Social choice theory

Social choice theory is a theoretical framework for measuring individual interests, values, or welfares as an aggregate towards collective decision. A non-theoretical example of a collective decision is passing a set of laws under a constitution. Social choice theory dates from Condorcet's formulation of the voting paradox. Kenneth Arrow's Social Choice and Individual Values (1951) and the Arrow's impossibility theorem are generally acknowledged as the basis of the modern social choice theory.

Social choice theory blends elements of welfare economics and voting theory. It is methodologically individualistic, in that it aggregates preferences and behaviors of individual members of society. A characteristic approach proceeds from a set of reasonable axioms of social choice to a social welfare function (or constitution). Many earlier results uncover the logical incompatibility of various axioms and, having revealed thus the aggregation problem, suggest reformulation or theoretical triage in dropping some axiom(s).

Social choice theory and public choice theory may overlap but are disjoint if narrowly construed. The JEL classification codes places Social Choice into JEL D71 (with Clubs, Committees, and Associations) whereas most Public Choice subcategories are in JEL D72 (Economic Models of Political Processes: Rent-Seeking, Elections, Legislatures, and Voting Behavior).

Interpersonal utility comparison

Following Jeremy Bentham, utilitarians have argued that preferences and utility functions of individuals are inter-personally comparable and may therefore be added to arrive at a measure of aggregate utility. Utilitarian ethics call for maximizing this aggregate.

Lionel Robbins questioned whether mental states, and utilities they reflect, can be measured and, a fortiori, interpersonal comparisons of utility as well as the social choice theory on which it is based. Consider for instance the law of diminishing marginal utility, according to which utility of an added quantity of a good decreases with the amount of the good that is already in possession of the individual. It has been used to defend transfers of wealth from the ``rich to the ``poor on the premise that the former do not derive as much utility as the latter from an extra unit of income. In an essay (1935, pp. 138–40), Robbins argued that this notion is beyond positive science; that is, one cannot measure changes in the utility of someone else, nor is it required by positive theory.

Apologists of the interpersonal comparison of utility (ICU)have argued that Robbins claimed too much. John Harsanyi agrees that full comparability of mental states such as utility is never possible but believes, however, that human beings are able to make some interpersonal comparisons of utility because they share some common backgrounds, cultural experiences, etc. In the example from Amartya Sen (1970, p. 99), it should be possible to say that Emperor Nero's gain from burning Rome was outweighed by the loss incurred by the rest of the Romans. Harsanyi and Sen thus argue that at least partial comparability of utility is possible, and social-choice theory proceeds under that assumption.

Sen proposes, however, that comparability need not be partial. Kenneth Arrow's famous impossibility result spelled the second end to social choice theory, by proving the inconsistency of social preferences even when held to rather minimal standards such as non-dictatorship and Pareto optimality. Under partial comparability, this result becomes less restrictive. Sen's theory of informational broadening does away with the rest. Sen believes that even complete ICU would lead to socially suboptimal choices because mental states are malleable. A starving peasant may have a particularly sunny disposition and thereby derive high utility from a small income. This fact should not nullify, however, his claim to compensation or equality in the realm of social choice.

Social decisions should accordingly be based on immalleable factors. Sen proposes interpersonal comparisons based on a wide range of data. His theory is concerned with access to advantage, viewed as an individual's access to goods that satisfy basic needs (e.g., food), freedoms (in the labor market, for instance), and capabilities. We can proceed to make social choices based on real variables, and thereby address actual position, and access to advantage. Most importantly, Sen's method of informational broadening allows social choice theory to escape both the objections of Arrow and Robbins, which looked as though they would permanently harm social choice theory.

See also

Part of a series on
Utilitarianism
Predecessors Epicurus David Hume · Claude Adrien Helvétius · William Godwin · Francis Hutcheson
People Jeremy Bentham · John Stuart Mill Henry Sidgwick · Richard Mervyn Hare · Peter Singer
Types of utilitarianism Preference · Rule · Act Two-level · Total · Average Relative · Negative · Hedonism Enlightened self-interest
Key concepts Pain · Suffering · Pleasure Utility · Happiness · Eudaimonia Consequentialism · Felicific calculus
Problems Mere addition paradox Paradox of hedonism Utility monster
Related topics Rational choice theory · Game theory Social choice · Neoclassical economics
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• Arrow's impossibility theorem
• Capability approach
• Compensation principle
• Extended sympathy
• Gibbard–Satterthwaite theorem
• Justice (economics)
• Liberal paradox
• Mechanism design
• Nakamura number
• Rule according to higher law
• Relative Utilitarianism
• Voting system

References

• Kenneth J. Arrow, 1951, 2nd ed., 1963, Social Choice and Individual Values. ISBN 0-300-01364-7
• _____, 1972, Link to text of Nobel lecture with Section 8 on the theory and background.
• _____, 1983, Collected Papers, v. 1, Social Choice and Justice ISBN 0-674-13760-4
• Kenneth J. Arrow, Amartya K. Sen, and Kotaro Suzumura, ed., 1997, Social Choice Re-Examined, 2 vol. ISBN 0-312-12739-1 & ISBN 0-312-12741-3
• _____, ed., 2002, Handbook of Social Choice and Welfare. Vol. 1, ch. abstracts.
• Walter Bossert and John A. Weymark, 2008. "social choice (new developments)," The New Palgrave Dictionary of Economics, 2nd Edition, Abstract.
• Allan M. Feldman and Roberto Serrano, 2006. Welfare Economics and Social Choice Theory, 2nd ed. ISBN 0387293671, ISBN 9780387293677 Arrow-serachable chapter previews.
• Gaertner, Wulf (2006). A primer in social choice theory. Oxford: Oxford University Press. ISBN 0-19-929751-7. 
• John C. Harsanyi, 1987, “interpersonal utility comparisons," The New Palgrave: A Dictionary of Economics, v. 2, pp. 955–58.
• Moulin, Herve (1988). Axioms of cooperative decision making. Cambridge: Cambridge University Press. ISBN 0-521-42458-5. 
• Nitzan, Shmuel (2010). Collective Preference and Choice. Cambridge, UK: Cambridge University Press. ISBN 0-521-72213-6. 
• Lionel Robbins, 1935, 2nd ed.. An Essay on the Nature and Significance of Economic Science, ch. VI
• ____, 1938, "Interpersonal Comparisons of Utility: A Comment," Economic Journal, 43(4), 635–41
• Amartya K. Sen, 1970 [1984], Collective Choice and Social Welfare. ISBN 0-444-85127-5 Description.
• _____, 1998, "The Possibility of Social Choice," Nobel lecture.
• _____, 1987, “social choice," The New Palgrave: A Dictionary of Economics, v. 4, pp. 382–93.
• _____, 2008. “social choice,". The New Palgrave Dictionary of Economics, 2nd Edition, Abstract.
• Shoham, Yoav; Leyton-Brown, Kevin (2009). Multiagent Systems: Algorithmic, Game-Theoretic, and Logical Foundations. New York: Cambridge University Press. ISBN 978-0-521-89943-7. http://www.masfoundations.org. . A comprehensive reference from a computational perspective; see Chapter 9. Downloadable free online.
• Kotaro Suzumura, 1983, Rational Choice, Collective Decisions, and Social Welfare. ISBN 0-521-23862-5
• Taylor, Alan D. (2005). Social choice and the mathematics of manipulation. New York: Cambridge University Press. ISBN 0-521-00883-2. 

External links

• The Society for Social Choice and Welfare
  • Social Choice and Welfare
• Social Choice Bibliography by J. S. Kelly]