Reports on three studies which investigated the development of the concept of horizontality in subjects from nursey school through college age. Normative data collected allowed for evaluation of Piaget's stages and for differences due to age, sex, and apparatus shape and orientation. (ED)

Describes and discusses the rule-assessment approach, a new research strategy for studying developmental sequences in children's acquisition of knowledge. Four experiments were conducted to illustrate the utility of this approach across a variety of concepts and a wide range of ages (three-year-olds to college students). (Author/CM)

Examined sex differences in eighth and tenth graders' and college students' use of elaboration in paired associate learning. Findings indicate that, as males and females became more proficient strategy users, sex differences diminished under more favorable task conditions that encouraged strategy use but remained constant under less favorable…

The Conceptual Learning and Development (CLD) Model specifies four levels of concept attainment (concrete, identity, classificatory, and formal) and three uses of concepts (problem solving, subordinate-supraordinate, and principles). Longitudinal and cross-sectional studies of concept attainment may be conducted. The results of this study of 300…