David C. Geary's thesis has the potential to alter our understanding of those aspects of human cognition relevant to instruction. His distinction between biologically primary knowledge that we have evolved to acquire and biologically secondary knowledge that is culturally important, taught in educational institutions and which we have not evolved…

In this reply to commentaries on the Kirschner, Sweller, and Clark (2006) paper, we not only reemphasize the importance of randomized, controlled experimental tests of competing instructional procedures, but also indicate that altering one variable at a time is an essential feature of a properly controlled experiment. Furthermore, we also…

Evidence for the superiority of guided instruction is explained in the context of our knowledge of human cognitive architecture, expert-novice differences, and cognitive load. Although unguided or minimally guided instructional approaches are very popular and intuitively appealing, the point is made that these approaches ignore both the structures…