Filling-in, also known as Troxler’s fading, is a phenomenon in which a stationary visual stimulus eventually disappears from perception, even though it is still present in the visual field.

This occurs because the human visual system adapts to constant stimuli and eventually stops responding to them.

Table of Contents

• How does Filling In work?
• Versions of Filling In
• Illusions like Filling In
• Discovery of Filling In Fading
• References and Resources
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How does Filling In work?

Filling-in refers to the visual process by which the brain unconsciously fills in missing or degraded visual information in a scene, based on prior knowledge or expectations. This can lead to the perception of a complete and coherent image even when some parts of the visual input are missing or ambiguous. The brain uses this ability to fill-in gaps in sensory information to create a continuous and stable perception of the visual world.

Troxler’s fading and filling-in are related phenomena in vision. Troxler’s fading is a type of visual adaptation where an unchanging stimulus eventually disappears from consciousness, while filling-in refers to the brain’s ability to “fill in” the background of a visual scene based on prior knowledge or expectations. These two processes are related in that they both involve the brain unconsciously filtering out or adjusting sensory information over time.

Filling-in occurs because of the way the human visual system processes information. The visual system is constantly receiving a flood of information from the eyes, and it must filter out the most important information in order to make sense of the world. One way it does this is by adapting to constant stimuli, so that they no longer capture our attention.

When a visual stimulus is presented in the same location for a prolonged period of time, the neurons in the brain that respond to that stimulus become less responsive, and eventually stop responding altogether. This is known as neural adaptation. As a result, the stimulus disappears from perception, even though it is still present in the visual field.

In addition to neural adaptation, other mechanisms such as lateral inhibition and surround suppression also play a role in Filling-in. Lateral inhibition refers to the process by which the activation of one neuron in the visual system can inhibit the activity of neighboring neurons, which could lead to reduced perception of a stimulus. Surround suppression refers to the phenomenon where the presence of a stimulus in the surround of the fixation point can suppress perception of the stimulus at the fixation point.

Filling-in effect is not limited to visual perception, but can be observed in other senses as well, such as touch and hearing.

Versions of the Filling In

The following are some other examples of Filling in and Troxler’s Fading

Illusions like Filling In

The following are some illusions that are related to Filling In and Troxler’s Fading

The Phi phenomenon is the illusion of movement created by the rapid succession of static images or light sources.

It is the perceptual phenomenon that explains how the human brain perceives motion when presented with a sequence of still images or light sources that are displayed in rapid succession.

The Rotating Snakes is a peripheral drift illusion that consists of a grid of shapes, with some of them appearing to be rotating or undulating. The illusion is created by the interaction of the shapes with the neural processing of the visual system.

The Moiré pattern illusion: This illusion is created by superimposing two similar patterns on top of each other, such as a grid of lines or circles. The resulting pattern appears to be moving or changing.

The Scintillating Grid Illusion, in which a grid of black and white squares appears to pulsate or “breathe” when viewed from the periphery of the image.

The Hermann Grid Illusion, in which the intersections of a white grid on a black background appear to be gray, even though they are actually the same color as the background.

The Zöllner Illusion, in which parallel lines appear to be tilted or bent when intersected by diagonal lines.

The Fraser Spiral Illusion, in which a pattern of short, curved lines appears to form a spiral.

The Hering Illusion, in which two straight lines appear to be curved due to the presence of surrounding lines.

The Café Wall Illusion is a visual illusion that is created by a grid of alternating light and dark horizontal and vertical lines. The lines appear to be bent or tilted, even though they are actually straight.

These illusions are usually caused by the way our eyes process visual information and the way the brain interprets it. They can also be caused by the interaction of different visual elements, such as lines and angles, in the image. They are often used in research on visual perception and the neural basis of perception.

Discovery of Filling In Fading

The phenomenon of filling-in has been studied and documented by many vision researchers, but no single person is credited with discovering it. The concept has been developed and refined over many years by the collective efforts of many scientists in the field of vision research.

Troxler’s Fading is named after the Swiss physician and philosopher Ignaz Paul Vital Troxler, who first described it in 1804.

Ignaz Paul Vital Troxler was a Swiss physician and philosopher, born in 1780 and died in 1866. He was a physician in a Swiss hospital, and is most well-known for describing the phenomenon of Troxler’s fading, also known as Troxler’s effect, in 1804.

