Attempts to show that not only can density be taught to lower ability pupils but that by doing so, there is the possibility of assisting pupils to develop their reasoning powers. Lists teaching activities that help in this process. (CW)

The effect of intervention lessons designed to accelerate the development of formal operations taught over a period of two years to adolescents was assessed. Results indicated that the experimental group had achieved a significantly greater gain in cognitive levels than the control group. Implications are discussed. (CW)

To test whether gains in cognitive development can be accelerated, an intervention model was used to give pupils special lessons in science, using ideas of cognitive conflict, metacognition, and bridging in the context of formal operations. Found that intervention led to substantial and long-lasting increased achievement in science, mathematics,…