Fig. 2.

Responding during extinction testing in the Thrailkill et al. (2021) experiments described in the text. For Group CRF (continuous reinforcement), the instrumental response had been reinforced in every presentation of the discriminative stimulus (a brief 6-s tone), whereas in Group PRF (partial reinforcement) it had been reinforced in only half of the stimulus presentations. Responding in Group CRF was not suppressed by separate taste aversion conditioning of the reinforcer (Group Paired), indicating habit; in contrast, responding in Group PRF was suppressed, indicating goal-directed action. “pre” indicates baseline responding outside the tone. Adapted from Thrailkill et al. (2021) and used with permission of the publisher