The purposes of this study include: (1) determining whether socioeconomic status (SES) or verbal ability (VA) exerts greater influence on childrens' performance of Piagetian tasks; (2) devising an instrument for measuring childrens' level of cognitive development which does not depend on verbal ability alone; and (3) adapting materials for teacher…

Analysis of 65 children over a 4-year period on tests of operational and causal thinking offers support for Piaget's notion of stage progression. In kindergarten and grade one, the majority of children in this longitudinal study were between preoperational and the achievement stage of operational thought. By grade two, the majority had attained…

Stochastic difference equations of the Box-Jenkins form provide an adequate family of models on which to base the stochastic theory of human growth processes, but conventional time series identification methods do not apply to available data sets. A method to identify structure and parameters of stochastic difference equation models of human…