Bruner, C. A., Avila S., R., Acuna, L., & Gallardo, L. M. (1998).
Effects of reinforcement rate and delay on the acquisition of lever pressing by rats.
Journal of the Experimental Analysis of Behavior,
69, 59-75.
The acquisition of lever pressing by naive rats, in the absence
of shaping, was studied as a function of different rates and
unsignaled delays of reinforcement. Groups of 3 rats were each
exposed to tandem schedules that differed in either the first or
the second component. First-component schedules were either
continuous reinforcement or random-interval 15, 30, 60, or 120 s;
second-component schedules were fixed-time 0, 1, 3, 6, 12, or 24
s. Rate of responding was low under continuous immediate
reinforcement and higher under random- interval 15 s. Random
interval 30-s and 60-s schedules produced lower rates that were
similar to each other. Random-interval 120 s controlled the
lowest rate in the immediate-reinforcement condition. Adding a
constant 12-s delay to each of the first-component schedule
parameters controlled lower response rates that did not vary
systematically with reinforcement rate. The continuous and
random-interval 60-s schedules of immediate reinforcement
controlled higher global and first-component response rates than
did the same schedules combined with longer delays, and
first-component rates shoed some graded effects of delay
duration. In addition, the same schedules controlled higher
second-component response rates in combination with a 1-s delay
than in combination with longer delays. These results were
related to those from previous studies on acquisition with
delayed reinforcement as well as to those from similar
reinforcement procedures used during steady-state responding.
Key words: response acquisition, reinforcement rate,
reinforcement delay, lever press, rats