title: Concurrent progressive ratio schedules: Effects of reinforcer probability on breakpoint and response allocation.
abstract: Although progressive ratio (PR) schedules have been used to explore effects of a range of reinforcer parameters (e.g., magnitude, delay), effects of reinforcer probability remain underexplored. The present project used independently progressing concurrent PR PR schedules to examine effects of reinforcer probability on PR breakpoint (highest completed ratio prior to a session terminating 300s pause) and response allocation. The probability of reinforcement on one lever remained at 100% across all conditions while the probability of reinforcement on the other lever was systematically manipulated (i.e., 100%, 50%, 25%, 12.5%, and a replication of 25%). Breakpoints systematically decreased with decreasing reinforcer probabilities while breakpoints on the control lever remained unchanged. Patterns of switching between the two levers were well described by a choice-by-choice unit price model that accounted for the hyperbolic discounting of the value of probabilistic reinforcers.
authors.affiliation: University of Kansas, Department of Applied Behavioral Science, United States; University of Kansas, Problem Gambling Research and Education Support System, United States. Electronic address: dpj@ku.edu.
authors.forename: David P
authors.initials: DP
authors.lastname: Jarmolowicz
authors.affiliation: University of Kansas, Department of Applied Behavioral Science, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sofis
authors.affiliation: University of Kansas, Department of Applied Behavioral Science, United States.
authors.forename: Alexandria C
authors.initials: AC
authors.lastname: Darden
mesh_terms: D000818:Animals; D002755:Choice Behavior; D003216:Conditioning, Operant; D008297:Male; D011336:Probability; D051381:Rats; D012055:Reinforcement Schedule
keywords: Choice; Probabilistic; Progressive ratio; Rat; Unit price