Tanno, T., Silberberg, A. & Sakagami, T. (2009).
Single-sample discrimination of different schedules’ reinforced interresponse times.
Journal of the Experimental Analysis of Behavior, 91, 157-167.
Food-deprived rats in Experiment 1 responded to one of two tandem schedules that were, with equal
probability, associated with a sample lever. The tandem schedules’ initial links were different randominterval
schedules. Their values were adjusted to approximate equality in time to completing each
tandem schedule’s response requirements. The tandem schedules differed in their terminal links: One
reinforced short interresponse times; the other reinforced long ones. Tandem-schedule completion
presented two comparison levers, one of which was associated with each tandem schedule. Pressing the
lever associated with the sample-lever tandem schedule produced a food pellet. Pressing the other
produced a blackout. The difference between terminal-link reinforced interresponse times varied across
10-trial blocks within a session. Conditional-discrimination accuracy increased with the size of the
temporal difference between terminal-link reinforced interresponse times. In Experiment 2, one
tandem schedule was replaced by a random ratio, while the comparison schedule was either a tandem
schedule that only reinforced long interresponse times or a random-interval schedule. Again,
conditional-discrimination accuracy increased with the temporal difference between the two schedules’
reinforced interresponse times. Most rats mastered the discrimination between random ratio and
random interval, showing that the interresponse times reinforced by these schedules can serve to
discriminate between these schedules.
Key words: interresponse-time reinforcement, random interval, random ratio, variable interval,
variable ratio, rats, lever press