The Kanizsa triangle is a visual illusion that was first described by the Italian psychologist Gaetano Kanizsa in 1955. The illusion consists of a white equilateral triangle that appears to be surrounded by three Pac-Man-like shapes, which are black and have white crescents facing inwards.
The three Pac-Man-like shapes are actually made up of three partially-overlapping circles with white edges that create the illusion of a triangle.
The Kanizsa triangle is an example of an “amodal completion” illusion, in which the brain fills in missing information to complete an object or shape. In this case, the brain completes the triangle by connecting the three white crescents of the circles together. The illusion is thought to occur because the brain is wired to perceive objects as whole and complete, even when they are not fully present in the visual field.
Table of Contents
- How does the Kanizsa Triangle work?
- Versions of the Kanizsa Triangle Illusion
- Illusions like the Kanizsa Triangle
- Discovery of the Kanizsa Triangle
- References and Resources
How does the Kanizsa Triangle work?
The Kanizsa triangle illusion works by exploiting the way our brain processes visual information. The brain tends to group together similar elements in an image to form a coherent whole, a process called “Gestalt grouping” . In the case of the Kanizsa triangle, the brain groups the three partially-overlapping circles with white edges together and interprets them as the edges of a triangle, even though the triangle is not physically present.
Another aspect that is thought to contribute to the illusion is the way the brain uses “Amodal completion” to perceive objects. Amodal completion refers to the brain’s ability to fill in missing information to complete an object or shape. In this case, the brain fills in the missing parts of the triangle by connecting the three white crescents of the circles together, creating the illusion of a complete white equilateral triangle.
Additionally, the visual cues of the overlapping circles and the angles of the white crescents contribute to the perception of the triangle as well, making it look as if the triangle is emerging from behind the circles, even though it is not physically present.
Overall, the Kanizsa triangle works by exploiting the brain’s ability to group together similar elements and fill in missing information to create the illusion of a complete, non-existent triangle.
Versions of the Kanizsa Triangle
The following are some alternate versions of the Kanizsa Triangle:
Illusions like the Kanizsa Triangle
Illusory contour illusions are a type of visual illusion in which the brain perceives contours or edges that are not physically present in an image.
These illusions can be created by using a variety of visual cues, such as shading, texture, or the arrangement of simple shapes, to create the illusion of a more complex shape. Some examples of illusory contour illusions include:
The Muller-Lyer illusion: an illusion in which two lines of the same length appear to be of different lengths due to the presence of arrowheads at the ends of the lines.
The Poggendorff illusion: an illusion in which two lines that are parallel in reality appear to be skewed or converging due to the presence of a third shape in the foreground.
The Café Wall illusion: an illusion in which the lines that form a tiled wall appear to be skewed or distorted due to the presence of contrasting colored tiles.
The Zöllner illusion: an illusion in which parallel lines appear to be skewed or converging due to the presence of intersecting lines at an angle.
All these illusions work by exploiting the way the brain processes visual information and the way it interprets the relationship between different elements in an image. Illusory contours are thought to be created by the activity of neurons that respond selectively to edges and contours in the visual field, which can be influenced by different visual cues.
Discovery of the Kanizsa Triangle
The Kanizsa triangle is a visual illusion that was first described by the Italian psychologist Gaetano Kanizsa in 1955.
Gaetano Kanizsa (1913-1993) was an Italian psychologist and neuropsychologist, known for his research in the field of visual perception and his contributions to the understanding of visual illusions. He is most famous for his work on amodal completion, which refers to the brain’s ability to fill in missing information to complete an object or shape, and for his description of the Kanizsa triangle, one of the most famous and studied amodal completion illusion.
He was a professor of Psychology at the University of Trieste in Italy, and his research focused on the relationship between perception and reality. He also developed the concept of “subjective contours” which refers to the ability of the brain to perceive contours that are not physically present in an image, and was a pioneer in the field of neuropsychology. His work has had a significant impact on the field of cognitive psychology and has influenced the work of many researchers in the field of visual perception.
References and Resources
Check out our complete list of illusions.