Brian J. Rogers : “Delusions about Illusions: a critique of the illusion concept”


November 12, 2018
16:00 ~
CiNet 1F Conference Room

“Delusions about Illusions: a critique of the illusion concept”

Brian J. Rogers
Department of Experimental Psychology
Oxford University

Host : Izumi Ohzawa (PI)

Prof. Rogers is well-known for the book coauthored with Prof. I Howard:

Perceiving in Depth: Stereoscopic Vision (Oxford Psychology Series) 2012/2/24 Ian P. Howard, Brian J. Rogers

Do illusions exist or are we deluded about the concept? I am going to argue that the concept of illusion is a delusion. Traditionally, we draw a distinction between veridical and illusory perception by saying that in the former case our perceptions correspond with the physical reality whereas in the latter case there is a discrepancy. However, while there might be general agreement on what we perceive in particular circumstances, it is less clear how should we define what is the ‘physical reality’. It cannot be the ‘proximal’ stimulus (i.e. the retinal image) because, if it were, all the perceptual constancies would have to be regarded as illusions. Similarly, the ‘distal stimulus’ cannot be the reality because those situations in which the pattern of light reaching the eye is ‘projectively equivalent’ to another real world scene (such as the Ames Room or viewing a stereogram) would have to be regarded as illusions. A possible way out of the problem of what constitutes the ‘reality’ would be to define an illusion as a discrepancy between the information contained in the spatio-temporal patterning of light reaching the eye and what we perceive. But even this definition has problems.