Check out this Expanding Black Illusion. If you stare at the black shape in the middle, it will appear to expand and grow! This Expanding Black Illusion works because of a phenomenon known as lateral inhibition.
If you are interested in learning more about the Expanding Black Illusion, scroll down to read about it!
Table of Contents
- What is the Expanding Black Illusion?
- How Does the Expanding Black Illusion Work?
- Some Similar Illusions
- References and Resources
What is the Expanding Black Illusion?
The Expanding Black Illusion works because of a phenomenon known as lateral inhibition.
Lateral inhibition is a neural mechanism that occurs in the sensory systems of many organisms, including humans. It refers to the process by which neighboring sensory cells or neurons inhibit each other’s activity to enhance contrast and sharpen the perception of sensory information.
In the context of vision, lateral inhibition occurs in the retina, specifically in the network of interconnected cells known as the retina’s horizontal cells and amacrine cells. These cells play a role in processing visual information before it is transmitted to the brain.
When light enters the retina, it stimulates photoreceptor cells called rods and cones. The activated photoreceptors transmit signals to neighboring cells, including bipolar cells, which then transmit the signals to ganglion cells that form the optic nerve. However, lateral inhibition occurs before this transmission.
Horizontal cells in the retina receive input from multiple photoreceptors, while amacrine cells receive input from bipolar cells. Through lateral inhibition, these horizontal and amacrine cells inhibit the activity of neighboring cells, specifically those receiving weaker or less intense signals.
This lateral inhibition mechanism enhances the perception of contrast by suppressing the activity of cells that receive less intense stimulation while allowing cells that receive stronger stimulation to transmit their signals more effectively. This leads to an increased difference in activity levels between neighboring cells, enhancing the perception of edges and boundaries in the visual scene.
Lateral inhibition plays a crucial role in visual processing and is one of the mechanisms that contribute to our ability to perceive and distinguish fine details and contrasts in the visual world and is why the Expanding Black illusion works.
How Does the Expanding Black Illusion Work?
The Expanding Black Illusion works because of a phenomenon known as lateral inhibition.
Lateral inhibition works through a series of interactions between interconnected cells in the sensory system. Here’s a simplified explanation of how it works in the context of vision and examples like the Expanding Black Illusion:
- Photoreceptor Stimulation: When light enters the eye, it stimulates the photoreceptor cells in the retina—specifically, the rods and cones.
- Signal Transmission: Activated photoreceptor cells transmit signals to neighboring bipolar cells. Bipolar cells serve as an intermediary between the photoreceptors and ganglion cells, which send signals to the brain.
- Horizontal Cell Interaction: Horizontal cells in the retina receive input from multiple neighboring photoreceptor cells. These horizontal cells perform lateral inhibition by inhibiting the activity of neighboring cells.
- Inhibition of Weaker Signals: Horizontal cells inhibit the activity of neighboring cells that receive weaker or less intense signals. This inhibition reduces the activity of those cells, making their signal less prominent.
- Enhancement of Stronger Signals: At the same time, the inhibition of weaker signals allows cells that receive stronger stimulation to transmit their signals more effectively. This enhancement increases the contrast between neighboring cells with stronger signals.
- Output to Ganglion Cells: The bipolar cells, which have received inputs from photoreceptors and lateral inhibition from horizontal cells, transmit their modified signals to the ganglion cells.
- Perception of Contrast: The enhanced contrast between neighboring cells is transmitted to the brain via the ganglion cells, contributing to the perception of edges, boundaries, and fine details in the visual scene.
By suppressing the activity of neighboring cells with weaker signals and enhancing the activity of cells with stronger signals, lateral inhibition enhances the perception of contrast and sharpens the representation of visual information. It helps our visual system better distinguish between light and dark areas, enhancing our ability to perceive edges, textures, and fine details in the visual world.
Some Similar Illusions
The Expanding Black Illusion works because of a phenomenon known as lateral inhibition.
Lateral inhibition plays a role in various visual illusions like the the Expanding Black Illusion that exploit the contrast enhancement and edge detection mechanisms in our visual system. Here are a few examples of illusions related to lateral inhibition like the Expanding Black Illusion:
- Mach Bands: Mach bands are an optical illusion characterized by the perception of light and dark bands at the boundaries between adjacent regions of different intensities. These bands are more pronounced than the actual contrast difference, resulting from lateral inhibition enhancing the perception of contrast.
- Hermann Grid Illusion: In the Hermann grid illusion, gray dots appear at the intersections of a black grid on a white background. However, when fixating on a specific intersection, the dot seems to disappear due to lateral inhibition and the way our visual system processes the surrounding visual information.
- Simultaneous Contrast Illusion: Simultaneous contrast illusions occur when the perceived brightness or color of an object is influenced by the surrounding context. For example, placing a gray patch on a dark background makes it appear lighter, while the same gray patch on a light background appears darker. This illusion is a result of lateral inhibition amplifying the contrast between the object and its background.
- Craik-O’Brien-Cornsweet Illusion: In this illusion, a gradient of color or brightness appears to change abruptly at a boundary where there is no physical change. The perception of the boundary is enhanced due to lateral inhibition, creating a strong contrast where none actually exists.
- Mach Dichromacy Illusion: In this illusion, a figure composed of two colors appears to be monochromatic when viewed through a small aperture. Lateral inhibition and the selective processing of color information contribute to this illusion, as the brain selectively interprets the inputs from different regions.
These illusions demonstrate how lateral inhibition affects our perception of contrast, brightness, color, and boundaries in visual stimuli. By exploiting these mechanisms, these illusions challenge our perception and highlight the complex processes involved in visual processing.
References and Resources – Expanding Black Illusion
In addition to the the Expanding Black Illusion, check out our complete list of illusions
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