MATRICES, THREE BY THREE: CLASSIFICATION AND SERIATION.

In Piagetian theory, transition to the stage of concrete operations is characterized by a cognitive structure wherin the 4 logical groupings associated with simple and multiple classification and simple and multiple seriation become operational at roughly the same time. The evidence for the emergence of the ability for classification and simple seriation in Western children at about age 7 is overwhelming. That for multiple seriation is unimpressive at least in quantity. This paper investigates the development of the ability for double seriation in children aged 5-8 years and finds that there is a developmental lag between the emergence of the ability for cross-classification and that for double seriation. This results is considered to have implications beyond that of revising age norms. An attempt is made to relate it to the differences existing between the Geneva ad Harvard approaches to interpreting cognitive growth. [ABSTRACT FROM AUTHOR]