Touchscreen-based cognitive bias paradigm. Mice were trained to distinguish between bars displayed at the top (negative condition) or bottom (positive condition) of a central field of a touchscreen. In this example, mice learned to touch right for a large reward during the positive condition and to touch left for a small reward during the negative condition (the association between positive/negative cue and the correct touch side was counterbalanced across mice). During the test, mice were presented with cues displayed at three intermediate positions: near positive, middle and near negative. The relative number of “optimistic”-like responses to these ambiguous conditions served as outcome measures of the animals’ cognitive judgement bias. Figure adopted from Krakenberg et al. (2019) with permission from Elsevier36.