Investigating Risky Choices Over Losses Using Experimental Data

We conduct a battery of experiments in which agents make choices from several pairs of all-loss-lotteries. Using these choices, we estimate a representation of individual preferences over lotteries. We find statistically and economically significant departures from expected utility maximization for many subjects. We also estimate a preference representation based on summary statistics for behavior in the population of subjects, and again find departures from expected utility maximization. Our results suggest that public policies based on an expected utility approach could significantly underestimate preferences and willingness to pay for risk reduction.JEL Classification: C91, D81     

Does exposure to unawareness affect risk preferences? A preliminary result

One fundamental assumption often made in the literature on unawareness is that risk preferences are invariant to changes of awareness. We study how exposure to unawareness affects choices under risk. Participants in our experiment choose repeatedly between varying sure outcomes and a lottery in three phases. All treatments are exactly identical in phase 1 and phase 3, but differ in phase 2. There are five different treatments pertaining to the lottery faced in phase 2: The control treatment (i.e., a standard lottery), the treatment with awareness of unawareness of lottery outcomes but known number of outcomes, the treatment with awareness of unawareness of outcomes but with unknown number of outcomes, the treatment with unawareness of unawareness of some outcomes, and the treatment with an ambiguous lottery. We study both whether behavior differs in phase 3 across treatments (between subjects effect) and whether differences of subjects’ behavior between phases 1 and phase 3 differ across treatments (within subject effects). We observe no significant treatment effects.     

Updating beliefs with imperfect signals: Experimental evidence

We conduct an experiment on individual choice under risk in which we study belief updating when an agent receives a signal that restricts the number of possible states of the world. Subjects observe a sample drawn from an urn and form initial beliefs about the urn??s composition. We then elicit how beliefs are modified after subjects receive a signal that restricts the set of the possible urns from which the observed sample could have been drawn. We find that this type of signal increases the frequency of correct assessments and that prediction accuracy is higher for lower levels of risk. We also show that prediction accuracy is higher after invalidating signals (i.e. signals that contradict the initial belief). This pattern is explained by the lower level of risk associated with invalidating signals. Finally, we find evidence for a lack of persistence of choices under high risk.     

Individual vs. group decision-making: an experiment on dynamic choice under risk and ambiguity

This paper focuses on the comparison of individual and group decision-making, in a stochastic inter-temporal problem in two decision environments, namely risk and ambiguity. Using a consumption/saving laboratory experiment, we investigate behaviour in four treatments: (1) individual choice under risk; (2) group choice under risk; (3) individual choice under ambiguity and (4) group choice under ambiguity. Comparing decisions within and between decision environments, we find an anti-symmetric pattern. While individuals are choosing on average closer to the theoretical optimal predictions, compared to groups in the risk treatments, groups tend to deviate less under ambiguity. Within decision environments, individuals deviate more when they choose under ambiguity, while groups are better planners under ambiguity rather than under risk. Our results extend the often observed pattern of individuals (groups) behaving more optimally under risk (ambiguity), to its dynamic dimension.

     

Stochastic Choice and Consistency in Decision Making Under Risk: An Experimental Study

This paper reports the results of an experiment designed to uncover the stochastic structure of individual preferences over lotteries. Unlike previous experiments, which have presented subjects with pair-wise choices between lotteries, our design allowed subjects to choose between two lotteries or (virtually) any convex combination of the two lotteries. We interpret the mixtures of lotteries chosen by subjects as a measure of the stochastic structure of choice. We test between two alternative interpretations of stochastic choice: the random utility interpretation and the deterministic preferences interpretation. The main findings of the experiment are that the typical subject prefers mixtures of lotteries rather than the extremes of a linear lottery choice set. The distribution of choices does not change between a first and second asking of the same question. We argue that this provides support for the deterministic preferences interpretation over the random utility interpretation of stochastic choice. As a subsidiary result, we find a small proportion of subjects make choices that violate transitivity, but the level of intransitive choice falls significantly over time.     

A choice for ‘me’ or for ‘us’? Using we-reasoning to predict cooperation and coordination in games

Cooperation is the foundation of human social life, but it sometimes requires individuals to choose against their individual self-interest. How then is cooperation sustained? How do we decide when instead to follow our own goals? I develop a model that builds on Bacharach (in: Gold, Sugden (eds) Beyond individual choice: teams and frames in game theory, 2006) ??circumspect we-reasoning?? to address these questions. The model produces a threshold cost/benefit ratio to describe when we-reasoning players should choose cooperatively. After assumptions regarding player types and beliefs, we predict how the extent of cooperation varies across games. Results from two experiments offer strong support to the models and predictions herein.     

Sleepiness,choice consistency,and risk preferences

We investigate the consistency and stability of individual risk preferences by manipulating cognitive resources. Participants are randomly assigned to an experiment session at a preferred time of day relative to their diurnal preference (circadian matched) or at a non-preferred time (circadian mismatched) and choose allocations between two risky assets [using the Choi et al. (Am Econ Rev 27(5):1921–1938, 2007), design]. We find that choices of circadian matched and mismatched subject are statistically similar in terms of satisfying basic requirements for preference consistency. However, mismatched subjects tend to choose riskier asset bundles.     

