The paper examines the influence of individual heterogeneity to the efficiency of collective action under the analytic framework of Cournot-Nash equilibrium.

It ignores students individual differences and has suppressed the potential display.

This study, involving a sample of 1993 subjects of 10 t o 90 years of a ge and a battery of computer tests of processing speed, working memory, mental a rithmetic, spatial representation and memory recognition, was conducted to analy se the cognitive developmental course across the life span, the changes of cogni tive separability and individual difference.