Ratio requirement and reinforcer effects in concurrent fixed-interval fixed-ratio schedules.

The team ran two schedules at once. One paid for fast responses. One paid for waiting.

They asked: does the size of the fast-response requirement change how hard animals work on the waiting schedule?

They tested two set-ups. In one, both schedules paid food. In the other, one paid food and one paid water.

When both reinforcers were the same (food/food), bigger ratio requirements slowed responding on the interval schedule.

When reinforcers differed (food/water), ratio size barely mattered. The type of reinforcer drove the behavior instead.

HEARST (1958) first showed that interval and ratio schedules feel different to the learner. The 1975 study adds that the reinforcer itself can flip those feelings.

Terrace (1969) found that ICS produced sharper stimulus control than food. Our target paper shows the same reinforcer-type effect inside concurrent schedules.

Whitehead et al. (1975) moved ratio rules into a classroom. They showed FR-3 to FR-5 boosts picture naming in kids with ID. The lab result here gives the reason: intermediate ratios balance effort and payoff.

If you run two contingencies at once, check what each one pays. A high-effort token board paired with free iPad time may fizzle if the reinforcers feel too different. Try matching the payoff types first, then tweak the response requirements. You might get smoother behavior without raising ratio size.