Alternative reinforcement effects on fixed-interval performance.

Researchers placed pigeons on a fixed-interval food schedule. Every 60 seconds the first peck after the interval produced grain. On top of that they added a DRO schedule. If the bird stopped pecking for a set time, it earned extra grain. They varied how long the pause had to be and how often the DRO paid off.

The team wanted to see if this second reinforcer would change the birds’ timing and rate of pecking.

Longer required pauses and richer DRO pay made the birds wait more before they started pecking. The usual scallop-shaped response pattern flattened out. Even though the main food stayed on the same 60-second clock, the extra ‘don’t peck’ money reshaped the whole performance.

Zimmerman (1969) saw the same kind of override in rats. A conditioned reinforcer schedule pulled response rates away from the primary FI schedule, just like the DRO did here. The idea that a second contingency can boss around the first one is not new.

Davison et al. (1984) later showed that where you place the response rule inside any interval also moves pause time. Bacon-Prue et al. (1980) and Davison et al. (1984) together tell us that both ‘when you must not respond’ and ‘when you must respond’ are active levers.

Lawer et al. (2009) took the DRO trick into a classroom. A teenager with brain injury got faster at math when DRO plus tokens paid him for waiting less than three seconds. Same principle, new species and a socially important goal.

If you want to stretch wait time or smooth out burst responding, stack a DRO on top of your main schedule. Start with short pauses and dense pay, then thin it out. You can use this to reduce stereotypy, increase latency before problem behavior, or shape calmer work patterns in clients who rush or respond too fast.