Fig. 3.

Optimal actions for single and mixed difficulty tasks. The inter-trial intervals used for computing all three policies are D _C = D _I = 150. a Single difficulty task with up-probability for each decision drawn from u ∈{0.30,0.70}; b Single difficulty task with $u=\frac{1}{2}$; c Mixed difficulty task with u ∈{0.30,0.50,0.70}, with both easy and difficult trials equally likely, i.e., $\mathbb{P}(U\in {\mathcal{U}}_e)=\frac{1}{2}$