Maxmin Expected Utility was first axiomatized by Gilboa and Schmeidler in an Anscombe–Aumann setup Anscombe and Aumann which includes exogenous probabilities. The model was later axiomatized in a purely subjective setup, where no exogenous probabilities are assumed. The purpose of this note is to show that in all these axiomatizations, the only assumptions that are needed are the basic ones that are used to extract a cardinal utility function, together with the two typical Maxmin assumptions, Uncertainty Aversion and Certainty Independence, (...) applied only to 0.5:0.5 mixtures. For the purely subjective characterizations, this means that assumptions involving an unbounded number of variables can be replaced with assumptions that involve only a finite number thereof. (shrink)

This paper provides a general framework for analyzing self-confirming policies. We study self-confirming equilibria in recurrent decision problems with incomplete information about the true stochastic model. We characterize stationary monetary policies in a linear-quadratic setting.

Source preference in which equally distributed risks may be valued differently has been receiving increasing attention. Using subjects recruited in Berkeley, Fox and Tversky demonstrate a familiarity bias in source preference—betting on a less than even-chance event based on San Francisco temperature is valued more than betting on a better than even-chance event based on Istanbul temperature. Neophobia is associated with the amygdala which is GABA-rich and is known to be modulated by benzodiazepines as anxiolytic agents that enhance the activity (...) of the GABAA receptor in processing anxiety and fear. This leads to our hypothesis that familiarity bias in decision making may be explained by polymorphic variations in this receptor mediated by anxiety regulation in the amygdala. In two companion studies involving Beijing-based subjects, we examine 10 single nucleotide polymorphisms of GABRB2 and find 7 SNPs each showing negative association between familiarity bias—preference for betting on parity of Beijing temperature over Tokyo temperature—and having at least one minor allele. In an imaging genetics study of a subsample of subjects based on the SNP with the most balanced allelic distribution, we find that subjects’ familiarity bias in terms of risk aversion towards bets on the parity of the temperature of 20 Chinese cities is negatively associated with their post-scanning familiarity ratings of the cities only for those with no minor allele in this SNP. Moreover, familiarity bias is positively associated with activation in the right amygdala along with the brain’s attention networks. Overall, our findings help discriminate between ambiguity aversion and familiarity bias in source preference and supports our gene–brain–behavior hypothesis of GABAergic modulation of amygdala activation in response to familiarity towards the source of uncertainty. (shrink)

The main purpose of this paper is to show that left-monotone risk aversion, a meaningful refinement of strong risk aversion, characterizes decision makers for whom deductible insurance is optimal. A second goal is to prove that the deductible’s computation is particularly tractable in the case of Yaari’s decision makers.

The growing literature on how people learn to make decisions based on experience focuses on two types of paradigms. In one paradigm, people are faced with a choice, and must retrospectively consult past experience of similar choices to decide what to do. In the other paradigm, people are faced with a choice, and then have the opportunity prospectively to gather new experiences that might help them make that choice. The current paper examines the joint impact of both retrospective and prospective (...) experiences. Two experiments reveal strong interactions. In Study 1, repeated experience with new samples appears to reduce sensitivity to the average outcome in the samples and enhances underweighting of rare events. Study 2 shows that repeated experience with pre-choice samples can reverse the impact of the new information. The results suggest that prospectively gathering new samples can have two, potentially contrasting, influences on choice: the first focuses on the sample’s face value and selects the option with the higher value in the new sample; by contrast, the second treats the new sample as a cue to recall similar prior experiences, which in turn drive choice. The paper concludes with a discussion of the possibility that part of the descriptive value of prospect theory reflects the fact that it summarizes the joint impact of similar “face-or-cue” processes. (shrink)

