This article extends computational models of schizophrenia that focus on the negative aspects of this syndrome to behavioral biases that are associated with a positive symptom of schizophrenia, namely delusions. The phenomenon studied is the "jump-to-conclusions" style of reasoning that is characterized by delusional patients-in comparison with controls-whereby they make less-informed decisions when an option to collect more decision-specific information is available. Simulations show that these differences can be min-ticked by modulating the gain parameter-associated with variations in dopamine level-in a simple network model.