Fig. 1.

Responding during discrimination training (left panels) and extinction testing (right panels) in the Thrailkill et al. (2018) experiment described in the text. For Group CRF (continuous reinforcement, upper panels), the instrumental response was reinforced in every presentation of the discriminative stimulus (a 30-s tone), whereas in Group PRF (partial reinforcement, lower panels) it was reinforced in only half the stimulus presentations. The lowest lines in all panels indicate baseline responding outside the tone. In the extinction tests (right), responding in Group CRF was not suppressed by devaluation of the reinforcer through taste aversion conditioning (Group Paired), suggesting habit. In contrast, responding in Group PRF was suppressed by devaluation, indicating goal-directed action. Reprinted with permission of the publisher