HORIZONTALITY OF WATER-LEVEL - A NEO-PIAGETIAN DEVELOPMENTAL REVIEW

Piaget and Inhelder devised the water level task to study children's progressive understanding of the spatial-coordinate system. Subjects were presented a rectangular-shaped bottle half-filled with water. They were then shown a similar empty bottle, which the researchers tilted at various angles. For each angle of inclination, the subjects had to indicate the direction of the water level, under the assumption that this bottle was half-filled with water. Results showed that different patterns of errors were typical of the preoperational and concrete-operational developmental stages. This chapter examines relevant data and the available developmental models related to water level invariant. Motivated by the empirical facts that emerge from the review, it also summarizes a neo-Piagetian model that was proposed in the 1960s but that had little impact on subsequent published work. This model actually predicted many of the empirical results obtained in the 1970s and 1980s, facts that other published models cannot explain. The model was based on theoretical assumptions that more recently might be seen as anticipating aspects of the functional architecture that connectionistheural modeling has explicitly brought to the fore. Liben emphasized the importance of general developmental theories, and their explication of task performances, to clarify the processes that generate the data on spatial cognition. To highlight from the start major controversial issues that the water level task (the problem of developmental acquisition of its spatial invariant) brings to light, the chapter begins with a brief examination of some recent cognitive-developmental theories that were directly addressed to the water level task and are presented as an alternative to Piagetian and neo-Piagetian theorizing. © 1991 Academic Press Inc.