Geometric Illusions

The Vertical–Horizontal illusion, also known as the T illusion, is a visual perception illusion that involves a T-shaped figure with a horizontal bar and a vertical bar. The brain perceives the vertical bar as being longer than the horizontal bar, even though they are the same length.

Table of Contents

• How does the Vertical–Horizontal Illusion work?
• Versions of the Vertical–Horizontal Illusion
• Illusions like the Vertical–Horizontal Illusion
• Discovery of the Vertical–Horizontal Illusion
• Gender and Cultural Differences
• References and Resources
• Sign up for emails from Mental Bomb

How does the Vertical–Horizontal Illusion work?

The T-illusion works by exploiting the brain’s tendency to interpret visual information in the context of other visual information. The brain uses various cues, such as angles and lines, to infer the three-dimensional structure of an object and the context in which it is presented. In the case of the T-illusion, the brain interprets the vertical bar as being farther away than the horizontal bar.

The brain uses the concept of linear perspective, which is the way that parallel lines appear to converge as they extend into the distance. The brain expects that the lines that are farther away should appear to be closer together than the lines that are closer. In the T-illusion, the vertical bar is interpreted as a continuation of the horizontal bar and the brain perceives it as farther away, which leads to the perception that the vertical bar is longer than the horizontal bar.

This illusion is also thought to be related to the concept of “Gestalt grouping” which is the way the brain organizes different elements in a scene into groups based on certain rules such as proximity, similarity, and continuity. The horizontal and vertical lines in the T-illusion create a sense of continuation and proximity between the lines which leads to the perception of the vertical line as a continuation of the horizontal line, making it appear longer.

In summary, the T-illusion works by the brain’s interpretation of visual information in the context of other visual information, the concept of linear perspective, and the Gestalt grouping rules. The brain uses these cues to perceive the lines as if they were in different distances and therefore different sizes.

Versions of the Vertical–Horizontal Illusion

The following are some alternate versions of the Vertical–Horizontal Illusion:

Illusions like the Vertical–Horizontal Illusion

The Poggendorff illusion: This illusion is similar to the Müller-Lyer illusion, but instead of arrowheads, it uses a diagonal line that intersects two parallel lines. The brain perceives the diagonal line as being tilted, causing the parallel lines to appear as if they are not parallel.

The Ebbinghaus illusion: This illusion involves circles of different sizes, but with the same-sized circles placed close to each other. The brain perceives the smaller circles as being larger when they are placed next to larger circles.

The Müller-Lyer illusion is a visual perception illusion that consists of two lines of equal length, with arrows at each end pointing either inward or outward. The line with the inward-pointing arrows appears shorter than the line with the outward-pointing arrows, even though they are actually the same length. 

The Kanizsa triangle: This illusion is created by placing Pac-Man-like shapes around an invisible triangle. The brain perceives the triangle as if it were a real, visible triangle.

The Zöllner illusion: This illusion involves parallel lines with diagonal lines intersecting them. The brain perceives the lines as if they were not parallel and that the diagonal lines are converging.

Moon illusion: This illusion involves the perception of the Moon appearing larger when it is near the horizon compared to when it is high in the sky.

Ponzo illusion: This illusion involves the perception of an object appearing larger or smaller depending on the size of the surrounding context.

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.

All these illusions are based on the brain’s perception of visual context, depth cues, and grouping rules. These illusions help to understand how the brain interprets visual information and how it can be deceived.

Discovery of the Vertical–Horizontal Illusion

In 1858 Wilhelm Wundt introduced the horizontal-vertical illusion.

Wilhelm Wundt (1832-1920) was a German physician, physiologist, and philosopher. He is considered to be one of the founders of modern psychology and is often referred to as the “father of experimental psychology.” He is credited with establishing the first psychology laboratory in 1879 at the University of Leipzig in Germany, where he conducted research on the nature of mental processes and the relationship between the mind and the body.

Wundt’s work laid the foundation for the development of scientific psychology as a separate discipline. He believed that psychology should be studied using methods and techniques from the natural sciences, and he developed a number of experimental techniques to study mental processes such as sensation, perception, and attention. He also developed the concept of “introspection,” which is the process of self-observation and self-examination of one’s own mental states.

Wundt’s work had a major influence on the development of the field of psychology and his ideas continue to be studied and debated today. He is considered one of the most influential figures in the history of psychology and his legacy is still felt in the field today.

