Howard C. Kunreuther
The Wharton School
University of Pennsylvania
"And do you, like a skillful weigher, put into the balance the pleasures and the pains, and their nearness and distance, and weigh them, and then say which outweighs the other...." (Jowett translation)This view is central to Plato's thought, underlying his theories of education and government. Studies in mathematics, science, and metaphysics are needed to educate the "skillful weigher", who must integrate across different goals and across near and distant times. Similar views dominated utilitarian thought in the 17th to 19th centuries, and included integration of value across individuals in a society as well as different goals and times. (e.g., Bentham, 1789). Aristotle's Ethics, by contrast, partially disagreed, emphasizing multiple goods, and stating that the way in which different goals fit together should vary with the occasion. Aristotle can perhaps be read as advocating situation-dependent integration of multiple goals, an idea that we pursue and elaborate in this paper. Despite this hint from Aristotle, Plato's concept of a single common currency that serves to integrate value across myriad goals has largely held sway both in general psychology and in decision science. Freud's concept of libido (1920), Beebe-Center's hedonic tone (1932), Hull's concept of generalized drive (1951), work on reward systems in the brain (Olds & Milner, 1954; Wise, 2004), and Diener's and Seligman's concepts of general happiness (e.g., Diener & Seligman, 2002) all suggest some general quality that is linked to many different goals. An exception is Keeney (1992), who advocates that decision analysis focus on separate goals and values as a starting point, rather than on goal tradeoffs as represented by overall utility. In decision science, the concept of maximization is linked closely to a mapping onto a single dimension of utility. A bounded set of real numbers has a limiting maximum; but there is no natural total ordering of sets of vectors in two or more dimensions, and therefore no natural concept of maximization. In fact, total ordering is fundamental to most foundational theories in decision science (Savage, 1954; Krantz, Luce, Suppes & Tversky, 1971; Kahneman & Tversky, 1979; Tversky & Kahneman, 1992). The idea that all human goods can be weighed in the same balance is a fascinating scientific hypothesis that has been worth pursuing, to determine the extent of its applicability and the ways in which it fails. Translating many goods into a one-dimensional currency fits well with human thought processes, especially analog mental models (Attneave, 1974; Egan & Grimes-Farrow, 1982). Unidimensionality opens the way to the application of powerful mathematical methods for computing or for approximating maxima (Gregory & Lin, 1992; Nocedal & Wright, 2006).
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| Possible events | ||||||||
| (mutually exclusive and exhaustive) | ||||||||
| (r)2-5 Possible strategies | E1 | E2 | ... | En | ||||
| strategy 1 | o11 | o12 | ... | o1n | ||||
| strategy 2 | o21 | o22 | ... | o2n | ||||
| ... | ... | ... | ... | ... | ||||
| strategy m | om1 | om2 | ... | omn | ||||
| Outcomes have subjective values uij = value(oij). | ||||||||
| uij may be integrated across multiple attributes of oij. | ||||||||
Multi-attribute utility is integrated
across uncertain events:
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| Active goals | ||||
| Possible plans | G1 | G2 | ... | Gn |
| plan 1 | w11 | w12 | ... | w1n |
| plan 2 | w21 | w22 | ... | w2n |
| ... | ... | ... | ... | ... |
| plan m | wm1 | wm2 | ... | wmn |
| Plans have decision weights for each goal: wij=w(Gj | plan i) | ||||
| Plan i is evaluated in terms of the vj and wij. | ||||
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| Events | ||||
| E1 | E2 | E3 | E4 | |
| event description | no flood | flood causes | damaging | destructive |
| little damage | flood | flood | ||
| event probability | .85 | .09 | .04 | .02 |
| Outcome components | ||||
| financial cost | premium | premium | premium | premium |
| hassles | none | minor | major | great |
| chronic flood-related anxiety | none | none | none | none |
| acute anxiety (at flood) | none | little | little | little |
| other feelings | regret | justification | justification | justification |
| Outcome components | ||||
| financial cost | none | small | large | catastrophic |
| hassles | none | minor | major | great |
| chronic flood-related anxiety | some | some | some | some |
| acute anxiety (at flood) | none | much | much | much |
| other feelings | justification | relief | major regret | vast regret |
| Goals | ||||||||
| feel | avoid | avoid | avoid | avoid | avoid | avoid | avoid | |
| justified | small | major | catastrophic | chronic | acute | major | vast | |
| Plans | loss | loss | loss | anxiety | anxiety | regret | regret | |
| Plan 1: Purchase flood insurance | .15 | 0 | 1 | 1 | 1 | mostly | 1 | 1 |
| Plan 2: No insurance | .85 | .85 | .94 | .98 | 0 | .85 | .94 | .98 |
| Goals | |||
| Insurance plans | Avoid catastrophc loss | Avoid regretting a modest loss | Minimize up-front costs |
| A | excellent (high limit) | OK | poor (expensive) |
| B | OK | poor (high deductible) | excellent (cheap) |
| C | poor (low limit) | excellent (low deductible) | OK |
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| (2) |
| (3) |
| (4) |
| (5) |
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