Barberpole illusion
The barberpole illusion is a
History
In 1929,
In 1935, Hans Wallach published a comprehensive series of experiments related to this topic,[4] but since the article was in German it was not immediately known to English-speaking researchers. An English summary of the research was published in 1976[5] and a complete English translation of the 1935 paper was published in 1996.[6] Wallach's analysis focused on the interaction between the terminal points of the diagonal lines and the implicit aperture created by the edges of the pole.
Explanation
This illusion occurs because a bar or contour within a frame of reference provides ambiguous information about its "real" direction of movement. The actual motion of the line has many possibilities. The shape of the aperture thus tends to determine the perceived direction of motion for an otherwise identically moving contour. A vertically elongated aperture makes vertical motion dominant whereas a horizontally elongated aperture makes horizontal motion dominant. In the case of a circular or square aperture, the perceived direction of movement is usually
Individual motion-sensitive neurons in the visual system have only limited information, as they see only a small portion of the visual field (a situation referred to as the "aperture problem"). In the absence of additional information the visual system prefers the slowest possible motion: i.e., motion orthogonal to the moving line.[8] The neurons which may correspond to perceiving barber-pole-like patterns have been identified in the visual cortex of ferrets.[9]
Auditory analogue
A similar effect occurs in the
See also
- Screw (simple machine)– screws convert rotational motion to linear motion and exhibit the same mechanic
- Motion perception
- Auditory illusion
References
Notes
- ^ a b "Barber Pole Illusion". sandlotscience.com. Archived from the original on 28 November 2010. Retrieved November 14, 2010.
- ^ a b Massaro, Dominic W., ed. (Spring 2007). "Book Reviews: What Are Musical Paradox and Illusion?" (PDF). American Journal of Psychology. 120 (1). University of California, Santa Cruz: 123–170, 124, 132.
- ^ Guilford, J.P. (1929) "Illusory Movement from a Rotating Barber Pole." American Journal of Psychology 41: 686–687.
- S2CID 145400184.
- ^ Wallach, H. (1976). On perception. Quadrangle/New York Times Book Company. chap. IX.1
- ^ Wuerger, S., Shapley, R., & Rubin, N. (1996). "'On the visually perceived direction of motion' by Hans Wallach: 60 years later." Perception-London, 25: 1317–1368.
- doi:10.2298/psi0203209t. Archived from the original(PDF) on July 23, 2011. Retrieved November 26, 2010.
- ISBN 0-393-31967-9
- ^ Lees, Kevin (July 15, 2003). "Rethinking How the Brain Sees Visual Features: Duke neurobiologists study brain's visual-processing region". Duke News. Durham, North Carolina: Duke University. Archived from the original on July 26, 2010. Retrieved December 14, 2010.