See erratum, JEAB, 2002, 78, 94.
Baron, A., & Derenne, A. (2000).
Progressive-ratio schedules: Effects of later schedule requirements on earlier performances.
Journal of the Experimental Analysis of Behavior,
73, 291-304.
Four rats were studied with variants of a progressive-ratio
schedule with a step size of 6 in which different terminal
components followed completion of the 20th ratio: (a) a reversal
of the progression, (b) a fixed-ratio 6 schedule, or (c)
extinction. Responding in the progressive-ratio components of
these schedules was compared to performances under conventional
progressive- ratio baselines. Under baseline conditions,
postreinforcement pauses increased exponentially as a function of
increasing ratio size, whereas running rates showed modest
declines. The procedure of linking the progressive- ratio
schedule to the reversed progression or to the fixed-ratio
component resulted in decreased pausing. Linking the
progressive-ratio schedule to the extinction component had the
opposite effect, that of producing weakened progressive-ratio
performances as evidenced by increased pausing. Subjects whose
responses were reinforced on half of the ratios also showed
exponential increases; however, pauses were substantially shorter
following ratios on which the reinforcer was omitted. The results
suggested that progressive-ratio pausing reflects the influence
of remote as well as local contingencies.
Key words: progressive-ratio schedule, fixed-ratio schedule,
postreinforcement pause, running rate, multiple schedule of
reinforcement, lever press, rats