Secondly, the computational approach specifies the process parameters of RL, such as PE, learning rate, reward sensitivity,and memory of previous reinforcement (which will be discussedb in detail below). For instance, in the field of depression, this reduces the broadly defined symptom of anhedonia to more specific and refined constructs (Treadway and Zald, 2011; Der-Avakianand Markou, 2012. See our later discussion of ‘wanting’, ‘liking’and learning in Section 3.4). This moves the field from general symptom-based descriptions to direct and precise identification of impaired latent functions (Wiecki et al., 2015).