ABSTRACT
There are a number of more recent attempts to establish a typology of visual illusions according to type of distortion. For instance, Oyama utilized three major classifications. The first included illusions of angle, direction, straightness, and curvature–the equivalent of Boring’s illusions of direction. The remaining two classes were produced by subdividing illusion of extent into illusions of length and distance and illusions of size and area. Any illusion researcher can easily verify that there are large individual differences in the responsiveness of observers to various illusions. Given many sources of distortion, it seemed likely that different individuals might show different levels of structural involvement or different dispositions toward the use of particular strategies. Hence the very individual differences that ordinarily add to the variability of the data in illusion studies could be used to establish a taxonomy by ascertaining which illusions covary systematically.
