A STUDY ON THE EFFECTIVENESS OF INTERVENTION METHODOLOGY ON THE COGNITIVE DEVELOPMENT OF SCIENCE STUDENTS

The study was conducted to ascertain the effect of intervention methodology as envisaged by the CASE project (Adey, Shayer and Yates 1989, Shayer and Adey 1992 a, 1992b) on cognitive development of science students in secondary schools of Pakistan. Using a pry-test post-test control 'group design, a total of 32 intervention lessons were delivered to the experimental subjects over a period of about two and a half years. Subjects were selected from four different schools of Lahore, particularly , those which were near to the work place of the researcher. Teachers taking part in the study were imparted In-Service training to deliver intervention lessons within the parameters described by Piaget and Vygotsky, and explained in Thinking Science material. A Piagetian pre-test was used to determine the cognitive level of control and experimental subjects at the beginning of intervention. Manx of the control group subjects were' at relatively higher cognitive levels' compared with their experimental subjects. At the end of intervention, a Piagetian post-test was administered to control and experimental subjects to ascertain any difference in their cognitive levels. Mean post-test gain of experimental and control groups were compared to see the significance of difference between their performance. The impact of intervention was assessed in terms of the effect-size, which is the difference between gain of experimental and control groups divided by the SD of the control groups. Pooled SD of the pre-tests and post-tests of the control groups were used to calculate the effect-size. After analyzing the results. it was found that over a period of two and a half years , intervention has substantially affected the cognitive growth of experimental subjects. It was further found that experimental subjects performed better than their respective controls on achievement tests in science and mathematics. To measure the effect of intervention on achievement tests. Results of cognitive pre-test were used to predict, their subsequent performance in school subjects. Residualised gain scores so obtained. show that experimental subjects performed better than their controls on achievement tests in science and mathematics. It is believed that the increased cognitive capacity of experimental subjects was responsible far their improved achievement in science and , mathematics