The theory of conceptual fields is a developmental theory. It has two aims: (1) to describe and analyse the progressive complexity, on a long- and medium-term basis, of the mathematical competences that students develop inside and outside school, and (2) to establish better connections between the operational form of knowledge, which consists in…

Growing out of a child's cognitive developmental history, formal operation becomes established at about the age of 12-15 years. The essence of the logic of cultured adults and the basis for elementary scientific thought are thereby provided. The rate at which a child progresses through the developmental succession may vary, especially from one…

Responds to Noam's (PS 524 984) and Cicchetti's (PS 524 985) articles in this issue. Suggests that researchers should turn to the coactions of the internal and the external constraints on development that codetermine performance. States the position that cognitive developmental theory, when sensitized to intra- and interindividual differences,…

Concepts from the logic of modalities are applied to the life cycle to elaborate a new theory of adult and late-life development. Four logical modalities are described, each cognitively and emotionally governing discrete periods of life. It is hypothesized that optimal development in adult life includes explicit awareness of these modalities. (RH)

Argues that linguistic communication allows the incorporation of individual, microsociological, and macrosociological levels of analysis into a general theory of action. (RH)

Reviews Thelen and Smith's book and its account of "how knowing develops from doing." Concentrates on the nature of dynamic systems. (DR)

Examines the role attributed to cultural mediation in Piaget's and Vygotsky's theories. Mediation of human action by cultural artifacts was central to Vygotsky's account of human development, but less important for Piaget. Vygotsky's claims regarding social origins of individual mental processes need to be understood in light of claims regarding…

Piaget's theory has been characterized as descriptive and not explanatory, not qualifying as causal explanation. Piaget was consistent in showing how his theory was both explanatory and causal. Vygotsky also endorsed causal-genetic explanation but, on the basis of knowledge of only Piaget's earliest works, he claimed that Piaget's theory was not…

Compares Piaget's and Vygotsky's interpretations of transmission and transformation. Notes that differences are apparent in the preformation of knowledge, availability of a third alternative to nature and culture, and unity and identity in social interaction. Vygotsky was concerned about the novel transformation of the learner; Piaget, with the…

Comments on van Geert's mathematical model of Vygotsky's zone of proximal development, in this issue. Supports van Geert's use of a nonlinear model, noting that linear statistical models overlook variability in psychological phenomena. Discusses the time asymmetry in van Geert's model, which does not account for a subject's "developmental…

Notes contemporary models of human development have expanded to address a wider set of issues underlying personal change. Discusses the social cognitive model of self-regulatory development. Emphasizes the crucial development of self-regulatory competence: the point at which the processes of development become fully and reciprocally interactive…

Compares differences in Noam's (PS 524 984) and Cicchetti's (PS 524 985) viewpoints to their shared idea that our understanding of human development has much to gain from the emerging field of psychopathology. Describes Noam's approach as intended to blur the boundaries between optimal and pathological development, and Cicchetti's approach as more…

Discusses the two major theoretical traditions from which the ideas discussed in the Noam (PS 524 984) and the Cicchetti (PS 524 985) articles in this issue are drawn. Describes their divergences from traditional Piagetian and attachment theorists, and the approaches each has taken to common themes in their work. Concludes by setting out…

Argues that the limited resources with which organisms start their development make possible certain kinds of learning which otherwise would be highly problematical. Discusses limitations of the cognitive structure of the organism, learning, and its problems in connectionism. Maintains that the knowledge gained from efforts to overcome problems…

Comments on Raftopoulos article (PS 528 649) on facilitative effect of cognitive limitation in development and connectionist models. Argues that the use of neural networks within an "Artificial Life" perspective can more effectively contribute to the study of the role of cognitive limitations in development and their genetic basis than…