Rationality and Order-Dependent Sequential Rationality

We show that an individual using a choice function is sequentially rational and the decisions he makes are independent of the order of implementation of the rationales if and only if he is rational with the union of the rationales as a base binary relation. When he makes his decisions following a choice correspondence, the sufficiency part of this claim still holds, the necessity part of it does not.      

Sequential Parimutuel Betting in the Laboratory

This paper investigates parimutuel betting in the laboratory. Our experimental design relies on a simple sequential betting game where equilibrium strategies are characterized according to objective probabilities, the number of bettors, and publicly observable odds. The empirically well-documented phenomenon referred to as the favorite-longshot bias is observed in two of our three treatments. We offer a theoretical explanation of the subjects' behavior which relies on rank-dependent expected utility and pessimistic expectations about future bets.     

Reference Wealth Effects in Sequential Choice

It is argued that in order to accommodate experimentally-observed choice patterns, it is not enough to model the utility function as being dependent on changes from a reference wealth point. Instead, individuals should be modeled as treating decisions as part of an identifiable sequence of decisions, and utility should be a function of reference wealth, income so far from the sequence, and payoffs from the current decision. The three-argument utility function allows for risk aversion over gains and risk seeking over losses for the first choice in the sequence, and for the house money and break-even effects in later decisions.     

Sequential asymmetric auctions with endogenous participation

In this paper we suggest a model of sequential auctions with endogenous participation where each bidder conjectures about the number of participants at each round. Then, after learning his value, each bidder decides whether or not to participate in the auction. In the calculation of his expected value, each bidder uses his conjectures about the number of participants for each possible subgroup. In equilibrium, the conjectured probability is compatible with the probability of staying in the auction. In our model, players face participation costs, bidders may buy as many objects as they wish and they are allowed to drop out at any round. Bidders can drop out at any time, but they cannot come back to the auction. In particular we can determine the number of participants and expected prices in equilibrium. We show that for any bidding strategy, there exists such a probability of staying in the auction. For the case of stochastically independent objects, we show that in equilibrium every bidder who decides to continue submits a bid that is equal to his value at each round. When objects are stochastically identical, we are able to show that expected prices are decreasing.     

Sequential strategies in dual control problems

Sequential decision problems are studied in which there are two decision-makers, or players, who are trying to control the same stochastic system in order to minimize their own individual expected losses. The standard linear model for the stochastic control process and standard quadratic loss functions are assumed. The players take turns choosing the value of the control variable, and each player has his own sequence of targets and his own loss function. Optimal pure competitive strategies are derived by backward induction, and limiting strategies and equilibria are determined. Myopic strategies are introduced and shown to yield smaller losses for each player than the pure competitive strategies. Coefficients of cooperation are then defined, and various cooperative sequential strategies based on them are shown to be mutually beneficial to both players.     

The Aversion to the Sequential Resolution of Uncertainty

This paper sets forth and offers an explanation for preferences for the form of the timing of resolution of uncertainty; namely for uncertainty to be resolved all at one time rather than sequentially. The explanation is based on a weakening of the independence axiom, in particular on the notion of disappointment aversion developed in Gul's (1991) axiomatic model of preferences. Implications of this aversion are discussed for issues in finance, intertemporal decision making under uncertainty, high stakes risky situations and consumer self-regulation. The analysis encourages a formulation of preferences over all attributes of interest to the decision maker, including psychological satisfaction.     

Sophisticated Voting Under the Sequential Voting by Veto1

The research reported here was the first empirical examination of strategic voting under the Sequential Voting by Veto (SVV) voting procedure, proposed by Mueller (1978). According to this procedure, a sequence of n voters must select s out of s+m alternatives (mn2; s>0). Hence, the number of alternatives exceeds the number of participants by one (n+1). When the ith voter casts her vote, she vetoes the alternative against which a veto has not yet been cast, and the s remaining non-vetoed alternatives are elected. The SVV procedure invokes the minority principle, and it has advantages over all majoritarian procedures; this makes SVV a very desirable means for relatively small groups to make collective decisions. Felsenthal and Machover (1992) pointed out three models of voting under SVV: sincere, optimal, and canonical. The current research investigated, through laboratory experiments, which cognitive model better accounts for the voters' observed behavior and the likelihood of obtaining the optimal outcome as a function of the size of n (when s=1). The findings suggest that while voters under SVV use all three models, their choice is conditioned by group size. In the small groups (n=3), the canonical mode was a better predictor than the sincere model. In the larger groups (n=5), the sincere model was a better predictor than the canonical model. There is also evidence of players' learning during the experiment.     

Sequential decision making without independence: a new conceptual approach

This paper presents a critical reflection on dynamic consistency as commonly used in economics and decision theory, and on the difficulty to test it experimentally. It distinguishes between the uses of the term dynamic consistency in order to characterize two different properties: the first accounts for the neutrality of individual preferences towards the timing of resolution of uncertainty whereas the second guarantees that a strategy chosen at the beginning of a sequential decision problem is immune to any reevaluation and will effectively be implemented from then on in the decision problem. Although these two properties are equivalent under expected utility (EU), this is not the case under non-EU. Building on the possible characteristics of individual dynamic preferences under risk, this paper proposes a conceptual categorization, that is experimentally testable, of possible sequential decision making behaviors of non-EU maximizers.     

Sequential voting by veto: Making the Mueller-Moulin algorithm more versatile

This paper shows that a relatively easy algorithm for computing the (unique) outcome of a sophisticated voting procedure called sequential voting by veto (SVV) applies to a more general situation than considered hitherto. According to this procedure a sequence of n voters must select s out of m + s options (s > 0, m 3 n 3 2). The ith voter, when his turn comes, vetoes k _i options (k _i 1, k _i = m). The s remaining non-vetoed options are selected. Every voter is assumed to be fully informed of all other voters total (linear) preference orderings among the competing options, as well as of the order in which the veto votes are cast. This algorithm was proposed by Mueller (1978) for the special case where s and the k _i are all equal to 1, and extended by Moulin (1983) to the somewhat more general case where the k _i are arbitrary but s is still 1. Some theoretical and practical issues of voting by veto are discussed.     

The Favorite-Longshot Bias in Sequential Parimutuel Betting with Non-Expected Utility Players

This paper analyzes a model of sequential parimutuel betting described as a two-horse race with a finite number of noise bettors and a finite number of strategic and symmetrically informed bettors. For generic objective probabilities that the favorite wins the race, a unique subgame perfect equilibrium is characterized. Additionally, two explanations for the favorite–longshot bias—according to which favorites win more often than the market's estimate of their winning chances imply—are offered. It is shown that this robust anomalous empirical regularity might be due to the presence of transaction costs and/or to strategic bettors' subjective attitude to probabilities.