Multiple-Stage Decision-Making: The Effect of Planning Horizon Length on Dynamic Consistency

Many decisions involve multiple stages of choices and events, and these decisions can be represented graphically as decision trees. Optimal decision strategies for decision trees are commonly determined by a backward induction analysis that demands adherence to three fundamental consistency principles: dynamic, consequential, and strategic. Previous research (Busemeyer et al. 2000, J. Exp. Psychol. Gen. 129, 530) found that decision-makers tend to exhibit violations of dynamic and strategic consistency at rates significantly higher than choice inconsistency across various levels of potential reward. The current research extends these findings under new conditions; specifically, it explores the extent to which these principles are violated as a function of the planning horizon length of the decision tree. Results from two experiments suggest that dynamic inconsistency increases as tree length increases; these results are explained within a dynamic approach–avoidance framework. This revised version was published online in June 2006 with corrections to the Cover Date.     

Ambiguity,pessimism, and rational religious choice

Using a subclass of the α-maximin expected-utility preference model, in which the decision maker’s degree of ambiguity and degree of pessimism are each parameterized, we present a theory of religious choice in the Pascalian decision theory tradition, one that can resolve dilemmas, address the “many Gods objection,” and address the ambiguity inherent in religious choice. Parameterizing both the degree of ambiguity and the degree of pessimism allows one to examine how the two interact to impact choice, which is useful regardless of the application. Applying this model to religious choice is a move beyond subjective expected-utility theory, allowing us to show that a change in either the degree of ambiguity or the degree of pessimism can lead a decision maker to “convert” from one religion to another.     

On the possibility of rational policy evaluation

Arrow proved the inconsistency of a set of reasonable looking conditions on a social decision rule. These conditions are stated and their rationale explained. It is argued that the blame for the inconsistency must lie with Arrow's Collective Rationality condition. Arrow's abstract problem is generalized and interpreted in terms of individual as well as collective decision-making. His conditions are revised so that (1) cardinal - even interpersonal - utility comparisons are allowed and (2) the Collective Rationality condition - which formulates the traditional conception of rational choice as maximizing choice - is weakened to its bare bones. The revised set of conditions is still inconsistent. Once again the culprit is the Collective Rationality condition, now drastically weakened: even the bare bones of Arrow's conception of rational choice as maximizing choice is untenable. An alternative conception is proposed.     

Dynamic Choice and NonExpected Utility

This paper explores how some widely studied classes of nonexpected utility models could be used in dynamic choice situations. A new "sequential consistency" condition is introduced for single-stage and multi-stage decision problems. Sequential consistency requires that if a decision maker has committed to a family of models (e.g., the multiple priors family, the rank-dependent family, or the betweenness family) then he use the same family throughout. Conditions are presented under which dynamic consistency, consequentialism, and sequential consistency can be simultaneously preserved for a nonexpected utility maximizer. An important class of applications concerns cases where the exact sequence of decisions and events, and thus the dynamic structure of the decision problem, is relevant to the decision maker. It is shown that for the multiple priors model, dynamic consistency, consequentialism, and sequential consistency can all be preserved. The result removes the argument that nonexpected utility models cannot be consistently used in dynamic choice situations. Rank-dependent and betweenness models can only be used in a restrictive manner, where deviation from expected utility is allowed in at most one stage.     

The Use of Base Rate Information as a Function of Experienced Consistency

Three experiments examine the effect of base rate consistency under direct experience. Base rate consistency was manipulated by blocking trials and setting base rate choice reinforcement to be either consistent or inconsistent across trial blocks. Experiment 1 shows that, contrary to the usual finding, participants use base rate information more than individuating information when it is consistent, but less when it is inconsistent. In Experiment 2, this effect was replicated, and transferred in verbal questions posed subsequently. Despite experience with consistent base rates increasing sensitivity to base rates in word problems, verbal responses were far from normative. In Experiment 3, participants’ use of base rates was once again moderated by its consistency, but this effect was itself moderated by the diagnosticity of base rate information. Participants were highly accurate in estimating experienced base rates. These studies demonstrate that base rate usage is complex and a function of how base rates are presented (experienced versus summary statistics) and response format (choice proportions versus probability estimates). Knowledge of base rates was insufficient for proper usage in verbal word problems. Although choice proportions showed a sophisticated sensitivity to experienced base rate information, participants seemed unable to demonstrate a similar sophistication when given typical word problems indicating that base rate neglect is a function of information representation and not an inherent processing bias.     

