An experimental analysis of the effects of d-amphetamine and cocaine on the acquisition and performance of response chains in monkeys.
New behavior falls apart under stimulant drugs, but old skills stay fairly safe.
01Research in Context
What this study did
Researchers gave monkeys d-amphetamine or cocaine. They tested how well the monkeys learned new button-pressing chains versus how well they performed old ones.
Each monkey worked on two types of tasks. One task was brand-new each session. The other task was the same every day. The team compared errors and speed.
What they found
Both drugs badly hurt learning. Monkeys made far more errors when they had to master a new chain.
The same drugs only slightly hurt old, well-practiced chains. Once a skill was solid, the drugs did much less damage.
How this fits with other research
Martens et al. (1989) later saw the same pattern with diazepam in humans. New learning suffered more than old performance, showing the effect holds across drugs and species.
Joyce et al. (1988) used a rat maze and scopolamine. Again, within-session learning dropped while practiced choices stayed fairly accurate. The repeated-acquisition design keeps telling the same story.
HEFFERLINE et al. (1963) mapped stimulant fingerprints in rats. Their early work helps explain why d-amphetamine, not just any drug, gives this acquisition hit.
Why it matters
If a client starts a new medication, expect bigger trouble when you teach brand-new skills. Keep highly familiar routines running smoothly for maintenance, but slow down the pace of new targets until the body adjusts. Track errors session-by-session; any spike may be the drug, not your program.
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02At a glance
03Original abstract
In one component of a multiple schedule of food presentation, monkeys acquired a different four-response chain each session by responding sequentially on three keys in the presence of four geometric forms (learning). In the other component, the four-response chain was the same each session (performance). Both d-amphetamine and cocaine, at the higher doses, disrupted the behavior in the learning component; the overall response rate decreased, the overall accuracy was impaired (i.e., percent errors increased), and there was less within-session error reduction. The performance component was generally less sensitive than the learning component to the disruptive effects of both drugs on rate and accuracy. After pre-feeding or during an extended session, the response rate decreased in both components, but accuracy was generally unaffected. When the four discriminative stimuli in both components were removed, the behavior was disrupted to a greater extent in the performance component. The disruptive effects of both drugs on behavior in the learning component were attenuated when the drugs were administered during the session after the response chain had been acquired. It was concluded that the greater sensitivity of the learning component to disruptive drug effects is related to the relatively weak stimulus control and/or the lower rate of reinforcement associated with that component.
Journal of the experimental analysis of behavior, 1979 · doi:10.1901/jeab.1979.32-433