Toward an understanding of when prior knowledge helps or hinders learning

Knowledge begets knowledge—or so they say? David Ausubel 1 has famously described prior domain knowledge as the most important determinant of a student’s learning success, “ascertain this and teach him accordingly”. Indeed, prior knowledge—previously learned information organized in a learner’s memory 2 —has long been known to explain large portions of variance in learning outcomes 3 . A new meta-analysis by Simonsmeier et al. 4 suggests that this is not the end of the story, however. By distinguishing learning outcomes from learning gains, the new meta-analysis found that prior knowledge indeed explained large portions of variance in learning outcomes, but it did not—on average—explain variance in learning gains. The former result indicates that those students in a class who know the most at the beginning of a class will likely know the most at the end as well. The latter result is an eye-catching one, as it suggests that knowledge at the beginning of a class does not, in fact, determine how much a student will learn from a particular task or instruction. Does this finding contradict the famous statement by Ausubel? At the very least, as put by Simonsmeier et al., it “calls for systematic research on the conditions under which prior knowledge has positive, negative, or negligible effects on learning” 4 . I wholeheartedly agree that this is of outmost importance for both theory construction and educational practice, and I applaud the authors of the meta-analysis for bringing this topic to the fore. The goal of this brief commentary is to provide initial pointers for systematic research on the factors that determine whether and how prior knowledge affects learning.