Wundt died in 1920 in Großbothen, Germany. He has written many books and articles on the topic of psychology, his most famous being “Principles of Physiological Psychology” which is considered as a cornerstone in the field of psychology.

Gender Differences with the Vertical–Horizontal Illusion

There is some research that suggests that there may be gender differences in the perception of the T-illusion. Some studies have found that men tend to perceive the vertical bar as longer than the horizontal bar more than women do. Other studies have found that women tend to perceive the horizontal bar as longer than the vertical bar more than men do.

There are a few possible explanations for these gender differences in the perception of the T-illusion. One possibility is that there may be differences in the way that men and women process visual information. For example, men may be more likely to rely on visual cues related to depth and distance, while women may be more likely to rely on cues related to shape and form.

Another possibility is that the gender differences in the perception of the T-illusion may be due to cultural or societal factors. Men and women may be exposed to different types of visual information and may have different experiences that affect their perception of the illusion.

It’s important to note that these gender differences in the perception of the T-illusion are not conclusive and more research is needed to understand the underlying cause and nature of these differences.

It’s also worth noting that despite any potential difference, the T-illusion is still a visual perception illusion that works by exploiting the brain’s tendency to interpret visual information in the context of other visual information and it’s an important tool for researchers to better understand how the brain process visual information.

Cultural Differences with the Vertical–Horizontal Illusion

There is some research that suggests that there may be cultural differences in the perception of the T-illusion. Some studies have found that people from different cultures perceive the T-illusion differently. For example, a study found that Westerners tend to perceive the vertical bar as longer than the horizontal bar, while people from some non-Western cultures tend to perceive the horizontal bar as longer than the vertical bar.

The explanations for these cultural differences in the perception of the T-illusion are not clear and there are multiple hypotheses, one of them is that cultural differences in visual perception may be related to differences in the way that people from different cultures process visual information. For example, people from Western cultures may be more likely to rely on visual cues related to depth and distance, while people from some non-Western cultures may be more likely to rely on cues related to shape and form.

Another explanation is related to the cultural context and the type of visual information people are exposed to, which may influence how they perceive visual information. For example, cultures that rely more on oral storytelling may be less affected by the illusion than cultures where visual representation is more prevalent.

It’s also possible that these cultural differences in the perception of the T-illusion may be due to other factors such as education, socioeconomic status, and exposure to different types of visual information.

It’s important to note that these cultural differences in the perception of the T-illusion are not conclusive, and more research is needed to understand the underlying causes and nature of these differences.

It’s also worth noting that despite any potential difference, the T-illusion is still a visual perception illusion that works by exploiting the brain’s tendency to interpret visual information in the context of other visual information and it’s an important tool for researchers to better understand how the brain processes visual information.

References and Resources

Check out our complete list of illusions.

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The T illusion, also known as the Vertical–horizontal illusion, is a visual perception illusion that involves a T-shaped figure with a horizontal bar and a vertical bar. The brain perceives the vertical bar as being longer than the horizontal bar, even though they are the same length.

Table of Contents

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

How does the T Illusion work?

The T-illusion works by exploiting the brain’s tendency to interpret visual information in the context of other visual information. The brain uses various cues, such as angles and lines, to infer the three-dimensional structure of an object and the context in which it is presented. In the case of the T-illusion, the brain interprets the vertical bar as being farther away than the horizontal bar.

The brain uses the concept of linear perspective, which is the way that parallel lines appear to converge as they extend into the distance. The brain expects that the lines that are farther away should appear to be closer together than the lines that are closer. In the T-illusion, the vertical bar is interpreted as a continuation of the horizontal bar and the brain perceives it as farther away, which leads to the perception that the vertical bar is longer than the horizontal bar.

This illusion is also thought to be related to the concept of “Gestalt grouping” which is the way the brain organizes different elements in a scene into groups based on certain rules such as proximity, similarity, and continuity. The horizontal and vertical lines in the T-illusion create a sense of continuation and proximity between the lines which leads to the perception of the vertical line as a continuation of the horizontal line, making it appear longer.

In summary, the T-illusion works by the brain’s interpretation of visual information in the context of other visual information, the concept of linear perspective, and the Gestalt grouping rules. The brain uses these cues to perceive the lines as if they were in different distances and therefore different sizes.

