Two experiments which investigated the young child's ability to deal with multiplicative classes and relations (considered behavioral indices of concrete operations thought) in double series and cross class matrices are described and discussed. In the initial study, 160 children from preschool through grade 2 received six matrix subtasks…

The Perry Preschool Project assessed longitudinal effects of a 2-year program consisting of a daily 3-hour cognitively oriented nursery, a weekly 90-minute home visit, and less frequent group meetings of the pupils' parents. Subjects consisted of 3- and 4-year-old Negro disadvantaged and functionally retarded children, whose pretest scores on the…

Kindergarten, second-grade, fifth-grade, and college subjects were tested in a serial-position recall task under each of four conditions: Visual stimuli/visual recall cue, visual stimuli/auditory recall cue, auditory stimuli/visual recall cue, auditory stimuli/auditory recall cue. Visual stimuli were pictures of common animals and objects;…