the rat Gambling Task.

(A) Schematic of the cued rGT. A nose poke response in the food tray extinguished the traylight and initiated a new trial. After an inter-trial interval (ITI) of 5 s, four stimulus lights were turned on in holes 1, 2, 4, and 5, each of which was associated with a different number of sugar pellets. The order of the options from left to right was counter-balanced within each cohort to avoid development of a simple side bias (version A (shown): P1, P4, P3, P2; version B: P4, P1, P3, P2). The animal was required to respond at a hole within 10 s. This response was then rewarded or punished depending on the reinforcement schedule for that option. If the animal lost, the stimulus light in the chosen hole flashed at a frequency of 0.5 Hz for the duration of the time-out penalty, and all other lights were extinguished. The maximum number of pellets available per 30 min session shows that P1 and P2 are more optimal than P3 and P4. The percent choice of the different options is one of the primary dependent variables. A score variable is also calculated, as for the IGT, to determine the overall level of risky choice as follows: [(P1 + P2) – (P3 + P4)]. Figure is modified from Winstanley & Floresco (2016). (B) Distinct variants of the rGT. On the uncued variant, no audiovisual cues were present. The standard task featured audiovisual cues that scaled in complexity and magnitude with reward size. The reverse-cued variant inverted this relationship, such that the simplest cue was paired with the largest reward, and vice versa. Audiovisual cues were paired with both wins and losses for the outcome-cued variant. For the random-cued variant, cues were played on 50% of trials, regardless of outcome. Lastly, for the loss-cued variant, cues were only paired with losing outcomes, at the onset of the time-out penalty.

Differences in baseline performance between task variants.

Comparative baseline performance on variants of the rGT. (A) Percent choice of each option in the six rGT task variants. (B) Average risk score shows risk preference is significantly modulated by the presence and contingency of outcome-paired cues, with preference for the high-risk options (P3 and P4) strongly enhanced in task variants in which the audiovisual cues scale with outcome magnitude and occur on winning trials. (C) Premature responding across the rGT variants, and (D) for risky versus optimal decision-makers. (E) Latency for reward collection on winning trials across the variants of the rGT. Data are expressed as mean + SEM.

P1-P4 choice comparisons

Comparisons of P1-P4 between task variants using Tukey’s honest significant differences (HSD) test. Bolded values indicate a significant difference.

Risk score comparisons

Comparisons of risk score between task variants using Tukey’s HSD test. Bolded values indicate a significant difference.

Premature responding comparisons

Comparisons of premature responding between task variants using Tukey’s HSD test. Bolded values indicate a significant difference.

Collect latency comparisons

Comparisons of collect latency between task variants using Tukey’s HSD test. Bolded values indicate a significant difference.

Devaluation in risk-preferring rats: P1-P4 choice

choice x devaluation interactions for each task in risk-preferring rats. Bolded values indicate a significant difference.

Effects of sucrose pellet devaluation on choice preference.

(A) P1-P4 choice preference after reinforcer devaluation compared to baseline preference for risk-preferring rats. Devaluation did not shift choice patterns selectively in task variants featuring consistent win-paired cues (standard, outcome-cued, reverse-cued). (B) P1-P4 choice preference after reinforcer devaluation compared to baseline preference in optimal rats. Reinforcer devaluation induced a slight shift in choice preference, with no differences found between tasks. Data are expressed as the mean change in % choice from baseline + SEM to highlight effects independent of differences in preference for each option between cohorts.

Devaluation in risk-preferring rats: Risk score

risk score x devaluation interactions for each task in risk-preferring rats. Bolded values indicate a significant difference.

Difference in WAIC between each model and the nonlinear model for each of the rGT task variants. Lower WAIC indicates a better explanation of the data. Error bars are SEM.

Average risk score (sessions 18-20) for the nonlinear and scaled + offset models simulated with the subject-level parameter estimates for each task variant.

Group-level posterior estimates of nonlinear cost model parameters. Asterisks within the inset tables mark parameters for which the 95% HDI of the sample difference did not contain zero, indicating a credible difference. For each distribution, the line demarcates the means, the box demarcates the interquartile interval, and the whiskers demarcate the 95% HDI.

Group-level posterior estimates of scaled + offset model parameters. Asterisks within the inset tables mark parameters for which the 95% HDI of the sample difference did not contain zero, indicating a credible difference. For each distribution, the line demarcates the means, the box demarcates the interquartile interval, and the whiskers demarcate the 95% HDI.

Nonlinear model simulated risk score comparisons

Comparisons of risk scores simulated from nonlinear model subject-level parameter estimates using Tukey’s HSD test. Bolded values indicate a significant difference, italicized values indicate a trending difference.

Scaled + offset model simulated risk score comparisons

Comparisons of risk scores simulated from scaled + offset model subject-level parameter estimates using Tukey’s HSD test. Bolded values indicate a significant difference.

Group-level posterior estimates of basic model parameters. Asterisks within the inset tables mark parameters for which the 95% HDI of the sample difference did not contain zero, indicating a credible difference. For each distribution, the box demarcates the interquartile interval and the whiskers demarcate the 95% HDI.