the cornea and lens onto the retina—a thin sheet of neural tissue lining the back of the eye. Because of refraction through the convex lens of the eye, images are projected onto the retina upside-down and reversed.
01:11Sensory Perception: Organization of the Somatosensory System
The somatosensory system is the central and peripheral nervous system component that senses and processes touch, pressure, pain, temperature, and body position or proprioception. The process of sensation takes place at three levels:
The receptor level:
The receptor level is the first stage of sensation. It involves the detection of a stimulus by specialized sensory receptors. The stimulus must arrive within the receptor's receptive field. Next, the receptor converts the energy of the stimulus...
The receptor level:
The receptor level is the first stage of sensation. It involves the detection of a stimulus by specialized sensory receptors. The stimulus must arrive within the receptor's receptive field. Next, the receptor converts the energy of the stimulus...