A parallel accumulator model accounts for decision randomness when deciding on risky prospects with different expected value
Howlett, Jonathon; Paulus, Martin (2020), A parallel accumulator model accounts for decision randomness when deciding on risky prospects with different expected value, Dryad, Dataset, https://doi.org/10.6075/J0F76B26
Forty-four college students (age: 19.34 ± 2.28 years; 26 females and 18 males) participated in this study. Subjects were recruited from San Diego State University through an online system as part of Psychology 101 class during the spring of 2013. They were contacted and scheduled for an experimental session during winter quarter 2013. The study was approved by the Human Research Protections Program at San Diego State University. All participants provided written informed consent, and were compensated $25 and 2.5 course credits for completing the study. Prior to completing the experimental task, participants completed the State-Trait Anxiety Inventory, Trait scale (STAI-T) to assess trait anxiety.
Subjects completed a decision-making task consisting of 4 blocks with 24 trials per block. On each trial, subjects were asked to choose one of two gambles. They were asked to imagine they were choosing between two different random drawings with different numbers of chips worth 0, 20, or 40 points (subjects played for virtual points rather than real money). For each of the two options, subjects were shown the number of each type of chip (out of a total of 100). Subjects were thereby shown the value and probability of each possible outcome. There were four different stimuli (i.e. four different drawings) used in the task with different risk and expected value (EV) profiles: high risk/high EV, high risk/low EV, low risk/high EV, and low risk/low EV. High risk gambles had variance 384 (with larger numbers of 0-point and 40-point chips), while low risk gambles had variance 96 (with larger number of 20-point chips). High EV gambles had EV of 24 points, while low EV gambles had EV of 20 points. With 4 different stimuli, there were 6 different possible pairs of stimuli, each of which was encountered 16 times during the course of the task (subjects were never asked to choose between two identical stimuli). After making a selection, subjects were shown the outcome of their choice (either 0, 20, or 40 points, which was determined by a random number generator in accordance with the stated probabilities). Half of blocks were “Counterfactual Feedback” blocks, in which subjects were shown what they would have received if they had made the opposite choice. The other half were “No Counterfactual Feedback” blocks, in which subjects were not shown the outcome of the opposite choice. The order of “Counterfactual Feedback” and “No Counterfactual Feedback” blocks was counterbalanced between subjects. After receiving feedback, subjects were asked to indicate their level of satisfaction with their choice on a visual analog scale.
STAIT: State-Trait Anxiety Inventory, Trait scale score
Condition: "single" refers to "No Counterfactual Feedback", "double" refers to "Counterfactual Feedback"
EV, AltEV, Risk, AltRisk: EV and Risk refer to the option that was chosen, while AltEV and AltRisk refer to the option that was not chosen
Actual: Points received
Counterfactual: Points that would have been received from the alternative choice (shown to subjects in "Counterfactual Feedback" blocks)
Satisfaction: Visual Analog Scale rating by subject
ReactionTime: In seconds
Trial: Trial number within block
TrialTot: Trial number for entire task
National Institute of Mental Health, Award: 5T32MH018399-28
National Institute on Drug Abuse, Award: R01- DA016663
National Institute on Drug Abuse, Award: P20-DA027834
National Institute on Drug Abuse, Award: R01-DA027797
National Institute on Drug Abuse, Award: R01-DA018307