The shift from preoperational thought to operativity entails the idea of necessity. The concrete operativity tasks were analyzed from this perspective. Results from a broad class of conservation training studies were also analyzed from the perspective of their efficacy, fidelity to necessity, and implications for school instruction. (Author/BW)

Three- to 7-year-old children were trained through reinforcement to select the more or less numerous of two rows of squares. All children successfully judged relative numerosity when number covaried with length or density, but only concrete operational children were successful when numbers did not covary with other dimensions. (Author/DB)

Piaget's conservation paradigm was used to assess five- to seven-year-old children's understanding of the permanence of various kinship roles. Children's conservation was studied by applying certain transformations on single- and multiple-kinship role combinations. Kinship conservation developed gradually in this age range. Females' performance…

Thirty mildly retarded children (mean age 9 years) participated in a study in which 24 of the children were trained to a prespecified criterion on one of three logical operations tasks involving length: identity conservation, equivalence conservation, or transitivity. (Author)

Ten retarded children (9 to 14 years old) participated in a training program to help them acquire the ability to conserve number. At the end of the training program, and nine weeks later, a significant number of students in the training group acquired the ability to conserve number. (Author)

Replicates the study by McGarrigle and Donaldson (1975). Considers several objections to McGarrigle and Donaldson's claim that the tasks they used did in fact test the child's ability to conserve number. A procedure free from these objections was employed in a second experiment. Discusses implications for the social psychology of the conservation…

Attractive stimuli and fantasy instructions were used in an attempt to manipulate children's involvement in the outcomes of their number and liquid conservation judgments. (Author/DB)

The study investigated the effects of basic concepts training on conservation acquisition in 41 kindergarten children (17 White boys, 15 White girls, 6 Black girls, and 5 Black boys). Only the conservation training program resulted in significant effects, and that was for the White students alone. (Author)

The "magic" paradigm was devised to assess conservation of number in young children. Subjects were 32 three- to four-year-old children. (MP)

This study examined the relation between number conservation and attention to number, density, and length or area in 86 kindergarteners and 18 third graders. (Author/SB)

This study is an attempt to validate an alternative electronic analog task for the Combination of Chemical Bodies Piagetian task. Both tasks were compared with each other, as well as with a Chemistry Placement Exam and an independent Piagetian measure. Subjects were 55 university first-year chemistry students. (MS)

This study examined language ability in children of the same mental age who differed in their level of cognitive development. Subjects were 68 first-graders, 33 male, 35 female, from a predominantly middle-class elementary school. (Author/SB)

Investigates possible relations between the methods of quantification available to children and their performance on certain tasks requiring an understanding of number invariance. (Author/RK)