Existing models of intertemporal choice normally assume that people are impatient, preferring valuable outcomes sooner rather than later, and that preferences satisfy the formal condition of independence, or separability, which states that the value of a sequence of outcomes equals the sum of the values of its component parts. The authors present empirical results that show both of these assumptions to be false when choices are framed as being between explicitly denned sequences of outcomes. Without a proper sequential context, people may discount isolated outcomes in the conventional manner, but when the sequence context is highlighted, they claim to prefer utility levels that improve over time. The observed violations of additive separability follow, at least in part, from a desire to spread good outcomes evenly over time. Decisions of importance have delayed consequences. The choice of education, work, spending and saving, exercise, diet, as well as the timing of life events, such as schooling, marriage, and childbearing, all produce costs and benefits that endure over time. Therefore, it is not surprising that the problem of choosing between temporally distributed outcomes has attracted attention in a variety of disciplinary settings, including behavioral psychology, social psychology, decision theory, and economics. In spite of this disciplinary diversity, empirical research on intertemporal choice has traditionally had a narrow focus. Until a few years ago, virtually all studies of intertemporal choice were concerned with how people evaluate simple prospects consisting of a single outcome obtained at a point in time. The goal was to estimate equations that express the basic relationship between the atemporal value of an outcome and its value when delayed. Although the estimated functional forms would differ from investigation to investigation , there was general agreement on one point: that delayed outcomes are valued less. In economics, this is referred to as time discounting. Although plausible at first glance, the uniform imposition of positive discounting on all of one's choices has some disturbing and counterintuitive implications. It implies, for instance, that when faced with a decision about how to schedule a set of outcomes, a person should invariably start with the best outcome, followed by the second best outcome, and so on until the worst outcome is reached at the end. Because nothing restricts the generality of this principle, one should find people preferring a declining rather than an increasing standard of living, deteriorating rather than improving health (again, holding lifetime health constant), and so on. In the last few years, several studies have independently fo