Abstract
This study aimed at investigating the process of acquisition of water surface representation. Children were shown the test papers (a),(b) and (c) on which were drawn the bottles tilted at the angle of 0, 22.5, 45, 67.5, 90, 112.5, 135, 157.5 and 180, and were asked to draw the water surface in these bottles. In test (a) 9 round bottles were drawn on the horizontal table, in test (b) 9 square bottles on the horizontal table and in test (c) 9 square bottles on the 22.5° tilted stand.
Ss were 413 children in every other grade from 1st in elementary school through 9th in junior high school. Ss were classified into 5 stages according to the quality of their drawings.
Stage I (12 Ss): Water surface is drawn parallel to the bottom of bottle intest (b).
Stage II(77 Ss): Water surface in the bottles is drawn obliquely in test (a) and (b).
Stage III(65 Ss)Water surface is drawn horizontally only in test (a).
Stage IV(131 Ss): Water surface is drawn horizontally in both test (a) and (b).
Stage V(122 Ss): Water surface is drawn horizontally in all three tests.
Most of 1st graders belonged to StageII, 3rd graders were distributed almost equally from Stage II through Stage IV, and most of 5th graders were in StageIV. It was not until 9th grade in junior high school that 2/3 of Ss attained StageV. This result that the chronological age to reach Stage IV was 9-11 years old agreed with Piaget's findings, but the level of Stage V was not investigated experimentally in his studies. It was shown with regard to the attainment of StageV that water surface representation in drawing was easily influenced by the cue of the oblique table line on which bottles were placed.
Then, 20 Ss, that is, 5 Ss in each stage except Stage V were trained to attain higher stage. The core of the method of training was the introduction of cognitive conflict to the Ss. Program of training to develop the Ss from Stage I to Stage II was as follows. S had a dialogue with E, observed the surface of blue plasticine half-filled in the bottle which S himself tilted every 22. 5°, and was asked what happened in the bottle. Program of training to develop Ss to Stage III was as follows. The S observed the surface of water in the round bottle which S himself tilted according to the direction of E roughly to match every 22. 5°on the horizontal top of a desk, and was asked to compare the water surface with the horizontal line drawn on the background paper. Training to develop to Stage IV and StageV was undertaken in the same way as above mentioned except that the square bottle were used instead of round ones and that it was placed on the horizontal top of the desk in the former or on the oblique stand in the latter. The results were as follows. All the Ss gained in the number of correct responses, but those who remained in the same stage were 5 in number, those who developed 1 stage were 9, and those who developed 2 stages or more were 6. These results to some extent support the hypothesis that it is possible to promote the development of water surface representation by introducing cognitive conflict.