Learning-by-doing in an ambiguous environment

How well do revealed ambiguity preferences predict how people choose to seek new information about uncertain events? In an economics experiment, we apply a new instrument to measure ambiguity preferences, and in a later session observe to what extent the measure predicts the choice to receive costly information in a learning-by-doing game. Ambiguity averse subjects are more willing to pay to receive information, while risk averse subjects are not. Holding ambiguity preferences constant, risk averse subjects tend to perform worse than risk loving subjects. The returns to experimentation, especially for ambiguity averse subjects, suggest a not-well studied but important role that ambiguity preferences play in decision-making under uncertainty.     

The stochastic component in choice and regression to the mean

In this article, we illustrate experimentally an important consequence of the stochastic component in choice behaviour which has not been acknowledged so far. Namely, its potential to produce ‘regression to the mean’ (RTM) effects. We employ a novel approach to individual choice under risk, based on repeated multiple-lottery choices (i.e. choices among many lotteries), to show how the high degree of stochastic variability present in individual decisions can distort crucially certain results through RTM effects. We demonstrate the point in the context of a social comparison experiment.     

Risk taking on behalf of others: The role of social distance

Individuals take decisions on behalf of others in many different contexts. In this paper, we focus on lotteries with negative expected value and study if (and how) risky choices made on behalf of another person differ i) compared to decisions which do not affect anyone else, and ii) depending on the social distance between who makes the decision and who is affected by it. Our results show that social distance (i.e., whether the person affected by one’s decision is an unknown stranger or a friend) is an important determinant when people decide on behalf of others. Moreover, when deciding on behalf of a friend rather than only for themselves or a stranger, average individual behavior is closer to expected value maximization, exhibiting less risk taking. These findings suggest that responsibility for others’ outcome and the empathy gap affect the decision making process, particularly when the social distance is shortened. The results are robust to different feedback frequencies. Controlling for order effects shows that experiencing a decrease in social distance is crucial in activating this mechanism.     

The Ecology of Risk Taking

We analyze the risk level chosen by agents who have private information regarding their quality. We show that even risk-neutral agents will choose risk strategically to enhance their reputation in the market, and that such choices will be influenced by the mix of other agents' types. Assuming that the market has no strong prior about whether the agents are good or bad, good agents will choose low levels of risk, and bad agents high levels. Empirical evidence is gathered on 2462 firms over 24 years. The results support the model: agents of higher quality have less variable performance.     

Framing effects in the evaluation of multiple risk reduction

We studied how evaluation of changes in low-probability risks are affected by reference points and framing effects. Subjects considered hypothetical situations with one or two low-probability risks. Different frames were used to describe changes in risk levels. In the first experiment, subjects chose between risk-reduction options that achieved the same overall risk reduction: large reduction of one risk vs. equal (smaller) reduction of two risks. When the risks were described as losses relative to the no-risk ideal, more subjects were indifferent between the options than when the same options were described as gains relative to the status quo. In the latter case subjects preferred equal reduction of both risks, unless one risk could be reduced to zero. In a related experiment, subjects were less willing to pay any price for a commodity that carried small increases in two risks than for a commodity carrying a comparable large increase in one risk. In other experiments, subjects evaluated single changes in risks rather than comparing or evaluating pairs of changes. Subjects again placed particularly high value on reducing any risks to zero, and they were even more inclined to do so when some other risk would also be reduced to zero. In a final experiment, elimination of risk was found to be less highly valued if its source was not fully eliminated, and a status-quo effect was found. The findings are interpreted in terms of reference theories of choice.     

The Medium Prizes Paradox: Evidence From a Simulated Casino

Mainstream explanations to gambling specify conditions under which human agents are locally risk loving. Such theories, however, fail to explain the typically observed prize distribution of a few large prizes and a large number of medium ones—hence the medium prizes paradox. In the current study we show that adaptive learning models recently proposed in the literature offer a solution. Simulations of such models predict that multiple medium prizes will slow down the decrease (over time) in agents' inclination to gamble. We run a laboratory experiment that supports this explanation and shows that the positive effect of medium prizes on the inclination to gamble increases with time.     

The “bomb” risk elicitation task

This paper presents the Bomb Risk Elicitation Task (BRET), an intuitive procedure aimed at measuring risk attitudes. Subjects decide how many boxes to collect out of 100, one of which contains a bomb. Earnings increase linearly with the number of boxes accumulated but are zero if the bomb is also collected. The BRET requires minimal numeracy skills, avoids truncation of the data, allows the precise estimation of both risk aversion and risk seeking, and is not affected by the degree of loss aversion or by violations of the Reduction Axiom. We validate the BRET, test its robustness in a large-scale experiment, and compare it to three popular risk elicitation tasks. Choices react significantly only to increased stakes, and are sensible to wealth effects. Our experiment rationalizes the gender gap that often characterizes choices under uncertainty by means of a higher loss rather than risk aversion.     

