Key points are not available for this paper at this time.
Marjorie Henningsen, Mary Kay Stein, Mathematical Tasks and Student Cognition: Classroom-Based Factors That Support and Inhibit High-Level Mathematical Thinking and Reasoning, Journal for Research in Mathematics Education, Vol. 28, No. 5 (Nov., 1997), pp. 524-549
Henningsen et al. (Sat,) studied this question.