behavioral decision theory Gad Saad Theories of decision making are either normative, prescriptive, or descriptive (Bell, Raiffa, and Tversky, 1988; Fischhoff, 2010). Axioms of rational choice as espoused by many classical economists constitute the standard normative model of human decision making. Transitivity of preferences is an example of such an axiom of rationality. If a consumer prefers product A to product B, and product B to product C, then from a rational/normative perspective it must be the case that product A is preferred to product C. Prescriptive theories of decision making offer frameworks for reaching optimal decisions wherein optimality is defined using clearly specified mathematical metrics. For example, the traveling salesman problem in operations research has been studied extensively for several decades. The objective is to identify the shortest route to take while ensuring to visit each of n number of cities only once each. In this sense, proposed solutions are prescriptive in that they offer a tangible means by which to solve this optimization problem. The third class of theories of decision making are descriptive in that they offer accounts of how individuals actually make decisions rather than how they ought to, which is the case with prescriptive and normative models. Much of the work in behavioral decision theory (BDT) falls within this third category (see Kahneman, 2011 for a broad overview of this research stream). More specifically, the great majority of works within BDT has sought to identify ways by which humans violate axioms of rational choice (e.g., transitivity, independence of irrelevant alternatives, procedural invariance). Another research stream within BDT has sought to uncover a wide range of decision rules (or heuristics) utilized by decision makers when making multiattribute choices. This paradigm typically uses informational display boards (IDB) as its methodological tool of choice. An IDB is an n×m matrix where the n rows correspond to the n alternatives to choose from, and the m columns are the attributes on which the alternatives are rated. The weighted additive rule (WADD) is the normative rule in such an instance∑where the WADD score of alternative A = (Wi × Ai ), for i = 1 to m. This process is repeated for all n alternatives and the one with the highest total WADD score is chosen. The reality though is that individuals seldom utilize all of the available information (as implied by WADD) prior to choosing an alternative. Examples of heuristics that have been uncovered include the Lexicographic rule (choose the alternative that scores the best on the most important attribute), the Disjunctive rule (choose the first alternative that passes any of the attribute cutoffs as set by the decision maker), the Equal Weights rule (same as WADD but ignore the attribute weights), the Majority of Confirming Dimensions rule (choose the alternative that is superior on the most number of attributes), and the Satisficing rule (choose the first alternative that meets or exceeds all of the attribute cutoffs as set by the decision maker). Other heuristics include the Conjunctive, Lexicographic Semiorder, Elimination-by-Aspects, Attribute Difference, and the Frequency of Good and Bad Features heuristics (see Payne, Bettman, and Johnson, 1993 for an exhaustive discussion of all of these heuristics along with the relevant references for each of the rules). Given the plethora of possible decision rules that could be applied for any given decision, how do people choose among these (meta-decision)? In other words, when do decision makers use the Lexicographic rule versus say the WADD rule? The accuracy-effort framework has been the operative framework in tackling this issue. Each decision rule carries a differential level of cognitive effort along with its unique relative accuracy (e.g., WADD is more effortful than Disjunctive, but it is also more accurate as it processes more of the available information). In their seminal book The Adaptive Decision Maker, Payne, Bettman, and Johnson (1993) provided an extensive treatise of how individuals navigate through the effort-accuracy trade-off as a function of a wide range of factors including task effects (e.g., the size of the IDB) and context effects (e.g., how correlated the attribute values are for a given decision). For example, when facing time pressure, it is best from an accuracy perspective to sample a little bit of attribute information on all alternatives than to acquire Wiley Encyclopedia of Management, edited by Professor Sir Cary L Cooper. Copyright © 2014 John Wiley & Sons, Ltd. 2 behavioral decision theory all of the attribute information for only one alternative. That individuals do not utilize a rigid and invariant decision process in making choices (as assumed by classical economists) and instead adapt their behaviors to the tasks and contexts at hand is a central tenet of bounded rationality as originally espoused by the late Nobel Laureate Herbert A. Simon. Notwithstanding this important conceptual advance, BDT researchers have spent too much of their intellectual efforts demonstrating the ways in which our bounded minds violate normative rationality. It is now abundantly clear that Homo economicus is not an accurate representation of Homo sapiens. To avoid becoming a stagnant discipline, BDT must move beyond an obsessive cataloging of