Infant perception of the shapes of tilted plane forms

Abstract

This paper describes three experiments based on Caron, Caron, and Carlson (1979) . In each case, 3-month-old infants were familiarized with a plane form presented at various tilts. In three subsequent test trials they saw the familiar form in a familiar (60°) orientation, the familiar form in a novel frontoparallel orientation (novel-orientation test), and a novel form in frontoparallel (novel-form test). The novel form was the frontoparallel projection of the familiar form when tilted at 60°. In Experiment 1, recovery of fixation occurred in the novel-form test when the infants were familiarized with a rectangle and the novel form was a trapezoid. No recovery occurred when both the familiar and novel forms were irregular quadrilaterals. The results for the rectangle were interpreted as evidence of shape constancy. The results for the irregular forms were attributed to a poor resolution of these forms. In Experiment 2, the infants were familiarized with a rectangle as in Experiment 1. However, the novel-orientation test stimulus was reduced in size so that its area equalled that of the trapezoid seen in the novel-form test (novel-size test). While a recovery of fixation occurred in the novel-form test, no recovery occurred to the reduction of size in the novel-size test. This was taken as evidence that the rectangle/trapezoid discrimination was based on the perception of form rather than size. In Experiment 3, the procedure of Experiment 1 was repeated but the infants were familiarized with either a parallelogram or a trapezoid. In neither case was there a recovery in the novel-form test. It was concluded that the rectangle/trapezoid discrimination was based upon a perception of orthogonality.