Versions of the T Illusion

The following are some alternate versions of the T Illusion:

Illusions like the T Illusion

The Poggendorff illusion: This illusion is similar to the Müller-Lyer illusion, but instead of arrowheads, it uses a diagonal line that intersects two parallel lines. The brain perceives the diagonal line as being tilted, causing the parallel lines to appear as if they are not parallel.

The Ebbinghaus illusion: This illusion involves circles of different sizes, but with the same-sized circles placed close to each other. The brain perceives the smaller circles as being larger when they are placed next to larger circles.

The Müller-Lyer illusion is a visual perception illusion that consists of two lines of equal length, with arrows at each end pointing either inward or outward. The line with the inward-pointing arrows appears shorter than the line with the outward-pointing arrows, even though they are actually the same length. 

The Kanizsa triangle: This illusion is created by placing Pac-Man-like shapes around an invisible triangle. The brain perceives the triangle as if it were a real, visible triangle.

The Zöllner illusion: This illusion involves parallel lines with diagonal lines intersecting them. The brain perceives the lines as if they were not parallel and that the diagonal lines are converging.

Moon illusion: This illusion involves the perception of the Moon appearing larger when it is near the horizon compared to when it is high in the sky.

Ponzo illusion: This illusion involves the perception of an object appearing larger or smaller depending on the size of the surrounding context.

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.

All these illusions are based on the brain’s perception of visual context, depth cues, and grouping rules. These illusions help to understand how the brain interprets visual information and how it can be deceived.

Discovery of the T Illusion

In 1858 Wilhelm Wundt introduced the horizontal-vertical illusion.

Wilhelm Wundt (1832-1920) was a German physician, physiologist, and philosopher. He is considered to be one of the founders of modern psychology and is often referred to as the “father of experimental psychology.” He is credited with establishing the first psychology laboratory in 1879 at the University of Leipzig in Germany, where he conducted research on the nature of mental processes and the relationship between the mind and the body.

Wundt’s work laid the foundation for the development of scientific psychology as a separate discipline. He believed that psychology should be studied using methods and techniques from the natural sciences, and he developed a number of experimental techniques to study mental processes such as sensation, perception, and attention. He also developed the concept of “introspection,” which is the process of self-observation and self-examination of one’s own mental states.

Wundt’s work had a major influence on the development of the field of psychology and his ideas continue to be studied and debated today. He is considered one of the most influential figures in the history of psychology and his legacy is still felt in the field today.

Wundt died in 1920 in Großbothen, Germany. He has written many books and articles on the topic of psychology, his most famous being “Principles of Physiological Psychology” which is considered as a cornerstone in the field of psychology.

Gender Differences with the T Illusion

There is some research that suggests that there may be gender differences in the perception of the T-illusion. Some studies have found that men tend to perceive the vertical bar as longer than the horizontal bar more than women do. Other studies have found that women tend to perceive the horizontal bar as longer than the vertical bar more than men do.

There are a few possible explanations for these gender differences in the perception of the T-illusion. One possibility is that there may be differences in the way that men and women process visual information. For example, men may be more likely to rely on visual cues related to depth and distance, while women may be more likely to rely on cues related to shape and form.

Another possibility is that the gender differences in the perception of the T-illusion may be due to cultural or societal factors. Men and women may be exposed to different types of visual information and may have different experiences that affect their perception of the illusion.

It’s important to note that these gender differences in the perception of the T-illusion are not conclusive and more research is needed to understand the underlying cause and nature of these differences.

It’s also worth noting that despite any potential difference, the T-illusion is still a visual perception illusion that works by exploiting the brain’s tendency to interpret visual information in the context of other visual information and it’s an important tool for researchers to better understand how the brain process visual information.

Cultural Differences with the T Illusion

There is some research that suggests that there may be cultural differences in the perception of the T-illusion. Some studies have found that people from different cultures perceive the T-illusion differently. For example, a study found that Westerners tend to perceive the vertical bar as longer than the horizontal bar, while people from some non-Western cultures tend to perceive the horizontal bar as longer than the vertical bar.

The explanations for these cultural differences in the perception of the T-illusion are not clear and there are multiple hypotheses, one of them is that cultural differences in visual perception may be related to differences in the way that people from different cultures process visual information. For example, people from Western cultures may be more likely to rely on visual cues related to depth and distance, while people from some non-Western cultures may be more likely to rely on cues related to shape and form.

