This paper  presents  a  critique  of  expected  utility  theory  as  a  descriptive model  of decision making under risk, and develops an alternative model, called prospect theory. Choices among risky prospects exhibit several pervasive effects that are inconsistent with the basic tenets of  utility  theory. In  particular, people  underweight  outcomes that  are merely  probable  in  comparison  with  outcomes  that  are  obtained  with  certainty. This tendency, called the certainty effect, contributes to risk aversion in choices involving sure gains and to risk seeking in choices involving sure losses. In  addition, people generally discard components that a r e  shared by all prospects under consideration. This tendency, called  the  isolation  effect,  leads  to  inconsistent  preferences  when  the  same  choice  is presented in different forms. An alternative theory of  choice is developed, in which value is  assigned to gains and losses rather than to final assets and in which probabilities are replaced by decision weights. T h e  value function is normally concave for gains, commonly convex for losses, and is generally steeper for losses than for gains. Decision weights are generally  lower than  the corresponding probabilities, except in the range  of  low prob- abilities. Overweighting of  low probabilities may contribute to the attractiveness of  both insurance and gambling. 心理学空间VLACl1?1gS rL[
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http://www.hss.caltech.edu/~camerer/Ec101/ProspectTheory.pdf