Studies of preverbal infants exposed to a bilingual environment have unveiled the existence of important similarities, but also significant differences in the way monolinguals-to-be and bilinguals-to-be solve the problem of language acquisition. In this paper, I review these studies and I argue that some apparent bilingual failures are the…

Studying human development involves describing, explaining, and optimizing intraindividual change and interindividual differences in such change and, as such, requires longitudinal research. The selection of the appropriate type of longitudinal design requires selecting the option that best addresses the theoretical questions asked about…

Argues that the status of the concept of equilibration is classified by considering Piagetian theory as a research program in the sense elaborated in 1974 by Lakatos. A pilot study was made to examine the precision and testability of equilibration in Piaget's 1977 model.(Author/RH)

Five prototypic issues derived from a dialectical perspective are proposed: relationism, evolving reciprocity, probabilism, timing, and the nonequivalent temporal metric. It is argued that these issues, while not changing the scientific method, have implications for specific procedures. (Author)

Evaluates empirical studies on child development. Suggests that most such research consists of studies of a priori, nonempirical, logical relations between concepts, whose definitions guarantee the relationship studied. Argues that hypotheses are empirical if variables involved are semantically and logically independent. Research that is not based…

This paper represents a call for the rehabilitation and liberalization of the term learning. Preliminary steps for a revived theory of development and learning are described, including a consideration of such topics as compatibility or naturalness, accessibility and flexibility of learning, and processes of induction. Specific recommendations for…

Five symposium papers evaluate the usefulness of ideas associated with the life-span view for enriching, highlighting, or expanding issues, theory, and research pertinent to change processes during infancy, childhood, adolescence, and adulthood, and for intervention programs during these periods. (Author/MP)

Comments on the ideas espoused by Smedslund (PS 522 552) in this issue. Agrees to the idea of spending more intellectual energy in distinguishing between a priori and empirical hypotheses but emphasizes that concepts are not always accurate reflections of reality and that even empirical disconfirmation of an a priori hypothesis sometimes can…