Many people who have Parkinson’s can’t walk because of their tremors. However, one man discovered a solution to this problem by placing small obstacles before his feet and stepping over them. Using the small goal of stepping over an object, the man learned to walk again. This tactic worked for thousands of other Parkinson’s patients as well. Goals, Alter suggests, motivate people to action. This principle is also visible when looking at the finishing times of marathon runners. A graph plotting the times of nearly 10 million marathon runners shows that many more athletes finish near numerical milestones such as three and a half hours or four hours, than they do at times just after such milestones.

Reaching a goal does not necessarily make a person content, though. Alter tells the story of Robert Beamon, a man who broke the world record in the long jump in the 1968 Mexico City Olympics by almost two feet. His jump had been so far beyond what was expected that the officials did not have measuring equipment on hand to accurately measure the jump. Beamon won the gold medal and the jump remained the world record for almost 23 years. Yet Beamon remembers his celebration only lasting a few minutes and shortly after wondering what he would next do with his life.