LeSage, M. G., Byrne, T., & Poling, A. (1996).
Effects of d-amphetamine on response acquisition with immediate and delayed reinforcement.
Journal of the Experimental Analysis of Behavior,
66, 349-367.
The present study examined in 8-hour sessions the effects of
d-amphetamine (1.0, 5.6, and 10 mg/kg) on the acquisition
of lever-press responding in rats that were exposed to procedures
in which water delivery was delayed by 0, 8, or 16 seconds
relative to the response that produced it. Both nonresetting- and
resetting-delay conditions were studied. Although neither shaping
nor autoshaping occurred, substantial levels of operative-lever
responding developed under all conditions in which responses
produced water. The lowes t dose (1.0 mg/kg) of
d-amphetamine either had no effect on or increased
operative-lever pressing, whereas higher doses typically produced
an initial reduction in lever pressing. Nonetheless, overall
rates of operative-lever pressing at these doses were as high as,
or higher than, those observed with vehicle. Thus, response
acquisition was observed under all reinforcement procedures at
all drug doses. In the absence of the drug, most responding
occurred on the operative lever when reinforcement was immediate.
Such differential responding also developed under both
nonresetting- and resetting-delay procedures when the delay was 8
seconds, but not when it was 16 seconds. d-Amphetamine did
not affect the development of differential responding under any
procedure. Thus, consistent with d-amphetamine's effects
under repeated acquisition procedures, the drug had no
detrimental effect on learning until doses that produced general
behavioral disruption were administered.
Key words: delayed reinforcement, d-amphetamine, acquisition,
tandem schedules, water, lever press, rats