Retention of problem solutions: the re-solution effect.

Four experiments compared the re-solution performance of prior solvers with that of prior nonsolvers given the correct solutions. Experiments 1 and 2 challenged Weisberg and Alba's (1981) contention that solving a problem and being shown the solution yield equivalent problem knowledge. In both experiments, students who initially solved problems showed near-perfect recall of the solutions after a 1-week delay, far superior to recall by students who had been shown the correct answers. In Experiment 3, solves showed poor solution retention when the connection between the problem and the solution was not meaningful. Experiment 4 showed that with meaningful problems, solvers and those merely provided with solutions have qualitatively different problem representations. The findings can be explained in terms of differential understanding of problems and their solutions.

Stimulation and control as components of stereotyped body rocking.

Severely and profoundly mentally retarded children who engaged in stereotyped body rocking were presented with all possible pairs of three conditions and made a choice as to which they preferred: a rocking chair that rocked freely under the child's control (active stimulation), a rocking chair that provided the same stimulation but was under the experimenter's control (passive stimulation), and a rocking chair that had been immobilized (stationary). Children significantly chose the active stimulation condition over the passive and the passive over the stationary; however, the degree of the effect was associated with developmental level. Results were interpreted as showing that self-stimulation involves at least two independent processes, control and stimulation.