Humans have limited time and brainpower. As a result, they use simple rules of thumb—heuristics—to help them make judgments. An example would be “availability.” Suppose I ask you if Dhruv is a common name.

The planner, in contrast, is completely altruistic. All she¶ cares about is the utility of the series of doers.

One solution to this problem is to aggregate investments into a pool where they can be considered as a package.

Our model is really based on a metaphor. We propose that at any point in time an individual consists of two selves. There is a forward-looking “planner” who has good intentions and cares about the future, and a devil-may-care “doer” who lives for the present.

rejected this idea because we did not think that the doer engages in strategic behavior; he is more of a passive creature who simply lives for the moment. He reacts to what is in front of him and consumes until sated.

“choice architecture” to describe what we were trying to do. In curious ways, simply having that phrase to organize our thoughts helped us create a checklist of principles for good choice architecture, with many of the ideas borrowed from the human design literature. Designing good public policies has a lot in common with designing any consumer

Unlike the sick girl, the typical domestic public policy decision is abstract. It lacks emotional impact.

The second asks how much cash you would demand to increase the risk of dying by the same amount.

losses are roughly twice as painful as gains are pleasurable, a finding that has been replicated numerous times over the years.