The book’s primary theme is the psychological consequences of inequality. Payne states early on that he is not necessarily interested in what first caused inequality (although he touches on this) but rather how inequality shapes our thought processes and decision-making. His primary thesis is that inequality affects us all in a systematic and predictable way, and that inequality, not poverty, is what matters most. In short, Payne is most concerned with inequality’s effects on humans.

Payne tackles this theme throughout the empirical chapters that comprise the bulk of the book. He shows that inequality causes people to engage in riskier behavior because feeling poor makes humans place extreme focus on the present at the cost of the future. This leads to self-defeating behavior because instead of planning for the future, the poor are constantly dealing with crises of the present, which traps them in poverty. Similarly, inequality also pushes us further to the left or the right, and we become less likely to compromise in our political positions. This is because people vote for policies and parties they feel are in their self-interest, and inequality changes our perception of what is or isn’t in our self-interest. As inequality grows, we grow further and further apart from each other and, because we believe that we see the world objectively, we become more likely to see those who disagree with us as idiots.