Lottery Choice Task Research Articles

Is there selection bias in laboratory experiments? The case of social and risk preferences

Laboratory experiments are frequently used to examine the nature of individuals’ social and risk preferences and inform economic theory. However, it is unknown whether the preferences of volunteer participants are representative of the population from which the participants are drawn, or whether they differ due to selection bias. To answer this question, we measured the preferences of 1,173 students in a classroom experiment using a trust game and a lottery choice task. Separately, we invited all students to participate in a laboratory experiment using common recruitment procedures. To evaluate whether there is selection bias, we compare the social and risk preferences of students who eventually participated in a laboratory experiment to those who did not, and find that they do not differ significantly. However, we also find that people who sent less in a trust game were more likely to participate in a laboratory experiment, and discuss possible explanations for this behavior.

Differences in risk aversion between young and older adults

Research on decision-making strategies among younger and older adults suggests that older adults may be more risk averse than younger people in the case of potential losses. These results mostly come from experimental studies involving gambling paradigms. Since these paradigms involve substantial demands on memory and learning, differences in risk aversion or other features of decision-making attributed to age may in fact reflect age-related declines in cognitive abilities. In the current study, older and younger adults completed a simpler, paired lottery choice task used in the experimental economics literature to elicit risk aversion. A similar approach was used to elicit participants' discount rates. The older adult group was more risk averse than younger adults (p < .05) and also had a higher discount rate (15.6-21.0% vs. 10.3-15.5%, p < .01), indicating lower expected utility from future income. Risk aversion and implied discount rates were weakly correlated. It may be valuable to investigate developmental changes in neural correlates of decision-making across the lifespan.

Risk attitude elicitation using a multi-lottery choice task: Real vs. hypothetical incentives

ABSTRACTWe present a bi-dimensional multi lottery choice task which can be used in order to elicit the agents' risk attitudes in financial environments. This task is implemented both with hypothetical and real monetary incentives in a between-subjects and a within-subjects experiment. We observe choices involving significantly lower risk aversion on aggregate when incentives are real. The differences grow with the stakes at play. We also obtain significant differences between hypothetical and real rewards in both utility weighting and probability weighting estimated parameters. We find that the use of hypothetical incentives in multi-lottery choice tasks for evaluating individual risk aversion can be misleading.

Is There Selection Bias in Laboratory Experiments?

Do the social and risk preferences of participants in laboratory experiments represent the preferences of the population from which they are recruited? To answer this question, we conducted a classroom experiment with a population of 1,173 students using a trust game and a lottery choice task to measure individual preferences. Separately, all 1,173 students were invited to participate in a laboratory experiment. To determine whether selection bias exists, we compare the preferences of the individuals who eventually participated in a laboratory experiment to those in the population. We find that the social and risk preferences of the students participating in the laboratory experiment are not significantly different from the preferences of the population from which they were recruited. We further show that participation decisions across most subgroups (e.g., men vs. women) do not differ significantly. We therefore fail to find selection bias based on social and risk preferences.

Measuring Individual Risk Attitudes in the Lab: Task or Ask? An Empirical Comparison

This paper compares two prominent empirical measures of individual risk attitudes - the Holt and Laury (2002) lottery-choice task and the multi-item questionnaire advocated by Dohmen, Falk, Huffman, Schupp, Sunde and Wagner (forthcoming) - with respect to (a) their within-subject stability over time (one year) and (b) their correlation with actual risk-taking behaviour in the lab - here the amount sent in a trust game (Berg, Dickaut, McCabe, 1995). As it turns out, the measures themselves are uncorrelated (both times) and, most importantly, only the questionnaire measure exhibits test-re-test stability (r =.78), while virtually no such stability is found in the lottery-choice task. In addition, only the questionnaire measure shows the expected correlations with a Big Five personality measure and is correlated with actual risk-taking behaviour. The results suggest that the questionnaire is the more adequate measure of individual risk attitudes for the analysis of behaviour in economic (lab) experiments. Moreover, with respect to trust, the high re-test stability of trust transfers (r = .70) further supports the conjecture that trusting behaviour indeed has a component which itself is a stable individual characteristic (Glaeser, Laibson, Scheinkman and Soutter, 2000).

