Food and cocaine self-administration by baboons: effects of alternatives.
When food costs more effort, cocaine becomes the better deal, showing how reinforcer value changes with price.
01Research in Context
What this study did
Scientists let baboons choose between food pellets and cocaine.
Each choice cost a set number of lever presses.
The team raised the pellet price and watched what happened.
They also compared cocaine to a sweet drink that had no drug.
What they found
When pellets cost more, the animals ate fewer pellets.
If cocaine was also present, pellet eating dropped even more.
The baboons took more cocaine than the sweet drink.
Cocaine acted like a stronger replacement for food.
How this fits with other research
Michael (1974) showed that a cue’s value flips when the schedule changes.
That early work helps explain why higher pellet cost makes cocaine more attractive.
Russell et al. (2018) later saw a similar trade-off in children choosing tokens or snacks.
Both studies show that when one reinforcer gets pricey, another can step in.
Why it matters
You can spot the same economic rule in the clinic.
If your client has to work harder for a highly preferred edible, they may switch to a different reward.
Watch for shifts in choice when you raise task effort.
Keep backup reinforcers ready so the child does not drop out of the program.
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02At a glance
03Original abstract
The effects of the availability of an alternative reinforcer on responding maintained by food pellets or drug solutions were examined in 8 adult male baboons (Papio hamadrayas anubis). During daily 23-hr experimental sessions, baboons had access to both food pellets and fluid under a two-choice procedure, in which the response requirement, under a fixed-ratio schedule, differed for the two commodities. There were no restrictions on access to water, which was continuously available from a spout at the rear of each cage. In Experiment 1, the fixed-ratio requirement, or cost, for fluid delivery remained constant while the fixed-ratio requirement for pellets was changed every 2 or 3 days when (a) no fluid, (b) a dilute dextrose vehicle, (c) 0.008 mg/kg per delivery cocaine, (d) 0.016 mg/kg per delivery cocaine, or (e) 0.032 mg/kg per delivery cocaine was available concurrently. In Experiment 1, progressively increasing the response requirement for pellets decreased pellet intake, but for 4 baboons pellet intake at maximum pellet cost was lower when cocaine, compared to the vehicle, was available. Increasing the response requirement for pellets had variable effects on vehicle intake. However, increasing the response requirement for pellets increased intake of at least one dose of cocaine to a greater extent than vehicle in all 8 baboons. Thus, cocaine could be considered a more effective economic substitute than vehicle for pellets. Experiment 2 systematically varied the order in which the response requirements for a pellet delivery were presented and added a control condition in which cocaine doses, yoked to the amount self-administered, were given three times during the session by the experimenter. Again, pellet intake at maximal pellet cost was lower when cocaine, compared to the vehicle, was available. In contrast, experimenter-given cocaine doses did not alter responding maintained by pellets. Thus, the effects of self-administered cocaine on responding maintained by food pellets differed from the effects of experimenter-given cocaine on responding maintained by food pellets.
Journal of the experimental analysis of behavior, 1999 · doi:10.1901/jeab.1999.72-215