This study investigated the linguistic components of Piaget's class-inclusion task. First, hierarchical classification is examined from both Piagetian and linguistic theory points of view. Then, two general characteristics of child thinking that relate to the different interpretations of the responses to classification questions are discussed: (1)…

The major purpose of this study was 1) to investigate the development of the concept of a unit of measure and the coordination of unit size and the number of units 2) to relate this development to the development of conservation and 3) to determine the role of equivalence and nonequivalence relations in certain conservation and measurement…