The effects of one night of sleep deprivation on known‐risk and ambiguous‐risk decisions

Sleep deprivation has been shown to alter decision-making abilities. The majority of research has utilized fairly complex tasks with the goal of emulating 'real-life' scenarios. Here, we use a Lottery Choice Task (LCT) which assesses risk and ambiguity preference for both decisions involving potential gains and those involving potential losses. We hypothesized that one night of sleep deprivation would make subjects more risk seeking in both gains and losses. Both a control group and an experimental group took the LCT on two consecutive days, with an intervening night of either sleep or sleep deprivation. The control group demonstrated that there was no effect of repeated administration of the LCT. For the experimental group, results showed significant interactions of night (normal sleep versus total sleep deprivation, TSD) by frame (gains versus losses), which demonstrate that following as little as 23 h of TSD, the prototypical response to decisions involving risk is altered. Following TSD, subjects were willing to take more risk than they ordinarily would when they were considering a gain, but less risk than they ordinarily would when they were considering a loss. For ambiguity preferences, there seems to be no direct effect of TSD. These findings suggest that, overall, risk preference is moderated by TSD, but whether an individual is willing to take more or less risk than when well-rested depends on whether the decision is framed in terms of gains or losses.

Direct and indirect effects of pathological gambling on risk attitudes

AbstractWe study individual decision making in a lottery-choice task performed by three different populations: gamblers under psychological treatment (“addicts”), gamblers’ spouses (“victims”), and people who are neither gamblers or gamblers’ spouses (“normals”). We find that addicts are willing to take less risk than normals, but the difference is smaller as a gambler’s time under treatment increases. The large majority of victims report themselves unwilling to take any risk at all. However, addicts in the first year of treatment react more than other addicts to the different values of the risk-return parameter.

Individual-Level Loss Aversion in Riskless and Risky Choices

Loss aversion can occur in riskless and risky choices. Yet, there is no evidence whether people who are loss averse in riskless choices are also loss averse in risky choices. We measure individual-level loss aversion in riskless choices in an endowment effect experiment by eliciting both WTA and WTP from each of our 360 subjects (randomly selected customers of a car manufacturer). All subjects also participate in a simple lottery choice task which arguably measures loss aversion in risky choices. We find substantial heterogeneity in both measures of loss aversion. Loss aversion in the riskless choice task and loss aversion in the risky choice task are highly significantly and strongly positively correlated. We find that in both choice tasks loss aversion increases in age, income, and wealth, and decreases in education.

Risk Aversion and Incentive Effects: Comment

Holt and Laury, AER 2002, develop an experimental design to determine the risk aversion of an individual. They use their observations to argue that increased incentives appear to change risk attitudes, leading to greater risk aversion. However, their main treatment, the effects of scaling up the stakes of the lottery choice task, is confounded by a simple order effect. We extend their design to test for these order effects, and show that they are indeed significant. The size of the stakes still affects measured risk aversion, but the effect is only one-half of the apparent effect when one does not control for task order.

Do players correctly estimate what others do?: Evidence of conservatism in beliefs

In a simple experimental environment a group of subjects was asked to give estimates of a second group’s choice frequencies in a set of lottery-choice tasks. The results show that subjects in the first group are on average able to correctly predict the option that is chosen with higher frequency by the second group, but the predictions are systematically inaccurate in that they are distorted toward the uniform prior. Two mechanisms to elicit the expectations were used in the experiment, a quadratic scoring rule and a bidding mechanism. Aggregate results being similar under both mechanisms, the use of the former mechanism consistently yields more accurate predictions.

Risk, complexity, and deviations from expected-value maximization: Results of a lottery choice experiment

Varying several parameters of single-stage lottery choice tasks we investigate the question which features of a decision task lead subjects to deviate from maximizing expected monetary value (EV). Despite small differences in EV between the two lotteries in the choice sets, the subjects on average chose the lottery with the higher EV in every task. Risk avoidance occurs, but not consistently over all tasks. Further results are that subjects prefer less complex lotteries over more complex ones, and that risk matters the more the less complex the decision task is.

MONEY DOES NOT INDUCE RISK NEUTRAL BEHAVIOR, BUT BINARY LOTTERIES DO EVEN WORSE

If payoffs are tickets for binary lotteries, which involve only two money prizes, then rationality requires expected value maximization in tickets. This payoff scheme was increasingly used to induce risk neutrality in experiments. The experiment presented here involved lottery choice and evaluation tasks. One subject group was paid in binary lottery tickets, another directly in money. Significantly greater deviations from risk neutral behavior are observed with binary lottery payoffs. This discrepancy increases when subjects have easy access to the alternatives' expected values and mean absolute deviations. Behavioral regularities are observed at least as often as with direct money payoffs.