Mental test data cited by H. T. Epstein as supporting his theory that new concepts should be taught during periodic spurts in childhood intellectual development (at 3-10 months; and 2-4, 6-8, 10-12 or 13, and 14-16 or 17 years) are reanalyzed. It is found that the data do not substantiate Epstein's conclusions. (TJH)

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…