Shull, R. L., Gaynor, S. T., & Grimes, J. A. (2001).
Response rate viewed as engagement bouts: Effects of relative reinforcement and schedule type.
Journal of the Experimental Analysis of Behavior,
75, 247-274.
The rate of a reinforced response is conceptualized as a
composite of engagement bouts (visits) and responding during
visits. Part 1 of this paper describes a method for estimating
the rate of visit initiations and the average number of responses
per visit from log survivor plots: the proportion of
interresponse times (IRTs) longer than some elapsed time (log
scale) plotted as a function of elapsed time. In Part 2 the
method is applied to IRT distributions from rats that obtained
food pellets by nose poking a lighted key under various multiple
schedules of reinforcement. As expected, total response rate
increased as a function of (a) increasing the rate of
reinforcement (i.e., variable-interval [VI] 4 min vs. VI 1 min),
(b) increasing the amount of the reinforcer (one food pellet vs.
four pellets), (c) increasing the percentage of reinforcers that
were contingent on nose poking (25% vs. 100%), and (d) requiring
additional responses after the end of the VI schedule (i.e.,
adding a tandem variable-ratio [VR] 9 requirement). The first
three of these variables (relative reinforcement) increased the
visit-initiation rate. The tandem VR, in contrast, increased the
number of responses per visit. Thus, variables that have similar
effects on total response rate can be differentiated based on
their effects on the components of response rate.
Key words: response rate, visits, bouts, relative reinforcement,
tandem variable ratio, key poke, rats