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American Economic Review


As the workhorse of consumption and saving research for the past four decades, the life-cycle model has proved flexible and useful for exam- ining a variety of questions. In a classic paper, Albert Ando and Franco Modigliani (1963 p. 56) stated a key assumption of the basic model: “[t]he individual neither expects to receive nor desires to leave any inheritance.” Although the authors contended that the absence of a bequest motive was not critical to the heart of their results, the assumption set off a long-standing battle over the relative importance of different motives for saving. In an influential study, Laurence Kotlikoff and Laurence Summers (1981) estimated that a large fraction of the U.S. capital stock was attributable to intergenera- tional transfers. Modigliani and his collabora- tors vigorously disagreed and, based on their own empirical work, claimed that life-cycle saving was the primary source of capital accu- mulation (Modigliani, 1988). Subsequent work has failed to reach a consensus. 1 Since this debate began, an important ad- vance in the consumption literature has been the incorporation of uncertainty in life-cycle models (see e.g., R. Glenn Hubbard et al., 1995). We argue that allowing for uncertainty resolves the controversy over the importance of life-cycle and bequest saving by showing that these motives for saving are overlapping and cannot generally be distinguished. A dol- lar saved today simultaneously serves both a precautionary life-cycle function (guarding against future contingencies such as health shocks or other emergencies) and a bequest function because, in the likely event that the dollar is not absorbed by these contingencies, it will be available to bequeath to children or other worthy causes. Under this view, households have a bequest motive, but bequests are given (i.e., the motive is “operative”) in only some states of the world. 2 Wealth is something like traveler’s checks: you take them along on va- cation “just in case,” but odds are they will remain uncashed and available for sundry goods after the journey is complete. We first demon- strate the result using a simple model and then argue that this approach reconciles the apparent importance of bequests with households’ de- clared focus on life-cycle saving. Finally, we consider implications of our analysis.

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