He first described this phenomenon in his doctoral thesis, in which he observed that a stationary visual stimulus, such as a fixed point, eventually disappears from perception even though it is still present in the visual field. He explained this phenomenon as being due to the adaptation of the retina to constant stimulus.

Troxler also made contributions to other fields, such as philosophy, psychology, and pedagogy. He published a number of papers on these subjects, and his ideas were well-received by his contemporaries.

He was also a professor at the University of Basel, where he taught anatomy and physiology.

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The Pinna Illusion is created by displaying a pattern of light and dark bars on a computer screen. The pattern appears to rotate, even though it is actually stationary.

The Pinna Illusion is similar to the Pinna-Brelstaff illusion, but it is created by the interaction between light and dark regions of the image, rather than bars.

Table of Contents

• How does the Pinna Illusion work?
• Versions of the Pinna Illusion
• Illusions like the Pinna Illusion
• Discovery of the Pinna Illusion
• References and Resources
• Sign up for emails from Mental Bomb

How does the Pinna Illusion work?

The Pinna illusion is a visual illusion that was discovered by Bruno Pinna, a cognitive scientist and researcher in the field of visual perception. The illusion is created by displaying a pattern of light and dark regions on a computer screen. The pattern appears to rotate, even though it is actually stationary.

The illusion works by exploiting the way our visual system processes information about motion. The brain uses a variety of cues, such as the relative motion of different parts of an image, to perceive motion. The Pinna illusion takes advantage of these cues by presenting an image that tricks the brain into perceiving rotation where there is none.

The illusion is created by the interaction between the light and dark regions of the image, which creates a sense of depth. The brain interprets the light and dark regions as if they were three-dimensional objects, and it uses the relative motion of the different parts of the image to perceive motion. The brain is tricked into perceiving rotation because the light and dark regions create the illusion of three-dimensional shapes that are moving relative to each other.

The Pinna illusion is one of the most powerful examples of kinetic illusions, and it is still not fully understood how it works. Some scientists have suggested that it may be related to the way the visual system processes information about the relative depth of different parts of an image, but more research is needed to fully understand the underlying mechanism of this illusion.

Version of the Pinna Illusion

The following are some alternate versions of the Pinna Illusion:

Illusions like the Pinna Illusion

Kinetic illusions are visual illusions that involve motion. They work by exploiting the way our visual system processes information about motion. The brain uses a variety of cues, such as the relative motion of different parts of an image, to perceive motion.

Kinetic illusions take advantage of these cues by presenting images in a way that tricks the brain into perceiving motion where there is none, or perceiving motion in a different direction than what is actually happening

Some similar illusions are below:

The Fraser spiral illusion is an optical illusion that is characterized by the appearance of a spiral pattern made up of concentric circles.

The rotating snakes is a peripheral drift illusion that consists of a grid of shapes, with some of them appearing to be rotating or undulating. The illusion is created by the interaction of the shapes with the neural processing of the visual system.

The Moiré pattern illusion: This illusion is created by superimposing two similar patterns on top of each other, such as a grid of lines or circles. The resulting pattern appears to be moving or changing.

The Scintillating Grid Illusion, in which a grid of black and white squares appears to pulsate or “breathe” when viewed from the periphery of the image.

The Hermann Grid Illusion in which the intersections of a white grid on a black background appear to be gray, even though they are actually the same color as the background.

The Zöllner Illusion, in which parallel lines appear to be tilted or bent when intersected by diagonal lines.

The barber pole illusion is an optical illusion that is characterized by the appearance of a spiral pattern on a vertically striped pole.

The Bezold Effect: This illusion is created by placing two or more colors next to each other, and the way they appear to change when they are close to one another.  

The Café Wall Illusion is a visual illusion that is created by a grid of alternating light and dark horizontal and vertical lines. The lines appear to be bent or tilted, even though they are actually straight.

Discovery of the Pinna Illusion

The Pinna Illusion is a visual illusion that was discovered by Bruno Pinna, a cognitive scientist and researcher in the field of visual perception.

Bruno Pinna is an Italian psychologist, known for his research in visual perception and his discovery of the Pinna illusion. He is currently a full professor of psychology at the University of Cagliari, Italy.

Pinna’s research focuses on the study of visual perception, in particular, the way in which the brain processes visual information and how it is influenced by the context of the visual environment. He is best known for his discovery of the Pinna illusion, which demonstrates the role of context and the importance of the visual cues provided by the surrounding environment in our perception of an object.

