This is the last chapter of Part I. It illustrates the explanatory power of the findings thus far by applying them to a well-known puzzle: Why is it that poor people so often seem to lack the willpower and discipline to improve their life circumstances? Sometimes this is explained by reference to a “culture of poverty,” but this explanation is highly controversial. This chapter provides a fresh take on this contentious issue by showing that, irrespective of the sociology, there certainly exists a psychology of poverty. Based on a wide range of data, I show that poverty is correlated with a higher incidence of all the factors undermining self-control discussed in the preceding chapters. I also show that children who grow up in poverty more often experience the circumstances that hamper the development of self-control, while adults who live in poverty more often experience the situational conditions that hinder the successful exercise of self-control. The upshot is that punishing the poor for undisciplined behavior – say by cutting their welfare – may well be counterproductive.