Freud’s second plastic idea was that of the psychological critical period and the related idea of sexual plasticity. As we saw in chapter 4, “Acquiring Tastes and Loves,” Freud was the first to argue that human sexuality and the ability to love have critical periods in early childhood that he called “phases of organization.” What happens during these critical periods has an inordinate effect on our ability to love and relate later in life. If something goes awry, it is possible to make changes later in life, but plastic change is much harder to achieve after a critical period closes.