Pinna has published numerous papers on visual perception and the Pinna illusion in scientific journals, and he is considered a leading expert in the field of visual perception. He is also a member of various scientific societies and has been invited to give lectures and presentations on his research at conferences and universities around the world.

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The Pinna-Brelstaff Illusion is a visual illusion that demonstrates the role of context and the importance of the visual cues provided by the surrounding environment in our perception of an object. It is an adaptation of the original Pinna illusion.

The illusion is created by displaying a pattern of light and dark bars on a computer screen. The pattern appears to rotate, even though it is actually stationary.

Table of Contents

• How does the Pinna-Brelstaff Illusion work?
• Versions of the Pinna-Brelstaff Illusion
• Illusions like the Pinna-Brelstaff Illusion
• Discovery of the Pinna-Brelstaff Illusion
• References and Resources
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How does the Pinna-Brelstaff Illusion work?

The Pinna-Brelstaff illusion is a kinetic illusion that involves the perception of motion in a still image. It was discovered by two researchers, Bruno Pinna and Tim Brelstaff in 2001. The illusion is created by displaying a pattern of light and dark bars on a computer screen. The pattern appears to rotate, even though it is actually stationary.

The illusion is created by the interaction between the light and dark bars, which creates a sense of depth, and the way that the brain processes information about motion. The brain interprets the light and dark bars as if they were three-dimensional objects, and it uses the relative motion of the different parts of the image to perceive motion. The brain is tricked into perceiving rotation because the light and dark bars create the illusion of three-dimensional shapes that are moving relative to each other.

This illusion can be explained by the theory of “perception of relative motion” the brain relies on the relative motion of the parts of an image to perceive motion. The light and dark bars creates the illusion of 3D shapes that are moving relative to each other, this creates the perception of rotation.

Version of the Pinna-Brelstaff Illusion

The following are some alternate versions of the Pinna-Brelstaff Illusion:

Illusions like the Pinna-Brelstaff Illusion

Kinetic illusions are visual illusions that involve motion. They work by exploiting the way our visual system processes information about motion. The brain uses a variety of cues, such as the relative motion of different parts of an image, to perceive motion.

Kinetic illusions take advantage of these cues by presenting images in a way that tricks the brain into perceiving motion where there is none, or perceiving motion in a different direction than what is actually happening

Some similar illusions are below:

The Fraser spiral illusion is an optical illusion that is characterized by the appearance of a spiral pattern made up of concentric circles.

The rotating snakes is a peripheral drift illusion that consists of a grid of shapes, with some of them appearing to be rotating or undulating. The illusion is created by the interaction of the shapes with the neural processing of the visual system.

The Moiré pattern illusion: This illusion is created by superimposing two similar patterns on top of each other, such as a grid of lines or circles. The resulting pattern appears to be moving or changing.

The Scintillating Grid Illusion, in which a grid of black and white squares appears to pulsate or “breathe” when viewed from the periphery of the image.

The Hermann Grid Illusion in which the intersections of a white grid on a black background appear to be gray, even though they are actually the same color as the background.

The Zöllner Illusion, in which parallel lines appear to be tilted or bent when intersected by diagonal lines.

The barber pole illusion is an optical illusion that is characterized by the appearance of a spiral pattern on a vertically striped pole.

The Bezold Effect: This illusion is created by placing two or more colors next to each other, and the way they appear to change when they are close to one another.  

The Café Wall Illusion is a visual illusion that is created by a grid of alternating light and dark horizontal and vertical lines. The lines appear to be bent or tilted, even though they are actually straight.

Discovery of the Pinna-Brelstaff Illusion

It was discovered by two researchers, Bruno Pinna and Tim Brelstaff in 2001.

Bruno Pinna is an Italian psychologist, known for his research in visual perception and his discovery of the Pinna illusion. He is currently a full professor of psychology at the University of Cagliari, Italy.

Pinna’s research focuses on the study of visual perception, in particular, the way in which the brain processes visual information and how it is influenced by the context of the visual environment. He is best known for his discovery of the Pinna illusion, which demonstrates the role of context and the importance of the visual cues provided by the surrounding environment in our perception of an object.

Pinna has published numerous papers on visual perception and the Pinna illusion in scientific journals, and he is considered a leading expert in the field of visual perception. He is also a member of various scientific societies and has been invited to give lectures and presentations on his research at conferences and universities around the world.

