Concurrent access to two concentrations of orally delivered phencyclidine: effects of feeding conditions.
Food satiation versus hunger changed the timing, not the total amount, of concurrent oral PCP self-administration in monkeys.
01Research in Context
What this study did
Monkeys could sip two strengths of PCP at any time. One bottle held weak drug. The other held strong drug.
The team first fed the monkeys until full. Later they let the monkeys work only for food so they were hungry. They compared when and how much PCP was drunk in each feeding state.
What they found
Full or hungry, the animals drank about the same total drug each day. Hunger did not raise intake. Satiation did not lower it.
The timing changed. Hungry monkeys took most drug early in the session. Full monkeys spread drinks across the whole period.
How this fits with other research
Foltin (1997) saw a different picture. When baboons had to press many times for food pellets, they switched and took more amphetamine. That study shows food restriction can boost drug use if the drug is the easier option.
Pigott (1987) kept both drug bottles easy to reach. Because cost stayed low, the monkeys saw no reason to shift. The two papers agree: price, not hunger, decides the final amount.
J et al. (1991998) mapped cocaine drinking the same way. They showed intake follows unit price. The 1987 data add a new layer: even when price is flat, feeding state can still shuffle the daily rhythm.
Why it matters
For BCBAs the lesson is about schedule design, not drugs. If you want to reduce a reinforcer, raise its response cost first. Simply removing food or giving free snacks may only move the behavior around in time. Check when the responses happen, not just how many.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Plot the minute-by-minute pattern of a problem behavior under both pre-feed and food-deprivation conditions before you adjust the reinforcement plan.
02At a glance
03Original abstract
Two experiments addressed the effects of food satiation and deprivation on oral self-administration of two concurrently available phencyclidine concentrations. In the first experiment, 8 rhesus monkeys self-administered either of two concentrations of phencyclidine ("PCP, angel dust") and water under concurrent fixed-ratio 16 schedules. One concentration was always held constant (0.25 mg/mL) while a series of other phencyclidine concentrations, ranging from 0 (water) to 1.0 mg/mL, was presented in a nonsystematic order. Initially the monkeys were tested while food satiated, and the procedure was then repeated during food deprivation. The monkeys usually selected the higher concentration within the first few minutes of the session, indicating that taste and/or other immediate postingestional effects were important factors. Contrary to a number of previous reports, there were no consistent differences across subjects in the mean number of liquid deliveries or mean drug intake (mg/kg) during food satiation and deprivation. However, for all monkeys the within-session time course of responding during food satiation consistently differed from that during deprivation. A second experiment assessed whether the failure to find consistent differences in drug intake during food satiation and deprivation had been due to the history of concurrent access to different phencyclidine concentrations or to the extended experience with phencyclidine under food-satiation conditions. Six additional monkeys (Group 2) were exposed to the phencyclidine self-administration procedure (during food satiation and deprivation) for the same length of time as the monkeys in Experiment 1 (Group 1), except they received only concurrent access to phencyclidine (0.25 mg/mL) and water. Both groups then received concurrent access to phencyclidine and water during five repeated cycles of food deprivation and satiation. There were also marked individual differences in Group 2: During food satiation, 2 of the monkeys' responding increased, 1 showed no change, and 3 decreased. Examination of a number of historical variables indicated that the greater the percentage of total sessions spent during food satiation with phencyclidine available (before these experiments began), the greater the amounts of phencyclidine consumed during food satiation and the smaller the differences in phencyclidine intake when the two feeding conditions were compared.
Journal of the experimental analysis of behavior, 1987 · doi:10.1901/jeab.1987.47-347