CHILDREN'S MENTAL ROTATION: COMPETENCE AND PROCESS.

Spatial ability has been studied primarily through two perspectives: the developmental and the information processing orientations. This research combines these approaches. Mental rotation (the ability to mentally rotate objects) was examined by focusing on the developmentalists' concern for age of acquisition of this ability and the information theorists' attention to stimulus factors influencing this competency. Sixty students, twenty each in kindergarten, third, and fifth grade, participated in the study; there were equal numbers of males and females for every grade. Each student was shown 240 slides featuring two line drawings, a standard stimulus on the left, a trial stimulus on the right. For each slide, the subject indicated whether the stimuli were alike or different by pressing an appropriate button. The standard stimulus was always upright; the trial stimulus was upright or was rotated to 45, 90, 135, or 180 degrees. The four standard stimuli used each consisted of a circle. They differed, however, by possessing or lacking a cone atop the circle and by having an orthogonal or oblique internal axis. Each standard stimulus was paired with a trial stimulus which was a: (1) match, (2) reflection, or (3) internal mismatch (orthogonal axis paired with an oblique axis and vice-versa) of the standard stimulus. When the subjects indicated their judgment, their choice and their response time were recorded, providing both competency and process data. A series of analyses were performed, the outcome of one directing the course of the next. Two analyses of variance were made on competency data (for zero and for the rotated positions) and one on process data. The research yielded several significant findings, the most important of which was an interaction between the nature of the to-be-rotated stimulus and the degree of the rotation. This interaction indicated that short reaction times occurred when the internal axis of the test item was orthogonal; long reaction times occurred when the axis was oblique. These results were discussed with regard to developmental and information processing views of mental rotation