Related Experiment Video
Updated: Jun 26, 2026
07:37
Assessment and Communication for People with Disorders of Consciousness
Published on: August 1, 2017
What's taking so long for conscious vision?
Tarryn Balsdon1, Ljubica Jovanovic1
1Laboratoire des systèmes perceptifs, Département d'études cognitives, École normale supérieure, PSL University, Paris, France tarryn.balsdon@cnrs.fr lj.m.jovanovic@gmail.com.
The Behavioral and Brain Sciences
|June 24, 2026
Summary
Conscious vision may not require a strict 400 ms delay. Processing times vary, suggesting flexibility in how the brain integrates visual information for perception.
Area of Science:
- Cognitive Neuroscience
- Visual Perception
Background:
- A minimum processing duration of 400 milliseconds (ms) is often proposed for conscious visual perception.
- This delay is hypothesized to enable the integration of visual features processed at different rates.
Purpose of the Study:
- To investigate the necessity of a strict lower limit for the onset of conscious vision.
- To explore the flexibility in visual processing times and its implications for conscious perception.
Main Methods:
- Analysis of visual processing timelines.
- Theoretical examination of perceptual unification and intentional visual processes.
Main Results:
- Visual feature integration involves varying time constants.
- Intentional visual processes can extend beyond the proposed 400 ms limit.
Conclusions:
- The flexibility in visual processing times challenges the requirement for a rigid 400 ms lower bound for conscious vision.
- Conscious visual perception may not adhere to a strict temporal threshold.
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...
01:24Color Vision
Color perception begins in the retina, the light-sensitive layer at the back of the eye. Two main theories explain how colors are seen: the trichromatic theory and the opponent-process theory. The trichromatic theory, proposed by Thomas Young in 1802 and extended by Hermann von Helmholtz in 1852, suggests that color vision is based on three types of cone receptors in the retina. These cones are sensitive to different but overlapping ranges of wavelengths corresponding to red, blue, and green.
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.
01:20Parallel 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...
01:23Understanding Consciousness
Consciousness can be defined as the state of being aware of and able to think about one's existence, sensations, and surroundings. It encompasses two major components: awareness and arousal. Awareness pertains to the recognition of environmental stimuli and internal states. At the same time, arousal refers to the physiological readiness to engage with these stimuli, which varies significantly between states like sleep and wakefulness.
Sleep, a crucial state, is characterized by reduced physical...
Sleep, a crucial state, is characterized by reduced physical...
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...