Consumer‐directed care for older Australians: Are resources identified on the Web adequate to support decisions about home‐based care packages?

Consumer‐directed care (CDC) was introduced as part of aged care policy reforms in Australia in 2012. CDC aims to promote choice and control for people with complex needs who need home care and supports. While more choices may bring benefits, information and resources are needed by people to navigate new and complex care‐related decisions. In 2017, we identified the resources available to support consumers of the new CDC Home Care Packages (HCP) program via an Internet search. Forty‐six resources were analysed to assess the adequacy of information to inform care choices. General information was most frequently found, but information to guide specific choices, such as choosing or changing service providers, was limited. Accessibility of information was limited for non‐English speakers and for people with low literacy or reduced capacity for decision making. No training opportunities were identified, and only one non‐partisan organisation offered support for decision making. Overall, the information and supports analysed were not adequate to assist older people to make choices to ensure consumer direction of care. There is an urgent need to improve the quality and accessibility of information and provide training and support for choice, particularly for those with limited decision‐making capacity, such as those living with dementia.     

Portfolio Inertia and Epsilon-Contaminations

This article analyzes investors’ portfolio selection problems in a two-period dynamic model of Knightian uncertainty. We account for the existence of portfolio inertia in this two-period framework. Furthermore, by incorporating investors’ updating behavior, we analyze how observing new information in the first period will affect investors’ behavior. By this analysis, we show that observing new information in the first period will expand portfolio inertia in the second period compared with the case in which observing new information has not been gained in the first period if the degree of Knightian uncertainty is sufficiently large.     

Valuing Others’ Information under Imperfect Expectations

Sometimes we believe that others receive harmful information. However, Marschak’s value of information framework always assigns non-negative value under expected utility: it starts from the decision maker’s beliefs – and one can never anticipate information’s harmfulness for oneself. The impact of decision makers’ capabilities to process information and of their expectations remains hidden behind the individual and subjective perspective Marschak’s framework assumes. By introducing a second decision maker as a point of reference, this paper introduces a way for evaluating others’ information from a cross-individual, imperfect expectations perspective for agents maximising expected utility. We define the cross-value of information that can become negative – then the information is “harmful” from a cross-individual perspective – and we define (mutual) cost of limited information processing capabilities and imperfect expectations as an opportunity cost from this same point of reference. The simple relationship between these two expected utility-based concepts and Marschak’s framework is shown, and we discuss evaluating short-term reactions of stock market prices to new information as an important domain of valuing others’ information.      

A Note on the Portfolio Selection Problem

In this note we provide new results of interest in the portfolio choice problem when the risky opportunities are correlated: for a general vector (X₁, X₂,..., X_n) of risky opportunities we give new conditions for stochastic comparison among different portfolios choices and new necessary and sufficient conditions to characterize the portfolio which gives the maximal expected utility.     

Valuing future cash flows with non separable discount factors and non additive subjective measures: conditional Choquet capacities on time and on uncertainty

We consider future cash flows that are contingent both on dates in time and on uncertain states. The decision maker (DM) values the cash flows according to its decision criterion: Here, the payoffs’ expectation with respect to a capacity measure. The subjective measure grasps the DM’s behaviour in front of the future, in the spirit of de Finetti’s (1930) and of Yaari’s (1987) Dual Theory in the case of risk. Decomposition of the criterion into two criteria that represent the DM’s preferences on uncertain payoffs and time contingent payoffs are derived from Ghirardato’s (1997) results. Conditional Choquet integrals are defined by dynamic consistency (DC) requirements and conditional capacities are derived, under some conditions on information. In contrast with other models referring to DC, ours does not collapse into a linear one because it violates a weak version of consequentialism.     

Naive,resolute or sophisticated? A study of dynamic decision making

Dynamically inconsistent decision makers have to decide, implicitly or explicitly, what to do about their dynamic inconsistency. Economic theorists have identified three possible responses—to act naively (thus ignoring the dynamic inconsistency), to act resolutely (not letting their inconsistency affect their behaviour) or to act sophisticatedly (hence taking into account their inconsistency). We use data from a unique experiment (which observes both decisions and evaluations) in order to distinguish these three possibilities. We find that the majority of subjects are either naive or resolute (with slightly more being naive) but very few are sophisticated. These results have important implications for predicting the behaviour of people in dynamic situations.