Another explanation is related to the cultural context and the type of visual information people are exposed to, which may influence how they perceive visual information. For example, cultures that rely more on oral storytelling may be less affected by the illusion than cultures where visual representation is more prevalent.

It’s also possible that these cultural differences in the perception of the T-illusion may be due to other factors such as education, socioeconomic status, and exposure to different types of visual information.

It’s important to note that these cultural differences in the perception of the T-illusion are not conclusive, and more research is needed to understand the underlying causes and nature of these differences.

It’s also worth noting that despite any potential difference, the T-illusion is still a visual perception illusion that works by exploiting the brain’s tendency to interpret visual information in the context of other visual information and it’s an important tool for researchers to better understand how the brain processes visual information.

References and Resources

Check out our complete list of illusions.

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The Hering illusion is a visual illusion that involves the perception of curved lines as being bowed inwards or outwards. In the illusion, the red lines appear to curve. In realty, the red lines are perfectly straight.

Table of Contents

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

How does the Hering Illusion work?

The Hering illusion is a visual illusion that involves the perception of curved lines as being bowed inwards or outwards. The illusion is named after the German physiologist Ewald Hering, who first described it in 1861. The illusion is often used to study the perception of depth and the role of the visual system in shaping our perception of the world.

The illusion is created by placing a series of parallel lines in the form of a rectangle, with the lines on one side of the rectangle being closer together than the lines on the other side. This creates the illusion that the lines on one side of the rectangle are bowed inwards, while the lines on the other side appear to be bowed outwards.

The perception of the illusion is thought to be caused by the brain’s tendency to perceive the lines as being farther away or closer based on their spacing. The lines that are closer together are perceived as being farther away, while the lines that are farther apart are perceived as being closer. This leads to the perception of the lines as curved, when in reality they are straight.

The Hering illusion is used to demonstrate the role that context and surrounding plays in shaping our perception of reality. It also highlights how the brain uses depth cues such as relative size, distance, and position to perceive the 3D world around us.

Versions of the Hering Illusion

The following are some alternate versions of the Hering Illusion:

Illusions like the Hering Illusion

The following are some illusions similar to the Hering Illusion.

The Zöllner illusion is a visual illusion in which parallel lines appear to be angled due to the presence of intersecting lines.

The illusion is often used to study the brain’s perception of shape and spatial relationships. It is considered one of the most powerful and striking examples of a geometrical-optical illusion. The perception of the illusion can be explained by the brain’s tendency to group lines together based on their similarity in direction and spacing, which can lead to an overestimation of the angle between the parallel lines.

The Müller-Lyer illusion: This illusion involves lines with arrowheads at the ends, which can make a line appear longer or shorter depending on the direction of the arrowheads.

The Poggendorff illusion is a visual illusion in which the brain perceives a diagonal line as being interrupted by an object, even though the line is actually continuous. The illusion is created by the misalignment of two parallel lines that are intersected by a third line at a certain angle.

The Orbison illusion is an illusion of movement that is created when stationary, parallel lines are placed on a background of radiating lines. The parallel lines appear to be moving in the direction of the radiating lines, even though they are actually stationary. This illusion is thought to be caused by the interaction between the parallel lines and the radiating lines, which creates an illusion of movement in the brain.

The Wundt illusion is an optical illusion produces an inversed effect compared to the Hering Illusion. The vertical lines are both straight, but they may look as if they are curved inwards.

Discovery of the Hering Illusion

The illusion is named after the German physiologist Ewald Hering, who first described it in 1861.

Ewald Hering was a German physiologist and psychologist who lived in the 19th and early 20th centuries. He is best known for his research on perception and visual illusions, particularly the Hering illusion, which is named after him.

Hering’s work in perception focused on the process of color vision and binocular depth perception, and he proposed several theories to explain these phenomena. He also made important contributions to the study of visual illusions, and was one of the first researchers to systematically study the factors that influence the perception of depth and distance.

In addition to his research, Hering was also an influential teacher and mentor to many other researchers in the field of perception and vision. He held positions at several universities in Germany, including the University of Berlin and the University of Würzburg, where he trained many students who went on to make their own contributions to the field.

References and Resources

Check out our complete list of illusions.

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The Delboeuf illusion is a perceptual illusion in which the perceived size of a circle is affected by the size of the surrounding circles.

In the illusion, a central circle surrounded by larger circles appears smaller than the same central circle surrounded by smaller circles, even though the central circle is identical in both cases. The illusion demonstrates that the perceived size of an object can be influenced by the context in which it is presented.

