The learner’s prior experience determines how (s) he builds on the information imparted next because ’known to unknown’ linkage facilitates retention and, thus, is highly related to the effectiveness of teaching. As one learns from parents and peers, parents’ education and peer groups also influence the level and quality of learning; and, as family size determines the availability of resources, it also plays a role. However, none of these is as highly related to the effectiveness of teaching.