4.3.1 Bias effect and clinical scores

In the non-social motor task, neither the SANS, the SAPS, or the disorganization scores were found to be predicted by the Bias effect. In the non-social superordinate task, the Bias effect significantly predicted the disorganization score (R2=0.21, p=.04), and the SAPS score (R2=0.39, p=.003) (figure 8, a. and b.). The more patients were disorganized and exhibited positive symptoms, the higher was the Bias effect on their performances, i.e. the more they relied on their priors to make their decision.

In the social motor task, the Bias effect was found to significantly predict the SANS score (R2=0.22, p=.03), while in the social superordinate task, the Bias effect also predicted the SANS score (R2=0.32, p=.008) (figure 8, c. and d.) and tended to explain a part of the variance in the disorganization score (R2=0.18, p=.09). Thus, the more patients exhibited negative symptoms, the smaller was the Bias effect on their performances, i.e. the less they relied on their priors when inferring intentions accomplished in a context of social interaction.

Fig. 8. The linear regression lines derived from the linear regressions analyses between the Bias effect (explanatory factor) and patients’ disorganization score (a), positive (b) and negative symptoms (c,d) are shown in red. The 95% confidence intervals around the regression lines are shown in grey.