. Author manuscript; available in PMC: 2018 Jul 3.

Published in final edited form as: Prog Neuropsychopharmacol Biol Psychiatry. 2017 Apr 12;77:178–184. doi: 10.1016/j.pnpbp.2017.03.027

Table 1.

Illustration of the VR schedules of reinforcement.

VR Schedule of Reinforcement	Number of Lever Presses to Receive Large Reinforcer
VR6	1, 3, 6, 9, or 11
VR8	1, 3, 8, 13, or 15
VR10	1, 5, 10, 15, or 19
VR12	1, 7, 12, 17, or 23
VR15	1, 8, 15, 22, or 29
VR18	1, 9, 18, 27, or 35