This paper describes six experiments performed to investigate elementary school childrens' understanding of a proportionality concept, the concept of fullness. (CM)

Used single-subject analyses to examine the developmental difficulty of the ulterior motive question (the backward inverse inference) in five- and seven-year-olds. Results suggest that children's difficulties with ulterior motive information result both from the abstract nature and the logical form of the task. (Author/SKC)

A total of eighty 9-month-old infants were presented with a problem consisting of several different conditions which separated response, position on a table, and absolute spatial position as factors leading to errors in search for hidden objects. (MS)

Three experiments investigated children's typical errors in judging the truth of universally quantified conditional sentences containing "P and not-Q." The error survived on sentences referring to particular things. For second- and fifth-graders, the error survived for nonuniversally quantified conditionals, and for second-graders, the…

Three- and four-year olds were asked to recall their own or another person's actions and to acknowledge the false belief upon which the action was based. They showed excellent recall of inappropriate actions based on a false belief, but failed to use the recalled action as a clue to acknowledge the false belief upon which it was based. (TJQ)

In a study, few subjects accepted empirical evidence of nonconservation of discontinuous quantity and weight. These findings were interpreted as support for the organismic-developmental claim that lower forms of reasoning are transformed into structurally more advanced forms. (Author/ED)

Studied 100 adolescents' approaches to problem-solving proofs and reasoning competence tasks. Found that a formal level of reasoning competence is associated with a deductive approach. Results support the notion of a cognitive development progression from an inductive approach to a deductive approach. (ETB)

Tested with adolescents and adults two predictions from Markovits and Barrouillet's developmental model of conditional reasoning related to the effects of the association between antecedent and consequent terms and the formulation of the minor premise on uncertainty responses. Found results consistent with hypotheses and indicating importance of…

Third- and seventh-grade and college students were tested to assess developmental differences in improvement following contradiction training and to investigate whether improved performance transfers to other conditional reasoning tasks. Results showed age differences: college students improved and transferred performance, seventh graders…

Proposes a new conceptual framework, embedded in a dynamic model, that accounts for children's failure to reason transitively. Examines five different models of transitive reasoning. Develops a model of how children initially represent and then use the ordered information available in the transitive inference model and how these processes change…