Seven rhesus monkeys reared on diets high in phenylalanine to induce phenylketonuria (PKU--a metabolic disorder associated with mental retardation if untreated) were compared with normal, pair-fed, and younger controls; frontal brain-lesioned monkeys; and those raised on high-tryptophan diets in three object discrimination tasks. (Author)

This study was concerned with the effect of situational frequency manipulations on subsequent discrimination learning. The subjects were 104 fourth-grade children attending two elementary schools located in middle-class residential areas. Twenty-six subjects were randomly assigned to each of two picture conditions. The other 52 subjects were…

Eighty-four nine year old children, twelve in each of seven experimental groups, learned a two-choice successive discrimination problem. The parameters that were systematically manipulated included: (1) immediate versus delayed reinforcement; and (2) forced preresponse stimulus exposure versus stimulus exposure during the delay interval,…

The author initially cites the associationistic position of Spiker and the perceptual learning position of E. Gibson and concludes that the existing data does not clearly support either hypothesis. He describes a new approach designed to test these explanations of the role of verbal pretraining on subsequent discrimination learning. It consists of…

The study focuses on the possibility that the tendency of academic underachievers to respond in terms of all inclusive language is indicative of their incapacity to discriminate the uniquely meaningful aspects of their environment. The authors hypothesize that academic achievers would differ significantly from academic underachievers in their…

Simple and complex learning and problem solving situations were employed with mentally retarded children and adults. In the Rotation-Discrimination Complex and the Size-Discrimination Simple experiments, upper and lower test achievement subgroups were subjected to two basic types of visual discrimination at different levels of task complexity.…

Written from a developmental viewpoint, this book for parents and teachers presents both a theoretical orientation and perceptual motor activities for training children with learning disabilities, both the brain injured and the retarded. The theoretical basis for training generalized motor responses is considered in terms of motor perceptual…

THE CONTRIBUTIONS OF 21 AUTHORS IN THIS VOLUME ARE DEVOTED TO ASSESSING THE STATUS OF RESEARCH AND THEORY IN MENTAL DEFICIENCY, FOCUSING ATTENTION ON THE BEHAVIOR OF THE MENTALLY HANDICAPPED. PART ONE IS CONCERNED WITH RESEARCH FINDINGS AND THEORIES TO EXPLAIN MENTAL DEFICIENCY. COMPREHENSIVE PSYCHOLOGICAL THEORIES REPRESENTED INCLUDE FIELD…