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Korte's third law of apparent motion

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In psychophysics, Korte's third law of apparent motion[1] is an observation relating the phenomenon of apparent motion to the distance and duration between two successively presented stimuli.[2]

Formulation

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Korte's four laws were first proposed in 1915 by Adolf Korte.[3] The third law, particularly, describes how the increase in distance between two stimuli narrows the range of interstimulus intervals (ISI), which produce the apparent motion.[4] It holds that there is a requirement for the proportional decrease in the frequency in which two stimulators are activated in alternation with the increase in ISI to ensure the quality of apparent motion.[4] One identified violation of the Korte's law occurs if the shortest path between seen arm positions is not possible anatomically.[5] This was demonstrated by Maggie Shiffrar and Jennifer Freyd using a picture that showed a woman demonstrating two positions. This highlighted the problem in taking the shortest path to perform the alternating postures.[5]

The laws were composed of general statements (laws) describing beta movement in the sense of "optimal motion".[6] These outlined several constraints for obtaining the percept of apparent motion between flashes: "(1) larger separations require higher intensities, (2) slower presentation rates require higher intensities, (3) larger separations require slower presentation rates, (4) longer flash durations require shorter intervals .[7]

A modern formulation of the law is that the greater the length of a path between two successively presented stimuli, the greater the stimulus onset asynchrony (SOA) must be for an observer to perceive the two stimuli as a single mobile object. Typically, the relationship between distance and minimal SOA is linear.[2]

Arguably, Korte's third law is counterintuitive. One might expect that successive stimuli are less likely to be perceived as a single object as both distance and interval increase, and therefore, a negative relationship should be observed instead. In fact, such a negative relationship can be observed as well as Korte's law. Which relationship holds depends on speed.[1] Korte's law also involves a constancy of velocity through apparent motion and it is said that data do not support it.[8]

References

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  1. ^ a b Gepshtein, S.; Kubovy, M. (2007). "The lawful perception of apparent motion". Journal of Vision. 7 (8): 9. doi:10.1167/7.8.9. PMID 17685816.
  2. ^ a b Miller, G. F.; Shepard, R. N. (1993). "An objective criterion for apparent motion based on phase discrimination". Journal of Experimental Psychology: Human Perception and Performance. 19 (1): 48–62. doi:10.1037/0096-1523.19.1.48. PMID 8440988.
  3. ^ Korte, Adolf (1915). "Kinematoskopische Untersuchungen" [Cinematoscopic investigations]. Zeitschrift für Psychologie (in German). 72: 193–296.
  4. ^ a b Watanabe, Takeo (1998). High-level Motion Processing: Computational, Neurobiological, and Psychophysical Perspectives. Cambridge, MA: MIT Press. p. 26. ISBN 0262231956.
  5. ^ a b Rosenbaum, David A. (2017). Knowing Hands: The Cognitive Psychology of Manual Control. New York: Cambridge University Press. p. 207. ISBN 9781107094727.
  6. ^ Roeckelein, Jon E. (1998). Dictionary of Theories, Laws, and Concepts in Psychology. Westport, CT: Greenwood Publishing Group. p. 283. ISBN 0313304602.
  7. ^ Wagemans, Johan (2015). The Oxford Handbook of Perceptual Organization. Oxford: Oxford University Press. p. 488. ISBN 9780199686858.
  8. ^ Kolers, Paul A. (1972). Aspects of Motion Perception: International Series of Monographs in Experimental Psychology. Oxford: Pergamon Press. p. 19. ISBN 9781483186948.