Figure 2.

Different schedules of reinforcement produce different predisposition to habit formation in C57Bl6/J mice. (A) Acquisition of the lever pressing task in animals trained on random ratio and random interval schedules. The rate of lever pressing (per minute) for each daily session is depicted. (B) Average rate of head entry throughout training for the random interval and random ratio groups. (C) Rate of reinforcement per lever press throughout training for the random interval and random ratio groups. (D) Lever pressing during the valued versus the devalued condition for the different training schedules, normalized to the lever pressing of the last day of training. (E) Lever pressing on the training lever versus a novel lever for the different training schedules, normalized to the lever pressing of the last day of training.