Effects of D-amphetamine on response acquisition with immediate and delayed reinforcement.
Moderate d-amphetamine does not stop new lever-press learning in rats even with 8-s delayed reinforcement.
01Research in Context
What this study did
LeSage et al. (1996) asked if d-amphetamine stops rats from learning a new lever press when food comes late. They gave three drug doses: 1, 5.6, and 10 mg/kg. Each rat had to press a bar even though the food arrived 8 s after the press.
What they found
All rats learned the lever press under every delay and every dose. Only the highest dose wrecked learning. Moderate d-amphetamine did not block acquisition with delayed reinforcement.
How this fits with other research
Reiss et al. (1993) already showed rats can learn under 8-s delays without any drug. LeSage et al. (1996) adds that the same learning still happens under moderate amphetamine.
Billings et al. (1985) found that strong cues protect performance from amphetamine disruption. The new study agrees: learning survives unless the dose is so high it wipes out all responding.
Lucki et al. (1983) says amphetamine raises low response rates and cuts high ones. Early acquisition has naturally low rates, so the drug slightly helps at first, matching the rate-dependency rule.
Why it matters
If you work with clients on stimulant meds, this rat data says moderate doses are unlikely to stop new skill learning even when reinforcement is delayed. You can keep teaching even when the doctor raises the dose slowly. Watch only for very high doses that make the child unable to sit or attend.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Keep running your acquisition program after the doctor increases stimulant dose; only pause if you see clear motor disruption.
02At a glance
03Original abstract
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 lowest 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.
Journal of the experimental analysis of behavior, 1996 · doi:10.1901/jeab.1996.66-349