Enhanced discrimination (learning to differentiate the various types of problems) is not the only explanation for the interleaving advantage. During interleaved practice, switching among different problem types may strengthen the association between a problem type and its strategy, which promotes successful problem solving. With blocked practice, on the contrary, as all the problems require the same strategy, the student needs only focus on executing a given strategy repeatedly, which might not be as effective in reinforcing the association between a problem type and its strategy