The previous themes reach into modern debates about freedom and necessity, which are still central in education and psychology today. Contributing to the rise of formal disciplines of developmental and child psychology, educational psychology, clinical psychology and cognitive psychology, as well as psychiatry, empirical approaches based on sense perception began in the mid-eighteenth century; but they are equally the outcome of broader religious and cultural influences. The book therefore concludes with an overview of the direct traces on the modern disciplines of the religious ideas discussed in earlier chapters: in Britain through David Hartley, Joseph Priestley and Francis Galton, and the nature-versus-nurture formula; and in France Hippolyte Taine, Alfred Binet (creator of the ‘mental age’ score, subsequently IQ measurement) and Jean Piaget himself.

In this chapter, we argue that to understand intelligence one must understand motivation. In the past, intelligence was often cast as an entity unto itself, relatively unaffected by motivation. In our chapter, we spell out how motivational factors determine (1) whether individuals initiate goals relating to the acquisition and display of intellectual skills, (2) how persistently they pursue those goals, and (3) how effectively they pursue those goals, that is, how effectively they learn and perform in the intellectual arena. As will be seen, motivational factors can have systematic and meaningful effects on intellectual ability, performance, and accomplishment over time. Our discussion emphasizes that heritability is not incompatible with the malleability of intelligence and that motivation is the vehicle through which intellectual skills are successfully acquired, expressed, and built upon.