References and Resources

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Persistence of vision is the phenomenon by which the brain continues to perceive an image even after the image is no longer present.

This occurs because the cells in the retina, called rods and cones, take a brief period of time to “reset” after being stimulated.

As a result, when an image is removed, these cells continue to send signals to the brain for a short period of time, creating the illusion that the image is still present.

Persistence of vision is the scientific explanation behind the afterimage illusion, as well as the illusion of motion in moving pictures such as films and animations.

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• How does the Persistence of Vision work?
• Versions of the Persistence of Vision
• Illusions like the Persistence of Vision
• Discovery of the Persistence of Vision
• References and Resources
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How does the Persistence of Vision work?

Persistence of vision works by the way our eyes and brain process visual information. When light enters our eyes, it is absorbed by cells in the retina called rods and cones. These cells then send electrical signals to the brain, which interprets these signals as visual information. The brain is able to process images very quickly, and can hold onto an image for a brief period of time even after it is no longer present. This is known as the “persistence of vision.”

When we watch a movie or animation, for example, the images are presented to us in rapid succession. The brain combines these images and interprets them as a single, continuous image, creating the illusion of motion. This is due to persistence of vision.

Similarly, when we see a light being turned on and off quickly, the brain combines these images and interprets them as a single, continuous light. This is also due to persistence of vision.

Persistence of vision also plays a role in other visual phenomena, such as afterimages, optical illusions and other types of illusions, as well as in some cases of visual hallucinations.

It’s worth noting that persistence of vision is not a unique property of human vision, many animals have this ability as well.

Versions of the Persistence of Vision

There are many examples of persistence of vision in everyday life. Some of these include:

Moving pictures: When we watch films or animations, the rapid succession of still images creates the illusion of motion. This is due to persistence of vision.

Flickering lights: When we see a light being turned on and off quickly, it can create the illusion of a continuous glow. This is also due to persistence of vision.

Spin art: When a spinning object is decorated with different colors, the colors appear to blend together and create new colors. This is due to persistence of vision.

Fireworks: The bright trails left by fireworks are caused by persistence of vision, as the brain continues to see the light even after the firework has exploded.

Afterimages: When we look at a bright light, or an image for an extended period of time, and then look away, we can see an afterimage of that image or light. This is also caused by persistence of vision.

The following are some other examples of Persistence of Vision

Illusions like Persistence of Vision

Some related illusions include the following:

Afterimage Illusion

The afterimage illusion is a type of visual illusion in which an image continues to appear in the observer’s visual field after the original stimulus has been removed.

The Checker Shadow Illusion is created by a checkerboard pattern composed of squares with different luminance values, the squares that are not directly illuminated by the light source appear darker than the illuminated squares, creating the illusion of shadows.

The simultaneous contrast illusion is a visual effect that occurs when the perception of a color is affected by the colors of the surrounding area.

The illusion creates the appearance of a change in the color of an object, even though the actual color of the object remains constant.

The Neon Color Spreading illusion refers to the visual phenomenon where an area of color appears to spread or “bleed” beyond its intended boundaries.

The Bezold Effect: This illusion is created by placing two or more colors next to each other, and the way they appear to change when they are close to one another.  

The Cornsweet illusion is a classic example of a brightness illusion, which is an illusion in which two areas that are physically the same brightness appear to be different in brightness.

The Chubb illusion is based on the perception of brightness and can be observed when a small bright patch is surrounded by a larger dark area, the small bright patch will appear brighter than the same patch surrounded by a bright area.

The Watercolor Illusion: This illusion is created by the way the brain perceives edges of an object. When an object is surrounded by a colored halo, the object appears to have a different color than it actually does.

The Café Wall Illusion is a visual illusion that is created by a grid of alternating light and dark horizontal and vertical lines. The lines appear to be bent or tilted, even though they are actually straight.

Discovery of the Persistence of Vision

The phenomenon of persistence of vision, has been known for centuries.

The ancient Greeks and Romans were aware of the phenomenon, and it was also described by the ancient Chinese and Arab scholars.

The earliest scientific study of afterimages was done by the German scientist Hermann von Helmholtz in the 19th century.

He published a book in 1867 titled “Handbook of Physiological Optics” which gave a detailed explanation of the phenomenon, including the theory that afterimages were caused by the retina’s sensitivity to light.

This study is considered as one of the earliest and most comprehensive explanations of the effect.

References and Resources

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