Appendix 1—figure 10. Trade-off between parametric drug effects on averaged preferential model-free credit assignment (aPMFCA) and model-based credit assignment (MBCA).

Based on our parameter recovery simulations (see Appendix 1—figure 9), we also calculated for each participant and each simulation estimation errors (est errors) for drug effects on aPMFCA and MBCA (as differences between fitted and generating drug effects). Next for each simulation index (i = 1,2,…,1000) we calculated the group-level Spearman correlation between these two estimation errors. The histogram of these correlations is plotted. There is weak negative trade-off between estimation errors of drug effects on aPMFCA and MBCA. Importantly, the negative empirical correlation (vertical black line) was still significant even after controlling for this trade-off (p = 0.03; calculated as the proportion of simulations with correlation ≤ empirical correlation).