Original and cumulative prospect theory differ in the composition rule used to combine the probability weighting function and the value function. We test the predictive power of these composition rules by performing a novel out-of-sample prediction test. We apply estimates of prospect theory’s weighting and value function obtained from two-outcome cash equivalents, a domain where original and cumulative prospect theory coincide, to three-outcome cash equivalents, a domain where the composition rules of the two theories differ. Although both forms of prospect (...) theory predict three-outcome cash equivalents very well, at the aggregate level, we find small but systematic under-prediction of cash equivalents for cumulative prospect theory and small but systematic over-prediction of cash equivalents for original prospect theory. We also observe substantial heterogeneity across subjects and types of gambles, some of which is accounted for by differences in the curvature and elevation of the weighting function across individuals. We also find differences in prediction related to whether the worst outcome is zero or non-zero. (shrink)

We establish a simple condition, based on the willingness to bet on events, under which two biseparable preferences have cardinally equivalent utilities.

Interest in the foundations of the theory of choice under uncertainty was stimulated by applications of expected utility theory such as the Sandmo model of production under uncertainty. The development of generalized expected utility models raised the question of whether such models could be used in the analysis of applied problems such as those involving production under uncertainty. Finally, the revival of the state-contingent approach led to the recognition of a fundamental duality between choice problems and production problems.

With concerns regarding climate change rising, companies and policy makers seek to understand the precursors to environmentally-friendly consumer choice. Decision modes are the qualitatively different psychological processes employed to arrive at decisions. Across six studies, the present project establishes which decision modes are employed by consumers to decide between electricity plans that differ in environmental impact, and how employed decision modes affect those choices. We demonstrate that consumers are most likely to use Calculation Modes when facing such choices. Importantly, we (...) find that Affect or Role Modes promote more environmentally-friendly choices, while Calculation Modes decrease environmentally-friendly choices. Experimentally promoting use of a Role Mode over a Calculation Mode increases selection of environmentally-friendly alternatives, and the relative degree of employing the Role Mode mediates this effect. Our findings provide insight into how decision mode usage can alter environmental decisions, and suggest mechanisms and tools for marketers and policy makers to influence consumer choice. (shrink)

I reconsider Bleichrodt, Pinto Prades and Wakker’s 2001 paper about eliciting utility measures from stated preference surveys. That paper pioneers a method that is now widely used in behavioural economics to correct individuals’ ‘biases’ and to recover their ‘true preferences’. However, BPW propose this method as way of dealing with inconsistent responses to stated preference surveys, in contrast to more recent applications which aim to help individuals to avoid supposed mistakes in their private choices. I argue that the concepts of (...) true preference and bias are empirically ungrounded, but that BPW’s approach can be interpreted as not invoking those concepts. By ‘regularising’ preferences revealed in actual choice, this approach constructs measures of individual welfare that are broadly aligned with actual preferences and consistent with normative standards of rationality that are appropriate for public decision-making. Public decision-makers’ normative judgements are made explicit, rather than being disguised as apparently empirical claims about true preferences. (shrink)

We analyse the incentives of individuals to misrepresent their truthful judgments when engaged in collective decision-making. Our focus is on scenarios in which individuals reason about the incentives of others before choosing which judgments to report themselves. To this end, we introduce a formal model of strategic behaviour in logic-based judgment aggregation that accounts for such higher-level reasoning as well as the fact that individuals may only have partial information about the truthful judgments and preferences of their peers. We find (...) that every aggregation rule must belong to exactly one of three possible categories: it is either immune to strategic manipulation for every level of reasoning, or manipulable for every level of reasoning, or immune to manipulation only for every kth level of reasoning, for some natural number k greater than 1. (shrink)

The existence of a strong link between socio-economic background and individual preferences has been documented among both children and grown-ups. Here, we study whether such a correlation persists even in a highly homogeneous population of young adults: university students. Our findings indicate that participants living in an area characterized by a high socio-economic environment tend to trust more and are more inclined to reciprocate higher levels of trust, as compared to those coming from less wealthy neighborhoods. This behavioral difference is, (...) at least in part, driven by heterogeneities in beliefs: subjects from the most affluent part of the city have more optimistic expectations on their counterpart’s trustworthiness than those living in a lower socio-economic environment. By contrast, no significant differences emerge in other preferences: generosity, risk attitudes, and time preferences. Finally, we do not find any systematic evidence of out-group discrimination based on neighborhood identity. (shrink)