Table of Contents

• How does the Delboeuf Illusion work?
• Versions of the Delboeuf Illusion
• Illusions like the Delboeuf Illusion
• Discovery of the Delboeuf Illusion
• Impact of the Delboeuf Illusion on the Food Industry
• References and Resources
• Sign up for emails from Mental Bomb

How does the Delboeuf Illusion work?

The Delboeuf illusion works by altering the perceived relative size of the central circle compared to the surrounding circles. The brain uses the size of the surrounding circles as a reference point to judge the size of the central circle. When the surrounding circles are larger, the central circle appears smaller in comparison, and when the surrounding circles are smaller, the central circle appears larger.

This illusion is thought to be caused by a process in the brain called “size constancy scaling.” This process allows the brain to adjust for the size of an object relative to its surroundings. In the Delboeuf illusion, the brain incorrectly adjusts the perceived size of the central circle based on the size of the surrounding circles.

It’s also thought that the Delboeuf illusion is caused by the way the brain processes the spatial relationships between objects. The brain uses distance and angle as cues to determine the size of an object, and these cues can be influenced by the presence of surrounding objects. In the case of the Delboeuf illusion, the brain may interpret the larger surrounding circles as being closer to the central circle, making the central circle appear smaller.

It’s important to note that the Delboeuf illusion is not limited to circles, it works also with other shapes and sizes, it’s a general principle that applies to all types of stimuli.

Versions of the Delboeuf Illusion

The following are some versions of the Delbouf Illusion

Illusions like the Delboeuf Illusion

The Delboeuf Illusion is a size constancy illusions in which the perceived size of an object is affected by its surroundings. Some examples of size constancy illusions include:

The Ebbinghaus illusion: This illusion is similar to the Delboeuf illusion but in this case the central circle appears larger when surrounded by smaller circles and smaller when surrounded by larger circles.

The Occlusion illusion is a visual illusion where an object that is partially obscured by another object appears to be farther away than it actually is. This illusion is caused by the brain’s interpretation of the relative depth of the objects based on their relative size and position. This phenomenon is based on the visual cues that the brain uses to perceive depth, such as relative size, position, and overlap.

The Müller-Lyer illusion is a classic example of size-contrast illusion, in which two lines of equal length appear to be different due to the presence of arrowheads or fins at the end of the lines.

Moon illusion: This illusion involves the perception of the Moon appearing larger when it is near the horizon compared to when it is high in the sky.

Ponzo illusion: This illusion involves the perception of an object appearing larger or smaller depending on the size of the surrounding context.

All these illusions demonstrate that the perceived size of an object can be influenced by the context in which it is presented, and that the brain uses the size of the surrounding objects as a reference point to judge the size of the central object.

Discovery of the Delboeuf Illusion

The illusion is named after the Belgian psychologist Joseph Delboeuf, who first described it in 1865.

Joseph Remi Leopold Delboeuf (1831-1896) was a Belgian psychologist and philosopher who is best known for his work on the Delboeuf illusion, a perceptual illusion in which the perceived size of a circle is affected by the size of the surrounding circles. Delboeuf was one of the early pioneers of experimental psychology, and his work on the Delboeuf illusion was an important contribution to our understanding of how the brain processes visual information.

Delboeuf was born in Brussels, Belgium in 1831. He studied mathematics, physics and chemistry at the University of Brussels and later received a degree in medicine. He then studied philosophy and psychology at the Universities of Leipzig and Berlin. After completing his education, he returned to Brussels and became a professor of psychology at the University of Brussels. He also founded the Belgian Society for Psychology.

Delboeuf’s work on the Delboeuf illusion was published in 1865, in which he presented the illusion and demonstrated that the perceived size of an object can be influenced by the context in which it is presented. His work in this area was important in showing that visual perception is not just a passive process, but that the brain actively interprets the information it receives. He also made other contributions to the field of psychology, he studied the perception of time, and he wrote on the philosophy of psychology.

Delboeuf died in 1896 in Brussels, Belgium. His legacy in psychology is still being studied and cited today.

Impact of the Delboeuf Illusion in the Food Industry

The Delboeuf illusion impacts the food industry in a few ways.

First, the illusion can be used to make food portions appear larger or smaller than they actually are. For example, using smaller plates or bowls can make a small portion of food appear larger, while using larger plates or bowls can make a large portion of food appear smaller. This can be used to create the illusion of value for customers, or to make healthier portion sizes appear more satisfying.

