Modifying drug-reinforced behavior by altering the economic conditions of the drug and a nondrug reinforcer.
Give clients a strong, easy alternative reward and they will often choose it over drugs or problem behavior.
01Research in Context
What this study did
Researchers gave rats two levers. One delivered phencyclidine (PCP). The other gave sweet saccharin water.
They changed the price of PCP by raising the number of lever presses needed. They also lowered the drug strength.
Then they watched how much PCP the rats took when saccharin was or was not an option.
What they found
When PCP cost more presses, rats took less drug. Weak PCP also cut intake.
Adding saccharin water slashed drug use by 20 to 90 percent. The sweet drink acted like a cheap, strong reinforcer that out-competed the drug.
How this fits with other research
Toegel et al. (2025) later showed the same idea works in people. Money rewards helped adults with HIV stay on meds and keep virus levels low.
Kazdin (1977) set the math. His matching law predicted how rats split time between two rewards. The 1991 study used that math to explain why saccharin beat PCP.
Kuroda et al. (2018) added that the link between response and reward—not just timing—drives choice. This supports the price view used here.
Why it matters
You can cut drug use by making healthy rewards easier and cheaper than the drug. In your clinic, pair hard tasks with strong, quick non-drug rewards. Watch the client shift choice toward the healthier option.
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02At a glance
03Original abstract
Six rhesus monkeys were trained to self-administer orally delivered phencyclidine (0.25 mg/mL) and saccharin (0.03% wt/vol) under concurrent fixed-ratio 16 schedules. In Condition 1 the fixed-ratio requirement for phencyclidine was changed from 16 to 4, 8, 16, 32, 64, 128 and 16 while the fixed-ratio requirement for saccharin deliveries remained constant at 16. In Condition 2 the fixed-ratio value for saccharin was systematically altered while the fixed-ratio requirement for phencyclidine remained at 16, and in Condition 3 the fixed-ratio requirements for both phencyclidine and saccharin were altered simultaneously. Water was then substituted for saccharin, and the series of fixed-ratio manipulations was replicated. The phencyclidine concentration was reduced to 0.125 mg/mL and Conditions 1 and 3 were repeated. When the fixed-ratio requirement for phencyclidine was increased and the fixed-ratio requirement for saccharin or water remained fixed at 16, phencyclidine deliveries decreased when saccharin (vs. water) was concurrently available. The magnitude of the decrease ranged from 20% to 90% (of the concurrent water condition) as the fixed-ratio requirement for phencyclidine increased from 4 to 128. When the fixed-ratio requirement for phencyclidine remained at 16 and the fixed-ratio requirements for concurrent saccharin or water varied between 4 and 128, phencyclidine deliveries decreased by 30% to 40% due to the concurrent availability of saccharin (vs. water). This decrease occurred only at the three lowest fixed-ratio values when saccharin intake was relatively high. When the fixed-ratio requirements for both phencyclidine and concurrent saccharin or water were varied simultaneously, phencyclidine deliveries were reduced from 20% to 45% when saccharin (vs. water) was concurrently present. There was little effect of reducing the phencyclidine concentration when the data were analyzed in terms of unit price (responses per milligram). Thus, changes in the fixed-ratio requirement or drug concentration were functionally similar, and unit price of phencyclidine was the variable that was influenced by the presence of concurrent saccharin. These data indicate that drug-reinforced behavior is substantially reduced when the environment is enriched with an alternative nondrug reinforcer. The economic context in which these substances are presented is an important determinant of drug-reinforced behavior.
Journal of the experimental analysis of behavior, 1991 · doi:10.1901/jeab.1991.56-361