Model evidence for the mismatch and omission effects. A, B, Left, Relative log-evidence and results of FFX BMS over the DCMs in their ability to model the mismatch effect ERP contrast in the attend-auditory and attend-visual conditions, respectively (Fig. 2, left panels). *The model with the highest log-evidence. The difference between log-evidence of models with highest and second-highest evidence (ΔF) is shown in each case. A ΔF of 5 is equivalent to a Bayes factor of 150 in favor of the winning model. C, D, Left, Log-evidence of the same DCMs, but for modeling the omission effect ERP contrast in the attend-auditory and attend-visual conditions (Fig. 2, right panels). Among the DCMs instantiated and tested (Fig. 4), model M6 (B, right) was the winning model of the mismatch effect (A, right), whereas model M18 (D, right) was the winning model of the omission effect (C, right), in both attention conditions. For connections in the winning models that were significantly modulated by these effects in each attention condition, the posterior expectations of the strength of this modulation calculated with BMA are indicated alongside.