Second, the Delboeuf illusion can be used in food packaging design. For example, using larger or smaller images of food on packaging can make the contents of the package appear larger or smaller than they actually are. This can be used to make smaller products appear more appealing or to make larger products appear more economical.

Third, the Delboeuf illusion can be used in restaurant settings. For example, using smaller plates or glasses can make small servings of food or drink appear larger, while using larger plates or glasses can make larger servings appear smaller. This can be used to influence customer perceptions of value and satisfaction.

It’s important to note that in the food industry, manipulating the Delboeuf illusion can be considered as a form of deceptive marketing, and in some countries, it is regulated by law. It’s important to be transparent and honest with the customers and to follow the laws.

References and Resources

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The Poggendorff illusion is a visual illusion in which the brain perceives a diagonal line as being interrupted by an object, even though the line is actually continuous.

The illusion is created by the misalignment of two parallel lines that are intersected by a third line at a certain angle.

In the version below, a straight black and red line is covered by grey rectangle. However, the blue line, not red line, appears to be an extension of the black line. The image on the right reveals the truth.

Table of Contents

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

How does the Poggendorff Illusion work?

The Poggendorff illusion works by the brain interpreting the misalignment of two parallel lines that are intersected by a third line at a certain angle as a gap or interruption in the diagonal line, even though the line is actually continuous. It is thought that the brain interprets the misalignment as an occlusion, or an object blocking the diagonal line, which causes the illusion.

The exact neural mechanisms that underlie the Poggendorff illusion are not well understood, but it is thought that the brain’s tendency to group similar elements together, known as gestalt grouping, plays a role. Additionally, the brain’s tendency to perceive lines and edges as continuing behind occluding objects may also contribute to the illusion.

Overall, the Poggendorff illusion demonstrate that visual perception is an active process that is influenced by both the physical properties of the stimulus and the brain’s assumptions about the scene.

The illusion was first described by the German physicist Johann Poggendorff in 1860. It is often used in research on perception and cognitive psychology to study the way the brain processes visual information.

Versions of the Poggendorff Illusion

The following are some alternate versions of the Poggendorff Illusion

Illusions like the Poggendorff Illusion

The Poggendorff illusion is a type of size-distance illusions, also known as size contrast illusions, which are visual illusions in which the size or distance of an object is perceived differently than it actually is. These illusions are caused by the way the brain processes visual information and the surrounding context. Some examples of size-distance illusions include:

The Ebbinghaus illusion (also known as Titchener circles) is a perceptual illusion in which the perceived size of a central circle is affected by the size of the surrounding circles. The central circle appears smaller when surrounded by larger circles, and larger when surrounded by smaller circles.

The Delboeuf Illusion: This illusion involves the perception of circles of different sizes appearing to be the same size when they are surrounded by other circles of different sizes.

The Zöllner illusion: A another size-contrast illusion in which a group of diagonal lines appear to be distorted or bent due to the presence of intersecting lines. This illusion involves the perception of diagonal lines that appear to be bent or tilted, even though they are actually straight.

The Müller-Lyer illusion is a classic example of size-contrast illusion, in which two lines of equal length appear to be different due to the presence of arrowheads or fins at the end of the lines.

Moon illusion: This illusion involves the perception of the Moon appearing larger when it is near the horizon compared to when it is high in the sky.

Ponzo illusion: This illusion involves the perception of an object appearing larger or smaller depending on the size of the surrounding context.

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.

Münsterberg illusion: A special version of the Café Wall Illusion. This illusion involving the perception of the size of an object appearing to change when the surrounding context changes.

These illusions show that the brain’s perception of size and distance can be influenced by the surrounding context, and that the visual information the brain receives is not always an accurate representation of reality.

Discovery of the Poggendorff Illusion

The illusion was first described by the German physicist Johann Poggendorff in 1860. It is often used in research on perception and cognitive psychology to study the way the brain processes visual information.

Johann Christian Poggendorff was a German physicist, mathematician and inventor. He is best known for his work in the field of electricity and magnetism, and for his invention of the Poggendorff Illusion. He was born in 1796 in Hamburg, Germany and died in 1877 in Berlin, Germany.

