The hypothesis that perceptual development proceeds from less to greater dimensional separability was tested by giving a speeded classification task to first and fourth graders. Results supported the hypothesis that development proceeds toward greater flexibility of attention rather than simply toward increasing separability. (Author/DB)

Investigates effects of perceptual salience and specific orientation values on 16 kindergarten and fourth-grade children executing a speeded sorting task. Kindergarten results supported the cognitive processing prediction that orientation sorting times would vary as a function of condition, but no differences were obtained for the fourth-grade…

The hypothesis that overall-similarity relations structure both adults' and children's classifications of heterogeneous objects (objects that differ in a variety of ways) was supported in two experiments. When objects varied simultaneously on many dimensions, adults and children constructed classifications that maximized within-category similarity…

Children's use of the middle concept was assessed in two developmental studies. Experiment 1, with kindergarten through fifth-grade students, showed marked improvement in the mastery of the middle concept across elementary grades. In Experiment 2, discrimination pretraining with two nonoverlapping stimulus sets transferred to the novel test…

Investigates age differences in selective attention in a coded visual search task where subjects were given different types of information about target location before trial onset. (Author/SS)