Nine experiments examined 6- to 10-month-olds' formation of an abstract category representation for "between." Findings indicated that older, but not younger infants, could form an abstract category representation for "between" when performing in an object-variation version of the between categorization task. Six- to…

Students from the fifth, eighth, and eleventh grades were asked to describe their ideal self-image. Analyzed according to 19 categories (such as occupation, marriage, and physical appearance), the responses revealed differences according to gender, age, cognitive-developmental level, and socialization experience. (DM)

Analyzed genetic and environmental contributions to intellectual change in 258 adopted and 93 biological children of 3-14 years. The effect of genes and family environment was significant at the time of the first measurement, but only genes made an additional contribution between the first and the second. (RJC)

Children were asked whether someone would get sick from drinking juice placed near a bug. Some preschoolers and most seven- and eight-year olds recognized the need for physical contact with the bug to make the juice noxious, whereas some believed the mere presence of a contaminant made it noxious. Thus, associational contamination sometimes plays…

Two studies examined the progress in normally developing preschoolers' ability to produce actions with imagined objects (pantomimes). Found that young children not only had difficulty producing imaginary object representations in contrast to normal adults, they also had difficulty comprehending imaginary object representations and were better at…

Children between 7 and 13 years of age were presented with scenarios for which they predicted a result derived from 2 or 3 interacting variables. The effect of the interaction of variables was observed for all ages in familiar scenarios, but the effect diminished in scenarios of unfamiliar activity. (BC)

Asked 30 children aged 4 years and 30 children aged 6 years to explain what they found funny in 2 humorous pictures. Results indicated that the older children explained humor differently than the younger children and that boys recognized the humor of the visual images more easily than did girls. (MDM)

Two studies examined the relationship between cognitive rigidity and cognitive inertia, with a total of 52 children and adults with mental retardation and 50 nonretarded individuals. Findings provide some support for the theory that there are age-related inherent structural differences leading to greater rigidity in older adults. (DB)

Four studies assessed whether children and adults saw categorization decisions as objective matters of fact or as invented conventions. Found that preschoolers treated basic-level animal and human-made artifact category decisions as objective, with kinds of animals treated as more objective than kinds of artifacts. Adults' judgments were similar…

Four experiments and an analysis of pooled data from English and Japanese children show a linear increase in understanding false beliefs with number of older siblings; no such effect for children younger than 38 months; no helpful effect of younger siblings at any age; no effect of siblings' gender; and no helpful effect of siblings on a source…

Examined relationship between children's ability to infer the veracity of an adult's statement and the adult's informedness. Found that children tended to believe utterances from speakers who were better informed than they themselves were and to disbelieve less well-informed speakers, with no age-related differences. Children gave explicit…

Two studies tested the hunter-gatherer theory predicting that females should have better incidental memory for objects and locations than males. Subjects were 3- to 6-year olds and adults. Results indicated that females and males remembered more toys or objects congruent with their own sex but that there was no overall advantage for females.…

Adult and 10- and 12-month olds participated in two experiments to determine reliance of infants on object-kind information in solving problems of object individuation. Findings converge with those of object-first hypothesis of developmental course of object individuation. Findings suggest that young infants may represent one concept as criteria…

Two experiments examined development of economic understanding among 5-, 7- and 9-year-olds. Found that most 5-year-olds understood the goal of acquiring desired goods, and most 7- and 9-year-olds also understood the goals of seeking profits, acquiring goods inexpensively, and competing successfully with other sellers. Results suggest that older…

Five experiments examined matching to sample procedures among preschoolers. Results indicated that children selected taxonomic comparisons more often than thematic comparisons, independent of age, gender, instructions, order of trial type, specificity of feedback, presence of unrelated third comparisons, and level of taxonomy. Instructions to…