BIC measures are summed across the 30 subjects. Parameters per subject are across both placebo and l-DOPA sessions. All models include separate parameters for placebo and l-DOPA sessions that capture the weighting of losses relative to equivalent gains (loss aversion, λ), risk aversion in the gain domain (α_gain), and risk aversion in the loss domain (α_loss). All models except the dual-inverse-temperature model included a shared parameter across sessions for stochasticity in choice (inverse temperature, μ). The final column is the difference between the model BIC and BICa-a, the BIC for the approach–avoidance model. The approach–avoidance model was preferred (lower BIC) to the prospect theory model, dual-inverse-temperature model, and gain-loss learning model. The more complex approach-avoidance-mixed model included additional approach–avoidance parameters for the mixed trials and had the lowest BIC of the models tested.