Abstract
This study examined the developmental sequence and the teaching method of the action of making development drawings (AMD). In Experiment I, 160 second, third, fourth, and sixth grade children were tested to draw the development drawings of four objects illustrated in oblique drawings. In Experiment II, based on the performance level of the development drawing tests for 33 third-grade children, six pairs of matched subjects who had not yet acquired AMD were selected. The training program of six steps consisted of the following four subordinate operations which were assumed to underlie AMD; abstraction of all surfaces of the given figure, decision of the base, decision of the cutting lines, and development of the surfaces. Main results were as follows: (1) The development of AMD was accelerated from fourth grade and was nearly complete in sixth grade. (2) The training program raised the level of AMD from low to high. (3) Generalization of each operation based on the oblique drawing was necessary for the formation of AMD.
