Difference between revisions of "Ponzo illusion" - New World Encyclopedia

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An example of the Ponzo Illusion. Both horizontal lines are the same size.

The Ponzo illusion is an optical illusion where a pair of converging lines distorts the perception of two identically sized lines.

Discovery

The Ponzo illusion was first published by the Italian psychologist Mario Ponzo (1882-1960) in 1913. Ponzo suggested that the human mind judges an object's size based on its background, and illustrated this idea by drawing two identical lines across a pair of converging lines.

Description

The Ponzo illusion is often illustrated with two converging lines that mimic railroad tracks disappearing into the distance. Two horizontal lines or bars are placed across these "tracks", one higher than the other. When looking at the image, viewers routinely see the upper bar (where the converging lines are closer) as larger than the lower bar. In reality, the two bars are of identical size.

Explanation

The effect of the Ponzo illusion is often attributed to linear perspective. The upper line looks longer because we interpret the converging sides according to linear perspective as parallel lines receding into the distance. In this context, we interpret the upper line as though it were farther away, so we see it as longer. In the three dimensional world, an object located farther away would have to be larger than a nearby object for both to produce retinal images of the same size. This explanation is often referred to as the perspective hypothesis.

The more visual cues present surrounding the two horizontal lines, the more powerful the illusion. The framing effect, where objects that appear to fill an enclosing border appear larger than the same object surrounded by a larger frame, also contributes to the illusion. The difference in the separation or gap of the horizontal lines from the framing converging lines helps to create the sense that the upper bar, which is closer to the bordering lines, is larger than the lower one.

Interestingly enough, the Ponzo illusion also appears to be present in other species. Japanese studies have show that pigeons, rhesus monkeys, and chimpanzees all perceive the Ponzo illusion, although the relative strength of various contributing factors like figure orientation was different among each species.^[1]

Applications

In addition to providing a means of studying the way the human visual and perceptual systems operate, the Ponzo illusion has also provided a way to help determine how other species perceive information.

Some researchers believe that the Moon illusion is an example of the Ponzo illusion, with trees and houses playing the role of Ponzo's converging lines.^[2]

Notes

↑ Oyama, Tadasu, and Takuo Goto. "Editorial: Studies on optical illusions in Japan" Japanese Psychological Research 49 (1), 1-6. Retrieved October 25, 2007.
↑ The Moon looks bigger on the horizon because the air acts like a lens, magnifying it Retrieved September 14, 2007.

References
ISBN links support NWE through referral fees

Renier L, De Volder AG (2005). "Cognitive and brain mechanisms in sensory substitution of vision: a contribution to the study of human perception." Journal of Integrative Neuroscience, Special Edition in Honor of Paul Bach-y-Rita, 4:489-503.
Renier L, Laloyaux C, Collignon O, Tranduy D, Vanlierde A, Bruyer R, De Volder AG (2005). "The Ponzo illusion using auditory substitution of vision in sighted and early blind subjects." Perception, 34:857–867.

Credits

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History of "Ponzo illusion"

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[1] Oyama, Tadasu, and Takuo Goto. "Editorial: Studies on optical illusions in Japan" Japanese Psychological Research 49 (1), 1-6. Retrieved October 25, 2007.

[2] The Moon looks bigger on the horizon because the air acts like a lens, magnifying it Retrieved September 14, 2007.

[1]

[2]

