We investigated whether 6- and 7-year-olds and 9- and 10-year-olds, as well as adults, process object dimensions independent of or in interaction with one another in a perception and action task by adapting Ganel and Goodale's method for testing adults (Nature, 2003, Vol. 426, pp. 664-667). In addition, we aimed to confirm Ganel and Goodale's results in adults to reliably compare their processing strategies with those of children. Specifically, we tested the abilities of children and adults to perceptually classify (perception task) or grasp (action task) the width of a rectangular object while ignoring its length. We found that adults process object dimensions in interaction with one another in visual perception but independent of each other in action, thereby replicating Ganel and Goodale's results. Children processed object dimensions interactively in visual perception, and there was also some evidence for interactive processing in action. Possible reasons for these differences in object processing between children and adults are discussed.