A variety of types of evidence attest to the importance of such explanatory activities. For both adults and children, students who ask themselves more questions about the meaning of a textbook as they are reading it learn more from their reading than do children who read without asking many questions. This has been shown for learning of both physics and computer programming (Chi et al., 1989; Pirolli & Recker, 1994). The quality as well as the quantity of explanations that children generate while reading is related to their learning. For example, when the best learners study example problems, they are especially likely to connect particular aspects of the examples to particular statements in the text (Pirolli & Bielaczyc, 1989).