What conservation anticipation reveals about cognitive change

A long-running debate about the nature of the thinking involved in conservation judgments resulted in postulating the existence of two different processes. According to the pluralist approach to cognitive development, the two processes can be simultaneously activated with different weights for different children and are likely to interact. A semi-longitudinal study that tests the pluralist approach is reported. The experimental procedure was based on earlier work by Acredolo and Acredolo, 1979, Acredolo and Acredolo, 1980. Children from the last year of nursery school (mean age: 5 years and 6 months) were individually tested in two successive occasions separated by a 3-month interval. The first test occasion consisted of a sequence of liquid-conservation-anticipation and level anticipation tasks. This same sequence was reproduced during the second test occasion, which ended with a classical conservation task. Observed patterns of correct-incorrect answers contradict the predictions of a developmental sequence assumed by the Piagetian model. The patterns of change were compatible with a pluralist approach which hypothesizes different routes in the development of conservation.