Summary. According to Piaget, cognitive development is characterised by the simultaneous and concurrent emergence of constructs that require the same underlying intellectual processes. Such syncronies in development—structure d'ensemble in Piaget's terms—are a fundamental feature of his stage theory. In the present study, the structural features of sensorimotor intelligence were assessed among three groups of retarded infants and toddlers administered the seven Uzgiris and Hunt Piagetian based scales. Hierarchical cluster analysis (HCA)—a procedure designed to partition variables into optimally homogeneous groups—was performed on two measures of relationship (stage congruence and intercorrelations) among the responses of the subjects on these scales to determine the methodological utility of the statistical procedure. The results proved positive, and yielded information useful for discerning the unique patterns of organisation of sensorimotor intelligence among the three groups of children. The potential utility of HCA as an analytical technique for studying Piaget's structure d'ensemble stage criteria is illustrated.

Sixteen black and white inner-city public school teachers who were trained to use positive behavior contingencies did so for one academic year with a total of 730 Afro-American disadvautaged pupils from the first through the eighth grades. Compared with matched control teachers and classes, these 16 teachers showed higher incidences of positive reinforcement and lower incidences of punishment. The experimental classes were less disruptive and more on task. They gained more in both IQ and school achievement. Inner-city teachers can be trained to employ positive techniques of behavior management; they like and use such training; and public school pupils profit dramatically from restructuring their learning environment. 1 This study was conducted under the auspices of the Georgia Department of Education, which provided funds allocated under Title III, Public Law 89-10. Readers will note that incredible amounts of effort and goodwill on the parts of many were necessary for this study to be conducted. The Project staff, the teachers involved in the classrooms, and the principals of the different schools deserve at least as much credit as the authors. Thanks should also be extended to all the children and youth who took part.2 Requests for reprints should be sent to Howard A. Rollins

Studies of the application of behavior modification to the classroom rarely report the failure rate or the degree of success relative to appropriate control groups. In the present study, fourteen teachers were trained to use a contingency management program emphasizing the reinforcement of appropriate conduct while minimizing attention to inappropriate conduct. Changes in teacher and student behaviors from a three week baseline period to a three week period following program implementation were compared with changes in control classes over the same period. Twelve of fourteen experimental classrooms improved dramatically as a result of the program with fewer disruptions and higher task involvement. There were no reliable changes in control classes. These data indicate that contingency management works extremely well for many teachers.

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