An inverse relationship between baseline fixed-interval response rate and the effects of a tandem response requirement.
Baseline response rate predicts who will speed up when you add a small ratio to an interval schedule.
01Research in Context
What this study did
Honig et al. (1988) asked a simple question. If you tack a small ratio requirement onto a fixed-interval schedule, who speeds up and who stays the same?
They started with plain FI schedules. Then they added a tandem FR 9. That means nine responses had to occur before the usual FI timer could finish.
What they found
Animals that responded slowly on the baseline FI sped up when the FR 9 was added. Animals that already responded quickly stayed at the same rate.
The result looked like an inverse rule: low rate goes up, high rate stays flat.
How this fits with other research
Abrahamsen et al. (1990) ran a near-copy of the study and saw the same up-and-down pattern. Short FI / small FR boosted rates; long FI / large FR cut them. The inverse rule held across two labs.
Rapport et al. (1982) extended the rule to humans. College students with low FI rates optimized their pay when an FR was added, while fast responders barely changed. Same pattern, new species.
Ley (2001) seems to disagree. After 80–100 FI sessions, animals' old high- or low-rate histories no longer mattered. But R studied past history, not a fresh tandem requirement. Once the FR is actually added, baseline rate still wins.
Why it matters
When you design a chained or tandem schedule, check the client's current rate first. A child who barely responds during a 2-min interval may speed up if you slip in a small ratio. A child who already taps rapidly will probably ignore the extra work. Use the inverse rule to predict who will accelerate and who will stay flat.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Count baseline responses during your current FI. If the rate is low, test adding a small FR 5-10 before the interval ends and watch for acceleration.
02At a glance
03Original abstract
Previous experiments examining the effects of adding a tandem fixed-ratio response requirement on fixed-interval schedule performance have reported inconsistent results. One variable that may account for such inconsistencies is the baseline response rate in the fixed-interval condition. This possibility was investigated in the present study. Rats were given histories with either interresponse times greater than 11 s or fixed-ratio 40 schedules of reinforcement, which engendered either relatively low or high rates of responding, respectively, in the subsequent fixed-interval condition. A tandem ratio response requirement (fixed-ratio 9) was then introduced. The effects of adding this tandem response requirement were inversely related to the baseline fixed-interval response rates; low rates of responding in the fixed-interval condition were markedly increased, whereas high rates of responding were relatively unaffected. This inverse relationship appears to be similar to the rate-dependent relations observed in behavioral pharmacology. These results may provide an explanation for the inconsistent findings reported in previous studies on tandem fixed-interval fixed-ratio schedules and suggest that principles of behavioral pharmacology research may be applicable to the study of the effects of nonpharmacological variables on schedule-controlled behavior.
Journal of the experimental analysis of behavior, 1988 · doi:10.1901/jeab.1988.50-211