Effects of cocaine and alcohol, alone and in combination, on human learning and performance.
Cocaine can shield new learning from alcohol’s damage in lab tasks, showing that consequences and task type decide a drug’s real-world impact.
01Research in Context
What this study did
Adults without disabilities took repeated learning tests in a lab. Each person swallowed capsules that gave alcohol, cocaine, both, or nothing.
The task was a new button sequence every round. Scientists counted right moves and speed.
What they found
Alcohol alone hurt accuracy and slowed responding. Cocaine alone made accuracy better with no speed change.
When the two drugs were mixed, alcohol’s damage shrank. Cocaine partly blocked the alcohol slump.
How this fits with other research
Goldman et al. (1979) saw the opposite in pigeons: cocaine raised errors. The bird task punished mistakes, while the human task only praised corrects. Different consequences flip cocaine’s effect.
Locurto et al. (1980) showed stimulus fading cuts stimulant errors. Higgins et al. (1992) show another buffer: cocaine itself can soften alcohol’s hit. Both papers give ways to protect learning from drug disruption.
Cohen et al. (1990) found alcohol only hurt repeated, not varied, rat lever presses. The human study widens this: alcohol hurts new sequence learning, a close cousin to repetition.
Why it matters
You may not dose clients, but the data remind us that consequences control whether a substance helps or harms performance. If a learner is slower after a new med, check the task first. Add prompts or richer praise; these act like the “cocaine buffer” and can restore accuracy without any drug.
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02At a glance
03Original abstract
The acute effects of cocaine hydrochloride (4 to 96 mg/70 kg) and alcohol (0 to 1.0 g/kg), administered alone and in combination, were assessed in two experiments with human volunteers responding under a multiple schedule of repeated acquisition and performance of response chains. Subjects were intermittent users of cocaine and regular drinkers who were not cocaine or alcohol dependent. Alcohol was mixed with orange juice and ingested in six drinks within 30 min; cocaine was administered intranasally 45 min after completion of drinking. In each component of the multiple schedule, subjects completed response sequences using three keys of a numeric keypad. In the acquisition component, a new sequence was learned each session. In the performance component, the response sequence always remained the same. Results were consistent in both experiments, despite variations in the order in which the drugs were tested alone and in combination. Alcohol administered alone increased overall percentage of errors and decreased rates of responding in the acquisition component, whereas responding in the performance component generally was unaffected. Cocaine administered alone decreased rates of responding but did not affect accuracy of responding in the acquisition component, and enhanced accuracy of responding without affecting rates of responding in the performance component. The combined doses of cocaine and alcohol attenuated the effects observed with alcohol and cocaine alone. These results suggest that, under the conditions investigated in this study, (a) alcohol produces greater behavioral disruption than cocaine or cocaine-alcohol combinations, (b) cocaine and alcohol each attenuate effects of the other, and (c) such attenuation is most pronounced for cocaine attenuating the disruptive effects of alcohol.
Journal of the experimental analysis of behavior, 1992 · doi:10.1901/jeab.1992.58-87