Past research on the development of referential communication abilities in children does not provide a basis for explaining precisely why communicative effectiveness increases. The common assumption is that developments in role-taking facilitate the child's ability to adapt to hearers. A reasonable alternative explanation is that a child's…

In order to determine the cognitive development of Navajo children in terms of Piagetian conservation of number, mass, and continuous quantity, 168 Navajo children at seven different age levels from 5 to adult were presented with a series of three conservation tasks. The tasks consisted of a standard object and an equivalent object that could be…