Fixed-interval schedule of cocaine reinforcement: effect of dose and infusion duration.
Cocaine dose and infusion speed trade off to control response rate on fixed-interval schedules, mirroring how any reinforcer’s size and delivery speed shape behavior.
01Research in Context
What this study did
Scientists gave rats cocaine through a tiny tube in their vein.
The rats pressed a lever on a 9-minute fixed-interval schedule.
Each press delivered a cocaine dose that varied in amount and speed.
What they found
Higher cocaine doses made the rats press more often.
Shorter, faster infusions worked like bigger doses.
The timing of the drug, not just the amount, shaped the behavior.
How this fits with other research
Staddon (1970) first showed that longer food pellets stretch the pause after reinforcement.
Gabriels et al. (2001) later ran the same 9-minute schedule for weeks and found tolerance; response rates fell even though cocaine kept coming.
Pilowsky et al. (1998) swapped cocaine for wheel-running and saw the same rule: longer reinforcer access cuts later pressing.
Together the four papers show the dose-duration trade-off works for food, drugs, or play.
Why it matters
You can apply the same rule to edible reinforcers. Short, high-value bites often do the job of larger ones. Watch for tolerance if you keep the same rich reward day after day; stretch the interval or swap the item before the behavior weakens.
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02At a glance
03Original abstract
Rhesus monkeys were trained on a fixed-interval 9-min limited-hold 3-min schedule of intravenous cocaine reinforcement. A 15-min timeout followed each reinforcement or limited-hold expiration. An identical schedule of food reinforcement was interspersed in the session to assess rate-modifying effects of the drug infusions not specific to drug reinforcement. In one experiment, response rate for cocaine reinforcement was shown to be a positive function of reinforcement magnitude for a dose range from 0 to 800 ug/kg/inj. At these doses, there was little effect on food reinforced responding except at the highest dose, where responding decreased. Results of the second experiment indicated that increasing the duration of the cocaine infusion produced a change in response rate similar to decreasing unit dose. The response rate change for a given increase in infustion duration was less at a unit dose of 400 ug/kg than at 200 ug/kg.
Journal of the experimental analysis of behavior, 1973 · doi:10.1901/jeab.1973.20-119