Evidence for positive, but not negative, behavioral contrast with wheel-running reinforcement on multiple variable-ratio schedules.
Rats responded on a multiple variable-ratio (VR) 10 VR 10 schedule of reinforcement in which lever pressing was reinforced by the opportunity to run in a wheel for 30s in both the changed (manipulated) and unchanged components. To generate positive contrast, the schedule of reinforcement in the changed component was shifted to extinction; to generate negative contrast, the schedule was shifted to VR 3. With the shift to extinction in the changed component, wheel-running and local lever-pressing rates increased in the unchanged component, a result supporting positive contrast; however, the shift to a VR 3 schedule in the changed component showed no evidence of negative contrast in the unaltered setting, only wheel running decreased in the unchanged component. Changes in wheel-running rates across components were consistent in showing a compensation effect, depending on whether the schedule manipulation increased or decreased opportunities for wheel running in the changed component. These findings are the first to demonstrate positive behavioral contrast on a multiple schedule with wheel running as reinforcement in both components.
Mount Allison University, Sackville, New Brunswick, Canada. Electronic address: tbelke@mta.ca.
Terry W
TW
Belke
University of Alberta, Edmonton, Alberta, Canada.
W David
WD
Pierce
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D003216:Conditioning, Operant / Q000502:physiology*; D005260:Female; D051381:Rats; D020318:Rats, Long-Evans; D012055:Reinforcement Schedule; D012420:Running / Q000502:physiology* / Q000523:psychology
Behavioral contrast; Lever pressing; Multiple schedule; Rats; Variable ratio; Wheel-running reinforcement