Public Choices Between Life Saving Programs: The Tradeoff Between Qualitative Factors and Lives Saved

In a telephone survey 1000 adults were confronted with pairs of life saving programs that differed in number of lives saved and asked which program in each pair they would choose to implement. Respondents were also asked to rate qualitative program characteristics on 10 point scales. For most respondents, lives saved are significant in explaining program choices, as are psychological risk characteristics. The rate of technical substitution between these characteristics and lives saved is, however, inelastic. It is noteworthy that for about 20 percent of respondents, choices among programs appear to be insensitive to lives saved.     

Dynamics in risk taking with a low-probability hazard

The experiment reported in this paper identifies the effects of experience on revealed attitudes toward risk. Subjects in the experiment encountered an uncertain risk of experiencing a negative income shock over multiple periods and were able to purchase insurance at the start of each period. Subjects engaged in greater risk taking, insuring less frequently, when faced with the same risk over multiple periods. Subjects weighted experienced outcomes proportionately, in a manner consistent with rational Bayesian inference and contrary to the theory that individuals exhibit recency bias. On the other hand, subjects assigned a greater weight to outcomes that directly impacted their earnings compared to observed outcomes that had no effect on income. Unexplained autocorrelation across subjects’ choices suggests that inertia also plays an important role in repeated risk settings. I explore the relevance of these findings to public policy aimed at influencing market outcomes in the presence of infrequent environmental hazards.     

Violations of Present-Value Maximization in Income Choice

We report results of an experiment testing for present-value maximization in intertemporal income choice. Two-thirds of subjects did not maximize present value. Through a series of experimental manipulations that impose costs on non-present value maximizers, we are able to reduce the level of violations substantially. We find, however, that a sizeable proportion of subjects continue to systematically violate present-value principles. Our interpretation is that these subjects either cannot or choose not to distinguish between t income and t expenditure in making their choices. Self-management, bounded rationality, and sequence preference are suggested as possible explanations for such behavior.     

Prosocial risk taking and interpersonal regret in children: An individual differences study

The relations between prosocial risk taking (taking a risk to benefit another person; PSRT) and interpersonal regret (regret that one's choices have caused a poor outcome for another person) were examined in 192 children aged 7–9. PSRT was measured by children's choices within a gambling task in which one choice guaranteed participants a good prize whereas the other involved risking this prize to help a peer also win a good prize. Interpersonal regret was assessed within the same task by examining children's change in emotion when they learned they would have won a better prize for a peer had they chosen differently. Performance on this task was also examined in relation to sympathy and resource sharing. Findings indicated that the operationalizations of PSRT and interpersonal regret were meaningful. Children who took a prosocial risk were more generous in a resource sharing task. In some circumstances, children who took a prosocial risk were also more likely to experience interpersonal regret than those who did not take a prosocial risk, indicating that experiencing interpersonal regret may be related to individual differences in prosociality. However, experiencing interpersonal regret did not have a direct effect on subsequent prosocial behavior, when measured by resource sharing. We consider findings in relation to a possible distinction between outcome and process regret and the generalizability of the behavioral consequences of regret.     

Learning under compound risk vs. learning under ambiguity – an experiment

We design and conduct an economic experiment to investigate the learning process of agents under compound risk and under ambiguity. We gather data for subjects choosing between lotteries involving risky and ambiguous urns. Agents make decisions in conjunction with a sequence of random draws with replacement, allowing us to estimate the agents’ beliefs at different moments in time. For each type of urn, we estimate a behavioral model for which the standard Bayesian updating model is a particular case. Our findings suggest an important difference in updating behavior between risky and ambiguous environments. Specifically, even after controlling for the initial prior, we find that when learning under ambiguity, subjects significantly overweight the new signal, while when learning under compound risk, subjects are essentially Bayesian.     

Effects of Outcome and Probabilistic Ambiguity on Managerial Choices

Information ambiguity is prevalent in organizations and likely influences management decisions. This study examines, given imprecise probabilities and outcomes, how managers make choices when they are provided with single-figure benchmarks. Seventy-nine MBA students completed two experiments. We found that, in a decision framed as a decision under certainty involving an ambiguous outcome, the majority of the subjects were ambiguity prone in the loss condition and switched to ambiguity aversion in the gain condition. However, in the presence of probabilistic ambiguity in a decision under risk, this expected switching pattern was shown only when the difference in riskiness between the two choice options (in the loss condition) was perceived to be relatively small. In a companion study, we used a written protocol approach to identify factors that affect decision makers' investment choices when faced with ambiguous outcomes. Protocols frequently mentioned that the ambiguous outcome option was risky, even in the case which was framed as a decision under certainty in the problem statement. In a decision under risk with ambiguous outcomes, the combination of probabilistic risk and outcome ambiguity was seen as even more risky.