We study the effect of scarcity on decision making by low income Swedes. We exploit the random assignment of welfare payments to study their borrowing decisions within the pawn and mainstream credit market. We document that higher educated borrowers borrow less frequently and choose lower loan to value ratios when their budget constraints are exogenously tighter. In contrast, low-educated borrowers do not respond to temporary elevated levels of scarcity. This lack of response translates into a significantly higher probability to default (...) and an 11.6% increase in borrowing cost. We show that a difference in access to liquidity and/or buffer stocks cannot explain our results. Instead a framework, where the awareness of self-control problems is positively correlated with education can explain that high-educated consumers choose a lower LTV as a commitment device to increase their likelihood to repay. Analogously, low-educated with less awareness of their future self-control problems, do not tie themselves to the mast and thus ignore the consequences of their credit decisions when focusing on solving acute liquidity problems. Our findings highlight that increased levels of scarcity risk reinforcing the conditions of poverty through overborrowing. (shrink)

Poverty is associated with a wide range of counterproductive economic behaviors. Scarcity theory proposes that poverty itself induces a scarcity mindset, which subsequently forces the poor into suboptimal decisions and behaviors. The purpose of our work is to provide an integrated, up-to-date, critical review of this theory. To this end, we reviewed the empirical evidence for three fundamental propositions: Poverty leads to attentional focus and neglect causing overborrowing, poverty induces trade-off thinking resulting in more consistent consumption decisions, and poverty reduces (...) mental bandwidth and subsequently increases time discounting and risk aversion. Our findings indicate that the current literature predominantly confirms the first and second proposition, although methodological issues prevent a firm conclusion. Evidence for the third proposition was not conclusive. Additionally, we evaluated the overall status of scarcity theory. Although the theory provides an original, coherent, and parsimonious explanation for the relationship between financial scarcity and economic decision making, the theory does not fully accord with the data and lacks some precision. We conclude that both theoretical and empirical work are needed to build a stronger theory. (shrink)

Scarcity sharpens the conflict between short term gains and long term sustainability. Psychological research documents that decision makers focus on immediate needs under scarcity and use available resources more effectively. However, decision makers also borrow too much from future resources and overall performance decreases as a consequence. Using an online experiment, we study how scarcity affects borrowing decisions in groups. We first document that scarcity affects groups in a similar way as individuals. Then, we go on to show that the (...) negative effect of scarcity is weaker for groups than for individuals. Even in a minimal design that excludes direct interaction or communication, the fact that participants know that their own behavior affects and can be partly observed by another participant disciplines their use of scarce resources. Our results thus highlight the benefit of groups as units of human organization. (shrink)

The risky investment game of Gneezy and Potters :631–645, 1997) has been proposed as a simple tool to measure risk aversion in applied settings, especially attractive in settings where participants may have limited education. However, this game can produce a significant endowment effect, so that analysis of the behavior in this game should not be done in the Expected Utility Theory framework. The paper illustrates this point, by showing that risk tolerance can be much higher when the initial endowment concerns (...) a risky lottery. (shrink)

Probability weighting is a marked feature of decision-making under risk. For poor people in rural areas of developing countries, how probabilities are evaluated matters for livelihoods decisions, especially the probabilities associated with losses. Previous studies of risky choice among poor people in developing countries seldom consider losses and do not offer a refined tracking of the probability-weighting function. We investigate probability weighting among smallholder farmers in Uganda, separately for losses and for gains, using a method that allows refined tracking of (...) the PWF for a population with low levels of literacy. For losses, we find marked probability weighting near zero, which is in line with evidence found in Western labs. For gains, the absence of probability weighting is remarkable, particularly its absence near 100%. We also find marked differences in probability weighting for traditional farmers which are in line with the observed livelihoods strategies in the study area. (shrink)