Psychology and Savings Policies
指出美国个人储蓄率低的问题，认为生命周期储蓄理论存在缺陷，需融入心理学因素以改进理论并提出有效政策建议。
Many observers of the current economic scene are concerned about the low rate of personal saving in the United States. One well-known researcher, Laurence Kotlikoff (1992), calls the situation a crisis. He proposes that each American worker receive an annual statement from the Social Security Administration with projected benefits upon retirement, arguing that: each of us got [this statement] our attention would be caught and perhaps our of saving, which is in such urgent need of redress, would really change (p. 107). I agree with the thrust of Kotlikoff's recommendations, and join him in applauding steps that will alter the general public's of However, as economists, we need to recognize that the economic theory of saving is similarly in urgent need of redress. If we are to understand why people are saving so little and are to make helpful recommendations as to how to get people to save more, we have to incorporate more of the of saving into our economic theories. Kotlikoff's policy proposal, while a sensible one, highlights the growing gap between theory and policy prescription in this domain. If households are acting in accordance with the life-cycle theory of saving, then undersaving is impossible, so why do they need to have their psychology redressed? And, how does this psychology fit into the model? This example reflects an increasing frustration in the economics community about personal saving. Many observers have come to the conclusion that the low saving rate represents an important problem on two fronts: macroeconomists worry that the low saving rate will produce too little investment, and microeconomists worry that individuals, particularly the baby boomers, are not putting enough away to finance a satisfactory lifestyle in retirement. These are serious concerns. However, the frustration comes from the realization that, even if there was agreement that the saving rate needs to go up, economic theory offers little help in constructing a solution. In the standard life-cycle framework the only policy variable is the after-tax rate of return to saving. Yet it is well known that the theory does not specify the sign of the relationship between the saving rate and the interest rate. Raising the interest rate increases the returns to saving but decreases the amount of saving necessary to yield any given future consumption level. Furthermore, empirical estimates offer little help. Most studies are unable to reject the hypothesis that the elasticity of personal saving with respect to the interest rate is zero. Clearly this is frustrating: the theory only gives us one lever to use, and we don't know whether to push or pull! With this background, I wish to supply what should be considered good news: the theory is misspecified. Life-cycle models of saving fail to describe actual household saving in three important ways. This failure of the theory is good news because by incorporating some basic we can enrich the theory and generate specific policy recommendations. In this paper I will begin by characterizing the problems with the theory and then go on to discussing the implications of modifying the theory.