Effects of ethanol on multiple fixed-interval fixed-ratio schedule performances: dynamic interactions at different fixed-ratio values.
Ethanol’s impact on behavior flips with baseline response rate and schedule type, so past data can’t predict future effects without fresh probes.
01Research in Context
What this study did
Bernal et al. (1980) gave lab rats ethanol while they worked on a two-part schedule.
One part paid on fixed-interval (FI) time. The other paid on fixed-ratio (FR) count.
The team changed the FR size across days and watched how the drug moved responding.
What they found
Ethanol did not push every behavior the same way.
When the ratio was big, FI responding rose the most.
When baseline FR rates were low, the same dose lifted FR rates instead.
Repeating the dose made the curve shift, so past runs changed the next outcome.
How this fits with other research
Falk (1966), Nelson et al. (1978), and Blackman (1970) all showed that longer FI schedules make rats drink more water right after each pellet. Bernal et al. (1980) used those same FI lengths, so the "extra" FI responding after ethanol may ride on top of that baseline adjunctive drinking.
Cherek et al. (1970) proved that bigger FR values also spike schedule-induced aggression. Bernal et al. (1980) now show that a bigger FR can also magnify ethanol’s lift of FI behavior, pointing to a common pathway: higher ratio requirements heighten schedule-induced side effects.
Hymowitz et al. (1974) split FI performance into tiny segments to reveal that d-amphetamine changes response probability, not just overall rate. Bernal et al. (1980) echo this idea by showing ethanol effects flip with baseline rate, urging us to look past simple averages when drugs or any variable is in play.
Why it matters
For BCBAs, the lesson is that a client’s current response rate sets how any intervention (or medication) will look.
High-rate behavior may dip, low-rate behavior may climb, and past exposure can move the curve.
Track each schedule component separately and re-check baselines often; yesterday’s "no effect" can become tomorrow’s big change.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Plot each schedule component’s rate before and after any change (meds, new ratio, etc.) to spot if the shift matches the baseline trend seen in this rat data.
02At a glance
03Original abstract
Key pecking by three pigeons was maintained under a multiple fixed-interval fixed-ratio schedule of food presentation. The fixed-interval value remained at 3 minutes, while the fixed-ratio size was increased systematically in 30-response increments from 30 to either 120 (two pigeons) or 150 (one pigeon). At least two lower fixed-ratio values were also redetermined. The effects of ethanol (5 to 2.5 g/kg) were assessed at each of the different schedule parameters. Both overall and running response rates under the fixed-ratio schedule decreased with increases in the size of the fixed-ratio schedule; pause duration under the fixed-ratio schedule was directly related to increases in fixed-ratio size. Overall and running rates of responding under the fixed-interval schedule changed little with increases in the size of the fixed-ratio schedule. Despite the relative invariance of fixed-interval responding across the different fixed-ratio values, the effects of ethanol on responding under the fixed-interval schedule differed depending on the size of the fixed-ratio schedule. Greater increases occurred in both overall and in lower local rates of responding under the fixed-interval schedule when the fixed-ratio value was 120 or 150. The effects of ethanol on responding under the fixed-ratio schedule also depended on the size of the fixed ratio. Increases in responding under the fixed-ratio schedule were typically greater at the higher fixed-ratio values where response rates were lower. When the effects of ethanol were redetermined at the lower fixed-ratio parameter values, rates and patterns of responding were comparable to those obtained initially. However, the dose-effect curves for responding under both fixed-ratio and fixed-interval schedules were shifted up and to the right of those determined during the ascending series. The effects of ethanol can depend on rate or responding, behavioral history, and the context in which behavior occurs.
Journal of the experimental analysis of behavior, 1980 · doi:10.1901/jeab.1980.34-185