Originally published in 1970 The Effects of Structural Relations on Transfer follows on from the investigation reported in the first volume Thinking in Structures . It deals with four problems: How far is it true that learning is accelerated by tackling the more difficult tasks first? Do learning situations largely under the learner's control increase ability to learn large mathematical groups? Does Structural learning take over from Stimulus/Response Association learning as the material becomes more complex? Are there age-differences in the amount of difficulty experienced with material taken in different orders? Some valuable answers are elicited, and the results are considered for their implication in actual classroom practice. Today it can be read in its historical context.