Fig. 3: Influence of haloperidol on the winning model.
a, Bayesian t-test results (n = 28) assessing the difference and uncertainty (median ± 95% HDI) of the change in mean parameter estimates (∆μ; difference in mean) between placebo and haloperidol. Red distributions indicate that the 95% high-density interval (HDI) does not cross 0, suggesting reasonable certainty that the mean difference is not an artefact of statistical noise. The d values indicate the median effect size (Cohen’s d; Supplementary Fig. 4). The red box indicates the parameters where the effect size distributions were most robust, where the 95% HDI lay outside of the region of probable equivalence with the null hypothesis. b, Simulations (±s.e.m.) of the marginal effect of likelihood parameters on the precision (1/σ2; inverse variance) of harmful intent (red) and self-interest (black) attributions over all trials, controlling for Dictator style. Vertical lines are indicative of the median individual parameter estimates from both haloperidol and placebo groups. The blue arrow indicates the difference from placebo to haloperidol (see Supplementary Fig. 3 for trial-wise and within-Dictator precision changes). Simulations are consistent with the notion that wHI increases flexibility within and between contexts, accentuating smooth learning. Note that there was no significant correlation between w0, wSI and wHI in our parameter estimation from our real data (all P-values > 0.05; Supplementary Fig. 2), suggesting independent contributions from each to the attributional dynamics. c, Factor loading of each parameter on flexibility (factor 1) and learning (factor 2) dimensions. A loading filter of |0.4| was applied. Both of these factors can discriminate effectively between drug conditions. The wSI term is not featured in this plot as it was not meaningfully loaded onto either factor. d, Factor scores (absolute value) for each individual participant (n = 28) for both haloperidol (red) and placebo (blue) conditions ordered from low to high. The panels on the right demonstrate the marginal loading across participants. e, Candyfloss plot factor scores for each individual participant. The grey lines indicate that the same participant was responsible for each connected point under placebo (blue) and haloperidol (red). f, Receiver operating characteristic describing the sensitivity and specificity of factors to differentiate drug conditions. Area under the curve = 0.91; sensitivity = 0.8; specificity = 0.78.
