Development of the ability to judge relative areas: Role of the procedure of placing one object on another

This study examined the role of the cognitive procedure of superimposition in the development of an area concept. Forty-five children from age 4 to 6 were presented with target squares or rectangles and asked to choose one that was equal to two standard rectangles in area. In the perceptual judgment condition, children compared these figures just by looking; whereas, in the manipulative judgment condition, they placed the standard figures on the targets. Children were also asked to compare the sizes of geometric figures, and their spontaneous strategies were observed. The children performed better under the manipulative judgment condition than under the perceptual judgment condition, and their performance was facilitated when one target could be overlapped completely with the standard figures. Each of these facilitating effects was found independently of the other only in children who used the strategy of superimposition spontaneously for comparing sizes.