Fig. 9.

Optimal policy during mixed difficulty trials with biased prior beliefs. For all computations, the mixture of drifts involves 𝜖 _e = 0.20, 𝜖 _d = 0 and $\mathbb{P}(U\in {\mathcal{U}}_e)=\frac{1}{2}$. Three different priors are used: the left column uses $\mathbb{P}(U\in {\mathcal{U}}_{+})=0.52$, the middle column uses $\mathbb{P}(U\in {\mathcal{U}}_{+})=0.55$, and the right column uses $\mathbb{P}(U\in {\mathcal{U}}_{+})=0.70$. The first row shows optimal policies, the second row shows the posterior probability for the trial being easy given the state and the third row shows the posterior probability for the trial having up-probability > 0.50 given the state. For all three computations, the inter-trial intervals are D _C = D _I = 150