@@ Line 5: / Line 5: @@
 [[Image:Ponzo illusion.gif|250px|thumb|right|An example of the Ponzo Illusion. Both horizontal lines are the same size.]]
-The '''Ponzo illusion''' is an [[optical illusion]] that was first demonstrated by the [[Italy|Italian]] psychologist [[Mario Ponzo]] (1882-1960) in 1913. He suggested that the [[human mind]] judges an object's size based on its background. He showed this by drawing two identical lines across a pair of converging lines, similar to [[railway]] tracks. The upper line looks longer because we interpret the converging sides according to [[linear perspective]] as parallel lines receding into the distance.
+The '''Ponzo illusion''' is an [[optical illusion]] where a pair of converging lines distorts the perception of two identically sized lines.
-In this context, we interpret the upper line as though it were farther away, so we see it as longer – a farther object would have to be longer than a nearer one for both to produce retinal images of the same size.
-Some researchers believe that the [[Moon illusion]] is an example of the Ponzo illusion, with trees and houses playing the role of Ponzo's converging lines.<ref>[http://www.space.com/scienceastronomy/top5_myths_020903-2.html The Moon looks bigger on the horizon because the air acts like a lens, magnifying it] Retrieved September 14, 2007.</ref> Foreground objects trick our brain into thinking the moon is bigger than it really is.
+==Discovery==
+The Ponzo illusion was first published by the [[Italy|Italian]] psychologist [[Mario Ponzo]] (1882-1960) in 1913. Ponzo suggested that the [[human mind]] judges an object's size based on its background, and illustrated this idea by drawing two identical lines across a pair of converging lines.
-One of the explanations for Ponzo illusion is the 'Perspective hypothesis', which states that the perspective feature in the figure is obviously produced by the converging lines ordinarily associated with distance, that is, the two oblique lines appear to converge toward the horizon or a vanishing point. Another is the 'Framing effects hypothesis', which says that the difference in the separation or gap of the horizontal lines from the framing converging lines may determine, or at least contribute to the magnitude of the distortion.
+==Description==
+The Ponzo illusion is often illustrated with two converging lines that mimic railroad tracks disappearing into the distance. Two horizontal lines or bars are placed across these "tracks", one higher than the other. When looking at the image, viewers routinely see the upper bar (where the converging lines are closer) as larger than the lower bar. In reality, the two bars are of identical size.
+==Explanation==
+The effect of the Ponzo illusion is often attributed to [[linear perspective]]. The upper line looks longer because we interpret the converging sides according to [[linear perspective]] as parallel lines receding into the distance. In this context, we interpret the upper line as though it were farther away, so we see it as longer. In the three dimensional world, an object located farther away would have to be larger than a nearby object for both to produce retinal images of the same size. This explanation is often referred to as the ''perspective hypothesis''.
+The more visual cues present surrounding the two horizontal lines, the more powerful the illusion. The [[framing effect]], where objects that appear to fill an enclosing border appear larger than the same object surrounded by a larger frame, also contributes to the illusion. The difference in the separation or gap of the horizontal lines from the framing converging lines helps to create the sense that the upper bar, which is closer to the bordering lines, is larger than the lower one.
+Interestingly enough, the Ponzo illusion also appears to be present in other species. Japanese studies have show that pigeons, rhesus monkeys, and chimpanzees all perceive the Ponzo illusion, although the relative strength of various contributing factors like figure orientation was different among each species.<ref>Oyama, Tadasu, and Takuo Goto. [http://www.blackwell-synergy.com/action/showFullText?submitFullText=Full+Text+HTML&doi=10.1111%2Fj.1468-5884.2007.00327.x&cookieSet=1 "Editorial: Studies on optical illusions in Japan"] Japanese Psychological Research 49 (1), 1-6. Retrieved October 25, 2007.</ref>
+==Applications==
+In addition to providing a means of studying the way the human visual and perceptual systems operate, the Ponzo illusion has also provided a way to help determine how other species perceive information.
+Some researchers believe that the [[Moon illusion]] is an example of the Ponzo illusion, with trees and houses playing the role of Ponzo's converging lines.<ref>[http://www.space.com/scienceastronomy/top5_myths_020903-2.html The Moon looks bigger on the horizon because the air acts like a lens, magnifying it] Retrieved September 14, 2007.</ref>
+==Notes==
+<references/>
-This typical visual illusion also occurs in touch and with an audition-to-vision [[Sensory_substitution|sensory substitution device]]. However, prior visual experience seems mandatory to perceive it as demonstrated by the fact that congenitally blind subjects are not sensitive to it.
 ==References==
@@ Line 18: / Line 33: @@
 *Renier L, De Volder AG (2005). "[http://www.worldscinet.com/179/04/0404/S0219635205000999.html Cognitive and brain mechanisms in sensory substitution of vision: a contribution to the study of human perception]." ''Journal of Integrative Neuroscience, Special Edition in Honor of Paul Bach-y-Rita, '''4''':489-503''.
 *Renier L, Laloyaux C, Collignon O, Tranduy D, Vanlierde A, Bruyer R, De Volder AG (2005). "[http://www.perceptionweb.com/perabs/p34/p5219.html The Ponzo illusion using auditory substitution of vision in sighted and early blind subjects]." ''Perception, '''34''':857–867''.
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