Most children under 7 years of age presented with 10 daisies and 2 roses fail to indicate that there are more flowers than daisies. Instead of the appropriate comparison of the relative numerosities of the superordinate class (flowers) to its subordinate class (daisies), they perform a direct perceptual comparison of the extensions of the 2…

Results of two experiments involving 11-, 14-, 17-, or 20-month-old infants indicated that 14-month and older infants did not differentiate the combination of properties that affords containment and that understanding of the causal basis of that function did not begin to emerge until about 17 months. (RH)

Two studies tested college students on the Piagetian water-level task and several crossbar tasks. Performance on a disembedded crossbar task was better than that on the water-level task, regardless of whether the symmetrical nature of the crossbar was emphasized. Men performed better than women. (BC)

Five studies examined adults' responses to weight conservation questions which were constructed to give subjects a choice of two incorrect answers. The results showed that adults (1) acquiesced to the misleading implications of the questions; and (2) exhibited greater nonconservation in response to questions about the body than about external…

Describes Jean Piaget's transformation of society's conception of childhood thought. Emphasizes the enduring contribution to developmental psychology of Piaget's constructivism, his description of developmental mechanisms, his cognitivism, his explication of structural and functional analysis, and his addressing of epistemological issues and…

Examined 2-, 2.5-, and 3-year-olds' reasoning while searching for a ball that had been rolled behind an occluder. Found only 3-year-olds were able to reliably select the correct door; all children could retrieve a toy hidden in the same apparatus if it was hidden from the front by opening a door; and younger children used a variety of strategies.…

Three experiments test object permanenece in 3 1/2- and 4 1/2-month-old infants, and use an impossible-possible-habituation event format. The 4 1/2-month-olds, and the 3 1/2-month-olds who were fast habituators, look reliably longer at the impossible than at the possible event. Results seriously question Piaget's (1954) claims regarding the age at…

Examined object concept development in 2- to 4-year olds with a partial replication of a study by Spelke and Kestenbaum (1986). Found that children judged identical entering and exiting figures as involving one object and different figures as involving two objects. Continuity of movement failed to affect judgments of numerical identity. Findings…

The hypothesis that differences in definitions of perceived internality in Piagetian and locus of control viewpoints account for paradoxical findings was tested empirically using two independent samples of children. Results suggest that perceived internality depends on the aspects of means-ends beliefs on which one focuses.

Administered five Piagetian tests to 180 adolescents for comparison to similar samples from 1967 and 1972. Found that today's adolescents exhibited higher levels of cognitive development than did previous cohorts. Gain varied across tasks, being very large for combinatory thought but mixed for conservation. This acceleration of cognitive…

Three longitudinal studies examined means-ends behavior of 6- to 8-month olds. Found that intentional means-end behavior increased between 6 and 7 months, with 7-month olds' performance influenced by the presence of a toy on the cloth. Performance was the same when cloth was attached to or separate from the toy. By 8 months, infants adjusted…

Attachment representations and self-confidence were assessed at age 7 on the basis of children's responses to a separation story and independent observations, although cognitive functioning was measured at ages 7-17 years based on a battery of Piagetian tasks assessing concrete and formal reasoning. Children with a secure attachment representation…

Study uses two language conditions for evaluating ability in class inclusion. Estimates strategic components of performance on basis of differential consequences of inclusion logic, subclass comparison, and guessing. Results indicate children compare subclasses more frequently with a standard question and guess more frequently with a…

Since early research had shown that a total score on 27 Piagetian tasks was very highly correlated with a Wechsler and achievement composite, a study investigated the possibility of shortening the Piagetian test by means of classical analysis methodology. (HOD)

Three samples of 8- to 16-year olds were assessed three times at yearly intervals on eight water-level items. Within-child change over age was viewed as stochastic process of the child changing or remaining in one of three latent strategy states. Although there was improvement in task performance over age, the general finding was that strategy…