Achieving a new dimension: children integrate three stimulus dimensions in volume estimations

Although J. Piaget (1968) assumed that children up to 7 years old are unable to consider more than 1 stimulus dimension in their judgments, subsequent research has demonstrated that preschoolers can consider 2 dimensions, such as the width and length of rectangles to estimate their area (F. Wilkening, 1979). The present study addressed the question of whether children can also take 3 stimulus dimensions into account. Kindergartners, 1st and 3rd graders, and adults (N = 73) estimated the volume of cuboids that required the consideration of 3 dimensions: width, height, and length. The results showed that the majority of kindergartners already based their volume estimations on all 3 dimensions. A considerable proportion of kindergartners even integrated width, height, and length multiplicatively. There was no dramatic improvement with age, implying the implicit understanding of volume to develop relatively early in childhood. The results are discussed in light of children's cognitive competencies concerning multidimensional reasoning.