When making decisions involving risky outcomes on the basis of verbal descriptions of the outcomes and their associated probabilities, people behave as if they overweight small probabilities. In contrast, when the same outcomes are instead experienced in a series of samples, people behave as if they underweight small probabilities. We present two experiments showing that the existing explanations of the underweighting observed in decisions from experience are not sufficient to account for the effect. Underweighting was observed when participants experienced representative samples of events, so it cannot be attributed to undersampling of the small probabilities. In addition, earlier samples predicted decisions just as well as later samples did, so underweighting cannot be attributed to recency weighting. Finally, frequency judgments were accurate, so underweighting cannot be attributed to judgment error. Furthermore, we show that the underweighting of small probabilities is also reflected in the bestfitting parameter values obtained when prospect theory, the dominant model of risky choice, is applied to the data.

How different are £0.50 and £1.50, “a small chance” and “a good chance,” or “three months” and “nine months”? Our studies show that people behave as if the differences between these values are altered by incidental everyday experiences. Preference for a £1.50 lottery rather than a £0.50 lottery was stronger among individuals exposed to intermediate supermarket prices than among those exposed to lower or higher prices. Preference for “a good chance” rather than “a small chance” of winning a lottery was stronger among participants who predicted intermediate probabilities of rain than among those who predicted lower or higher chances of rain. Preference for consumption in “three months” rather than “nine months” was stronger among participants who planned for an intermediate birthday than among participants who planned for a sooner or later birthday. These fluctuations directly challenge economic accounts that translate monies, risks, and delays into subjective equivalents with stable functions. The decision-by-sampling model—in which subjective values are rank positions constructed from comparisons with samples—predicts these effects and indicates a primary role for sampling in decision making.

Every attribute can be expressed in multiple ways. For example, car fuel economy can be expressed as fuel efficiency (“miles per gallon”), fuel cost in dollars, or tons of greenhouse gases emitted. Each expression, or “translation,” highlights a different aspect of the same attribute. We describe a new mechanism whereby translated attributes can serve as decision “signposts” because they (1) activate otherwise dormant objectives, such as proenvironmental values and goals, and (2) direct the person toward the option that best achieves the activated objective. Across three experiments, we provide evidence for the occurrence of such signpost effects as well as the underlying psychological mechanism. We demonstrate that expressing an attribute such as fuel economy in terms of multiple translations can increase preference for the option that is better aligned with objectives congruent with this attribute (e.g., the more fuel-efficient car for those with proenvironmental attitudes), even when the new information is derivable from other known attributes. We discuss how using translated attributes appropriately can help align a person’s choices with their personal objectives. The online appendix is available at https://doi.org/10.1287/mnsc.2016.2703 . This paper was accepted by Yuval Rottenstreich, judgment and decision making.

Using capture-recapture analysis we estimate the effective size of the active Amazon Mechanical Turk (MTurk) population that a typical laboratory can access to be about 7,300 workers. We also estimate that the time taken for half of the workers to leave the MTurk pool and be replaced is about 7 months. Each laboratory has its own population pool which overlaps, often extensively, with the hundreds of other laboratories using MTurk. Our estimate is based on a sample of 114,460 completed sessions from 33,408 unique participants and 689 sessions across seven laboratories in the US, Europe, and Australia from January 2012 to March 2015.

Transitivity is the assumption that if a person prefers A to B and B to C, then that person should prefer A to C. This article explores a paradigm in which Birnbaum, Patton and Lott (1999) thought people might be systematically intransitive. Many undergraduates choose C = ($96, .85; $90, .05; $12, .10) over A = ($96, .9; $14, .05; $12, .05), violating dominance. Perhaps people would detect dominance in simpler choices, such as A versus B = ($96, .9; $12, .10) and B versus C, and yet continue to violate it in the choice between A and C, which would violate transitivity. In this study we apply a true and error model to test intransitive preferences predicted by a partially effective editing mechanism. The results replicated previous findings quite well; however, the true and error model indicated that very few, if any, participants exhibited true intransitive preferences. In addition, violations of stochastic dominance showed a strong and systematic decrease in prevalence over time and violated response independence, thus violating key assumptions of standard random preference models for analysis of transitivity.