Reward context determines risky choice in pigeons and humans

Whereas humans are risk averse for monetary gains, other animals can be risk seeking for food rewards, especially when faced with variable delays or under significant deprivation. A key difference between these findings is that humans are often explicitly told about the risky options, whereas non-human animals must learn about them from their own experience. We tested pigeons (Columba livia) and humans in formally identical choice tasks where all outcomes were learned from experience. Both species were more risk seeking for larger rewards than for smaller ones. The data suggest that the largest and smallest rewards experienced are overweighted in risky choice. This observed bias towards extreme outcomes represents a key step towards a consilience of these two disparate literatures, identifying common features that drive risky choice across phyla

The power of nothing : risk preference in pigeons, but not people, is driven primarily by avoidance of zero outcomes

When making risky decisions, people and pigeons often show similar choice patterns. When people learn the reward probabilities through repeated exposure to the outcomes, their preference is disproportionately influenced by the extreme (highest and lowest) outcomes occurring in the decision context. Overweighting of these extremes increases preference for risky alternatives that lead to the highest outcome and decreases preference for risky alternatives that lead to the lowest outcome, termed the extreme-outcome rule. This rule predicts greater risk seeking for choices between safe and risky high-value outcomes than for choices between safe and risky low-value outcomes, when both choices occur in the same context. In a series of studies, we examine how this extreme-outcome rule generalizes within and across two evolutionary distant species: pigeons (Columba livia) and humans (Homo sapiens). Both species showed risky choices consistent with the extreme-outcome rule when a low-value risky option could yield an outcome of zero. When all outcome values were increased such that none of the options could lead to zero, people but not pigeons were still consistent with the extreme-outcome rule. Unlike people, pigeons no longer avoided a low-value risky option when it yielded a non-zero food outcome. These results suggest that, despite some similarities, different mechanisms underlie risky choice in pigeons and people

The power of nothing: Risk preference in pigeons, but not people, is driven primarily by avoidance of zero outcomes

Both human and non-human animals regularly need to make choices where the outcomes of their actions are unpredictable or probabilistic in some way. These are often termed “risky” choices. Faced with uncertain rewards, people (Homo sapiens) and pigeons (Columba livia) often show similar choice patterns. When the reward probabilities of risky choices are learned through experience, preferences in both species seem to be disproportionately influenced by the extreme (highest and lowest) outcomes in the decision context. Overweighting of these extremes increases preference for risky alternatives that lead to the highest outcome and decreases preference for risky alternatives that lead to the lowest outcome. In a series of studies, we systematically examine how this overweighting of extreme outcomes in risky choice generalizes across two evolutionary distant species: pigeons and humans. Both species showed risky choices consistent with an overweighting of extreme outcomes when the low-value risky option could yield an outcome of zero. When all outcome values were increased such that none of the options could lead to zero, people but not pigeons still overweighted the extremes. Unlike people, pigeons no longer avoided a low-value risky option when it yielded a non-zero food outcome. These results suggest that, despite some similarities, different mechanisms underlie risky choice in pigeons and people

Data from: Reward context determines risky choice in pigeons and humans

The data are compressed in a .zip format containing two comma separated (.csv) files. One file contains data from the human subjects and the other contains the data from the pigeon subjects. The files are labelled "human_data.csv" and "pigeon_data.csv", respectively, and are both in a spreadsheet format. The human subject data was sampled from University of Alberta introductory psychology students participating for course credit and a cash bonus. All human data was presented and scored using E-Prime 2.0 Professional Software. The pigeon subject data was scored by hand using closed circuit recorded video. The column labelled "Notes" corresponds to additional information provided by the various volunteer research assistants who participated in the running and scoring of the pigeon subjects

Forced-Exposure Trials and Suboptimal Choice Data and Code Repository

Repository for the data, code, and analysis of the manuscript "Forced-exposure trials increase suboptimal choice": https://doi.org/10.3758/s13423-022-02092-