Portland State University. Department of Psychology
Date of Award
Master of Science (M.S.) in Psychology
Digitized archived scanned photocopied typescript. 30 pages,
Optical illusions -- Psychological aspects, Vision
Current explanations for the Ames Trapezoid Illusion are based upon the the absence of cues: the illusion is said to occur at chance. A review of recent literature showed that: (a) the illusion varies in frequency as a function of target shape (b) that the dominant cue to reduce the frequency of the illusion is the variant in retinal height. Based upon the dominance of this cue a new model was presented. Following this model it was hypothesized that observers viewing partial rotation when the target produces the greatest difference in the retinal height of the ends would determine the true direction more accurately than observers viewing the same target when the differences in the retinal height was least. The results confirmed the hypothesis.
Kelly, Daniel Robert, "Ames Trapezoid Illusion: A New Model" (1971). Dissertations and Theses. Paper 1519.