Fixed-time schedule effects in combination with response-dependent schedules.

Three adults with developmental disabilities worked on simple vocational tasks.

Each person faced three setups: fixed-interval (FI) alone, fixed-time (FT) alone, and both schedules together.

The team measured how many tasks each adult completed under each condition.

FT alone cut work output for two of the three adults.

When FI and FT ran together, two adults kept working at steady rates.

One adult worked less even with the combined schedule, showing individual differences matter.

Fay (1979) showed rats pause after food in fixed-interval setups. The new study adds FT deliveries and tests people, not rats.

Catania et al. (1982) found pigeons act oddly when extra stimuli appear. The current work shows extra food deliveries (FT) can also change behavior, linking superstition to schedule type.

Szempruch et al. (1993) saw pigeons adjust wait times to interval changes. The adults here did the same: when FT food arrived regardless of work, some stopped waiting and stopped working.

If you use noncontingent reinforcement, pair it with response-based rewards. FT alone can kill the very behavior you want to keep. Test each learner—some need stronger response-dependent schedules than others.