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)

In an attempt to accelerate the development of formal operations in average young adolescents, up to 30 intervention lessons relating to all formal schemata were given by science teachers, over a period of 2 years, to classes in eight British schools. Boys starting the program aged 12 years-plus showed a pre-test, post-test effect size on…

Three years after end of 2-year intervention program intended to promote formal operational thinking, achievement of students initially age 11 was tested by their results on British National examinations, taken at age 16 (experimental group n=88, control group n=103). In comparison with control classes, the effect size for science was 0.67,…