Contrary to Piaget’s position (Piaget, 1960, 1967, 1968), we argue that reversibility is both logically and psychologically irrelevant to conservation, because logically, simply inverting the conservation transformation provides no information about the property being conserved, and psychologically, because nonconservers give evidence of reversibility. Specifically, the data indicate that nonconservers think that an increase in a clay ball’s temperature reduces its weight, and a decrease in its temperature increases weight. © 1969, Psychonomic Journals, Inc.. All rights reserved.
