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)

Several experiments were undertaken with a total of 111 undergraduates. Subjects attempted to imagine how three-dimensional novel wire objects would appear from viewpoints other than that of the subject. Subjects were unable to perform this task without making use of strategies that circumvent the process of visualization. (TJH)