i need every information about the Jastrow- illusion, especially: - which theory does explain this effect - can you use the rules of gestalt-theory as an explanation

-- birgitta stein (birgitta_stein@gmx.de), May 03, 2001

Answers

I suggest Stanley Coren of UBC be asked. He has undertaken more research than most into illusions. Many illusions do not have a well-established explanation and most explanations are very poor. The Ponzo and Muller-Lyer are a case in point. The perspective explanations of illusions are especially inadequate. JMK

-- j.m. kennedy (kennedy@scar.utoronto.ca), May 03, 2001.

I do not know the answer to your question, but a search of "jastrow illusion" on the APA's PsychInfo brings up the following recent articles you may want to have a look at.

Experimental research on geometrical illusions presented in a special environment: The effects of various stimulus-presenting conditions on the generating factors of geometrical illusions. By Goto, Takuo; Kohmura, Kazumi; Teramoto, Kazumi; Ohya, Kazuo. Japanese Psychological Review. 1995 Vol 38(4) 520-538

Theoretical parallels between the Ponzo illusion and the Wundt-Jastrow illusion. By Pick, David F.; Pierce, Kent A. Perceptual & Motor Skills. 1993 Apr Vol 76(2) 491-498

Illusions and knowing what is real. By Kennedy, John M.; Green, Christopher D.; Nicholls, Andrea; Liu, Chang Hong. Ecological Psychology. 1992 Vol 4(3) 153-172.

Directional hypokinesia in spatial hemineglect: A case study. By Bottini, G.; Sterzi, R.; Vallar, G. Journal of Neurology, Neurosurgery & Psychiatry. 1992 Jul Vol 55(7) 562-565.

Visual neglect for far and near extra-personal space in humans. By Pizzamiglio, Luigi; Cappa, Stefano; Vallar, Giuseppe; Zoccolotti, Pierluigi; et al. Cortex. 1989 Sep Vol 25(3) 471-477

Size-distance perception in preschool children. By Tronick, Edward; Hershenson, Maurice. Journal of Experimental Child Psychology. 1979 Feb Vol 27(1) 166-184.

The Wundt-Jastrow illusion in the study of spatial hemi-inattention. By Massironi, Manfredo; Antonucci, Gabriella; Pizzamiglio, Luigi; Vitale, Maura V.; et al. Neuropsychologia. 1988 Vol 26(1) 161-166

And of course the classics that got it all started:

Studies from the laboratory of experimental psychology of the University of Wisconsin - II. By Jastrow, Joseph. American Journal of Psychology. 1892 Apr Vol 4(3) 381-428.

Studies from the laboratory of experimental psychology of the University of Wisconsin. By Jastrow, Joseph. American Journal of Psychology. 1891 Dec Vol 4(2) 198-223.

-- Christopher Green (cgreen@chass.utoronto.ca), May 04, 2001.

This is a trick question! There are no correct explanations of any of this class of geometric illusions (a nice list of which can be found at http://humanities.lit.nagoya-u.ac.jp/~illusion/gallery/NVEG/index_e.ht ml

).

In my 2nd Year Perception class I take a random geometric illusion, usually the Mueller-Lyer and go through a number of possible "explanations". I choose some based on "bottom up principles" (that the reason for the illusion is in the stimulus and creates the illusion as information flows from lower to higher parts of the perceptual system)and others based on "top down principles" (that the reason for the illusion is NOT in the stimulus but is imposed from 'higher' cognitive processing involving things like memories, interpretations and/or emotions). I point out that "explanations" in each of these classes do not rule out other explanations in either the same or other classes and that the explanations offered usually tell us more about the explainer than the illusion.

So in answer to the original query, which theory explains the effect? Answer: they all do (Gestalt, Gibson, neurophysiology, ecological, perspective, etc...). Which one is right? They all are (in as much as these theory-of-visions are valid)! Can you use the rules of gestalt-theory? Yes, of course!

-- Laurence Harris (harris@yorku.ca), June 03, 2001.