| Abstract: | Three years after the end of a two-year intervention program intended to promote formal operational thinking, the achievement of students initially 11 years of age was tested by their results in British National examinations, taken at age 16. Although the intervention was set within the context of science learning, the effects were found in science, mathematics, and English. In contrast to results reported earlier for the older cohort aged 12 years initially, where the boys showed greater achievement than girls in science and mathematics, here the effect was limited to girls. In comparison with control classes the effect sizes were science, 0.67σ mathematics, 0.72σ, and English, 0.69σ. Although half of the students showed increased achievement in science, which was consistent with the Piagetian model used in the intervention, the achievement of some in science, mathematics, and English was not associated with gains on Piagetian tests above those of control students. These results were attributed to aspects of the intervention methodology intended to enhance metacognition. The distinction between intervention and instruction was discussed in relation to normative data on Piagetian development in adolescents. |