Negotiation and Defeasible Decision Making

In economically meaningful interactions negotiations are particularly important because they allow agents to improve their information about the environment and even to change accordingly their own characteristics. In each step of a negotiation an agent has to emit a message. This message conveys information about her preferences and endowments. Given that the information she uses to decide which message to emit comes from beliefs generated in previous stages of the negotiation, she has to cope with the uncertainty associated with them. The assessment of the states of the world also evolves during the negotiation. In this paper we analyze the intertwined dynamics of beliefs and decision, in order to determine conditions on the agents that allow them to reach agreements. The framework for decision making we consider here is based on defeasible evaluation of possibilities: an argument for a choice defeats another one if it is based on a computation that better uses all the available information.     

The evolving risks of the 21st century and their effective management

Risk management institutions can be reinvented in the 21st century in response to the changing nature of economic uncertainties and changing information technology. The COVID-19 pandemic and its effects on the economy provide an example of new kinds of uncertainties to be managed. National and international contracts should manage risks to claims on better-defined economic aggregates and prices of factors of human capital to make for better economic measurements and better risk management opportunities. The failures of international management of the COVID-19 pandemic, including failure to control the spread of misinformation, provide lessons for such new financial arrangements     

On the significance of social control: Treatment‐entry pressures,self‐choice and alcohol and drug dependence criteria one year after treatment

Storbjörk J. On the significance of social control: treatment‐entry pressures, self‐choice and alcohol and drug dependence criteria one year after treatment This article explores how self‐choice and treatment‐entry pressures are associated with one‐year treatment outcome (dependence symptoms, 0–6, 12 months) among alcohol and drug misusers, respectively. Informal pressures (from family and friends), formal pressures (related to work, healthcare, social services, social allowances, child custody) and legal pressures (related to the police, criminal justice system, compulsory treatment) were analysed. A sample (N= 1,210) representative of the addiction treatment system of Stockholm County was interviewed when starting a new treatment episode and after one year. Regression analyses indicated that self‐choice and pressures are associated with outcome among alcohol misusers but not among drug misusers when controlling for background factors and severity. Self‐choice (without pressures) correlated with a good outcome (a lower number of dependence criteria). Pressures were generally associated with poorer outcome. Alcohol misusers who had experienced threats regarding child custody did better in comparison with those not experiencing such pressure. The difference in results by drug type and implications were discussed.     

The Independence Postulate,Hypothetical and Called-off Acts: a further reply to Rabinowicz

The Independence postulate links current preferences between called-off acts with current preferences between constant acts. Under the assumption that the chance-events used in compound von Neumann-Morgenstern lotteries are value-neutral, current preferences between these constant acts are linked to current preferences between hypothetical acts, conditioned by those chance events. Under an assumption of stability of preferences over time, current preferences between these hypothetical acts are linked to future preferences between what are then and there constant acts. Here, I show that a failure of Independence with respect to current preferences leads to an inconsistency in sequential decisions. Two called-off acts are constructed such that each is admissible in the same sequential decision and yet one is strictly preferred to the other. This responds to a question regarding admissibility posed by Rabinowicz ([2000] Preference stability and substitution of indifferents: A rejoinder to Seidenfeld, Theory and Decision 48: 311–318 [this issue]).     

Subjective Probability Weighting and the Discovered Preference Hypothesis

Numerous studies have convincingly shown that prospect theory can better describe risky choice behavior than the classical expected utility model because it makes the plausible assumption that risk aversion is driven not only by the degree of sensitivity toward outcomes, but also by the degree of sensitivity toward probabilities. This article presents the results of an experiment aimed at testing whether agents become more sensitive toward probabilities over time when they repeatedly face similar decisions, receive feedback on the consequences of their decisions, and are given ample incentives to reflect on their decisions, as predicted by Plott’s Discovered Preference Hypothesis (DPH). The results of a laboratory experiment with N = 62 participants support this hypothesis. The elicited subjective probability weighting function converges significantly toward linearity when respondents are asked to make repeated choices and are given direct feedback after each choice. Such convergence to linearity is absent in an experimental treatment where respondents are asked to make repeated choices but do not experience the resolution of risk directly after each choice, as predicted by the DPH. I thank Peter P. Wakker for useful comments and suggestions.