Generally, the process involves cognitive changes, such as shifting values, goals, attention and interpretation of a situation. Hedonic adaptation can occur in a variety of ways. The process of hedonic adaptation is often conceptualized as a treadmill, since no matter how hard one tries to gain an increase in happiness, one will remain in the same place. Generally, hedonic adaptation involves a happiness "set point", whereby humans generally maintain a constant level of happiness throughout their lives, despite events that occur in their environment. Hedonic adaptation is a process or mechanism that reduces the affective impact of emotional events.