Poggendorff studied mathematics and physics at the University of Berlin and later worked as a professor of physics at the University of Breslau. He made significant contributions to the field of electricity and magnetism, including the invention of the Poggendorff Illusion in 1860. He also developed the Poggendorff’s circle, a mathematical construct used to represent the intersection of two circles in a plane.

Poggendorff was also a member of several scientific societies and was awarded several honors for his work, including the Copley Medal of the Royal Society of London in 1878. He is also remembered for his contributions to the field of science through the Poggendorff’s Annalen der Physik und Chemie, which he founded and edited for many years.

References and Resources

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The Ebbinghaus illusion (also known as Titchener circles) is a perceptual illusion in which the perceived size of a central circle is affected by the size of the surrounding circles. The central circle appears smaller when surrounded by larger circles, and larger when surrounded by smaller circles.

Table of Contents

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

How does the Ebbinghaus Illusion work?

The Ebbinghaus illusion works by exploiting the way our brain processes visual information. Our brain is constantly trying to make sense of the visual information it receives by making comparisons and judgments about the size, shape, and position of objects in our environment. In the case of the Ebbinghaus illusion, the brain is making a comparison between the size of the central circle and the size of the surrounding circles.

When the surrounding circles are larger than the central circle, our brain perceives them as being farther away and thus the central circle appears smaller in comparison. When the surrounding circles are smaller than the central circle, our brain perceives them as being closer and the central circle appears larger in comparison.

Additionally, the brain also takes into account the proximity of the surrounding circles to the central circle. So, if the surrounding circles are placed in close proximity to the central circle, it will appear smaller than when they are placed farther away.

This illusion is thought to be caused by a neural mechanism in the brain called contextual modulation, which modifies the visual perception of an object based on the context in which it is presented. The Ebbinghaus illusion is a classic example of how context can affect perception and highlights the complex nature of visual processing in the brain.

Versions of the Ebbinghaus Illusion

The following are some alternate versions of the Ebbinghaus Illusion

Illusions like the Ebbinghaus Illusion

The Ebbinghaus illusion is a type of size-contrast illusion. A size-contrast illusion is a type of visual illusion in which the perceived size of an object is affected by the size of the surrounding objects. The Ebbinghaus illusion specifically is related to relative size, where the perception of the size of the central circle changes depending on the size of the surrounding circles. Size-contrast illusions occur due to the way that the visual system processes relative size information in a scene, and the Ebbinghaus illusion is a classic example of this type of illusion.

There are many other examples of size-contrast illusions in addition to the Ebbinghaus illusion. Here are a few examples:

The Delboeuf illusion is similar to the Ebbinghaus illusion, but instead of circles, it uses two concentric circles or rings. The central ring appears larger or smaller depending on the size of the surrounding ring.

The Poggendorff illusion is another size-contrast illusion in which a straight line appears to be bent or angled, due to the presence of intersecting lines or shapes in the background.

The Zöllner illusion is another size-contrast illusion in which a group of diagonal lines appear to be distorted or bent due to the presence of intersecting lines.

The Müller-Lyer illusion is a classic example of size-contrast illusion, in which two lines of equal length appear to be different due to the presence of arrowheads or fins at the end of the lines.

All of these illusions rely on the way the visual system processes relative size information, and they all highlight the complexity and malleability of visual perception.

Discovery of the Ebbinghaus Illusion

This illusion is named after German psychologist Hermann Ebbinghaus, who first described it in the late 19th century. The illusion is thought to be caused by the way the brain processes relative size information in visual scenes.

Hermann Ebbinghaus (1850-1909) was a German psychologist who is best known for his pioneering research on memory and forgetting. He was one of the first researchers to systematically study memory as a psychological process and his work laid the foundation for the field of experimental psychology. Ebbinghaus conducted a series of experiments in which he memorized lists of nonsense syllables and then tested his own memory at various intervals to measure the rate of forgetting.

He also developed the first standardized memory test, called the “memory drum”, which consisted of a rotating drum with lists of words or syllables that could be presented to participants at different intervals. He used these tests to study the effects of different factors, such as repetition and interference, on memory retention.

Ebbinghaus also made significant contributions to the understanding of memory processes, such as the spacing effect, which states that spaced practice is more effective than massed practice in enhancing memory retention.

Ebbinghaus’s work was groundbreaking in the field of psychology and is still widely cited today. The Ebbinghaus illusion, the size-contrast illusion that bears his name, was discovered by him in 1885 but is not as well-known as his memory research.

References and Resources

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