Understanding of logical necessity: developmental antecedents and cognitive consequences.

Does abstract reasoning develop naturally, and does instruction contribute to its development? In an attempt to answer these questions, this article specifically focuses on effects of prolonged instruction on the development of abstract deductive reasoning and, more specifically, on the development of understanding of logical necessity. It was hypothesized that instructional emphasis on the metalevel of deduction within a knowledge domain can amplify the development of deductive reasoning both within and across this domain. The article presents 2 studies that examine the development of understanding of logical necessity in algebraic and verbal deductive reasoning. In the first study, algebraic and verbal reasoning tasks were administered to 450 younger and older adolescents selected across different instructional settings in England and in Russia. In the second study, algebraic and verbal reasoning tasks were administered to 287 Russian younger and older adolescents selected across different instructional settings. The results support the hypothesis, indicating that prolonged instruction with an emphasis on the metalevel of algebraic deduction contributes to the development of understanding of logical necessity in both algebraic and verbal deductive reasoning. Findings also suggest that many adolescents do not develop an understanding of logical necessity naturally.