Disentangling the Roles of Approach, Activation and Valence in Instrumental and Pavlovian Responding
Figure 1
A: Instrumental training. To centre the cursor, subjects clicked in a central square. In approach trials (top), subjects chose whether to move the cursor towards the mushroom and click inside the blue frame onto the mushroom (go), or not do anything (nogo). In throwaway withdrawal trials (middle), they instead moved the cursor away from the mushroom and clicked in the empty blue frame (go) or did nothing (nogo). In release withdrawal trials (bottom), subjects were instructed to keep the button pressed after the initial click in the central square. The mushroom was then presented centrally, under the cursor. To throw away the mushroom, subjects released the button. Outcomes were presented immediately after go actions, or after 1.5 seconds. B: Pavlovian training. Subjects passively viewed stimuli and heard auditory tones, followed by wins and losses. C: On Pavlovian query trials, subjects chose between two Pavlovian stimuli. No outcomes were presented, but they were counted and added to the total presented at the end of the experiment. D: Pavlovian-instrumental transfer. Subjects responded to instrumental stimuli with Pavlovian stimuli tiling the background. No outcomes were presented, but subjects were instructed that their choices counted towards the final total. No explicit instructions about the contribution of Pavlovian stimuli towards the final total were given.