A form perception theory is proposed in an attempt to understand problems in mental rotation and in perception of forms rotated in the frontal-parallel plane. The theory, along with distinctions among four types of information, was supported by two mental and three visual experiments with 74 undergraduate students. (TJH)

The theory is developed and contrasted with other theories of pattern recognition in which concepts such as stimulus generalization, tuned detectors, and preprocessing play major roles. A relation of this theory to problems encountered among disabled readers ("dyslexics") is also brought out. (Author/BJG)