violations of rational choice and instead explore the evolutionary roots of our decision making proclivities (see Wilke and Todd, 2012 for an exhaustive review of the nexus between evolution and decision making). Congruent with this objective, several scholars have offered new definitions of rationality rooted in the recognition of the evolutionary forces that have shaped human minds, including ecological rationality (Gigerenzer, Todd, and the ABC Research Group, 1999; Todd, Gigerenzer, and the ABC Research Group, 2012), deep rationality (Kenrick et al., 2009), and adaptive rationality (Haselton and Nettle, 2006; Haselton et al., 2009). Stopping strategies constitute another fertile area of research within the BDT literature. A central element of any decision whether choosing a mate, accepting a job offer, hiring an employee, or purchasing a car, is determining when to terminate the information search process. Behavioral decision theorists have uncovered several such stopping strategies using the sequential choice paradigm. Sequential choice refers to the fact that at each step of a decision, individuals can either stop and choose one of the alternatives, or continue to acquire additional information. In some instances, sequential choice is attribute-based, namely the number of alternatives is fixed (typically at two) but the amount of attribute information that can be acquired on the competing alternatives can vary (Saad and Russo, 1996). For example, within the American political landscape, the last step in a presidential election is deciding between the two final remaining candidates. In other cases, the sequential choice process is alternative-based, as per the classic secretary problem (see Ferguson, 1989 for a review). Suppose that one has to hire a new secretary out of a sample of n possible candidates, and that it is crucially important that the one that is hired is the best of the n candidates. If n is large, it is likely implausible to interview all of the available candidates. Rather, some optimal stopping strategy must be used that maximizes the likelihood that the best candidate is chosen without having to sample all n options. Candidates are interviewed one at a time, and at each step one must decide whether to stop and choose the current interviewee or proceed by interviewing another candidate, without having the ability to go back and choose a previously rejected candidate. In this class of sequential choices, the iterative counter is over the number of alternatives to evaluate prior to making a final choice. Irrespective of whether the sequential choice is attribute-based, alternative-based, or a combination of both (Saad, Eba, and Sejean, 2009, study 2), all such models recognize that contrary to normative rationality, individuals do not acquire all of the obtainable and pertinent information prior to selecting the winning alternative. Whether identifying violations of rational choice, or documenting the wide array of decision rules and stopping strategies used when individuals are facing multiattribute choices, the explanatory powers of BDT have been substantial. It is not surprising then that innumerable fields have incorporated BDT principles within their theoretical purviews including marketing, accounting, finance, risk analysis, medicine, psychology, law, negotiations, and political science. Bibliography Bell, D.E., Raiffa, H. and Tversky, A. (1988) Descriptive, normative, and prescriptive interactions in decision making, in Decision Making: Descriptive, Normative, and Prescriptive Interactions (eds D.E. Bell, H. Raiffa and A. Tversky), Cambridge University Press, New York, pp. 9–30. behavioral decision theory Ferguson, T.S. (1989) Who solved the secretary problem? Statistical Science, 4, 282–296. Fischhoff, B. (2010) Judgment and decision making. Wiley Interdisciplinary Reviews: Cognitive Science, 1, 724–735. Haselton, M.G. and Nettle, D. (2006) The paranoid optimist: an integrative evolutionary model of cognitive biases. Personality and Social Psychology Review, 10, 47–66. Haselton, M.G., Bryant, G.A., Wilke, A. et al. (2009) Adaptive rationality: an evolutionary perspective on cognitive bias. Social Cognition, 27, 732–762. Kahneman, D. (2011) Thinking, Fast and Slow, Farrar, Straus and Giroux, New York. Kenrick, D.T., Griskevicius, V., Sundie, J.M. et al. (2009) Deep rationality: the evolutionary economics of decision making. Social Cognition, 27, 764–785. Gigerenzer, G., Todd, P.M. and the ABC Research Group (1999) Simple Heuristics that Make us Smart, Oxford University Press, New York. 3 Payne, J.W., Bettman, J.R. and Johnson, E.J. (1993) The Adaptive Decision Maker, Cambridge University Press, New York. Saad, G., Eba, A. and Sejean, R. (2009) Sex differences when searching for a mate: a process-tracing approach. Journal of Behavioral Decision Making, 22, 171–190. Saad, G. and Russo, J.E. (1996) Stopping criteria in sequential choice. Organizational Behavior and Human Decision Processes, 67, 258–270. Todd, P.M., Gigerenzer, G. and the ABC Research Group (2012) Ecological Rationality: Intelligence in the World, Oxford University Press, New York. Wilke, A. and Todd, P.M. (2012) The evolved foundations of decision making, in Judgment and Decision Making as a Skill: Learning, Development, and Evolution (eds M.K. Dhami, A. Schlottmann and M. Waldmann), Cambridge University Press, New York, pp. 3–28.