Free-operant forgetting: Delayed stimulus control of multiple-schedule performance.

The team worked with pigeons in a lab.

They used a multiple schedule with colored and white lights.

The birds pecked for food that came after a delay.

The goal was to see how well the colors still guided choices later.

Colored lights kept tighter control than white lights.

The birds’ response ratios matched the reinforcement ratios better when the cue was colored.

This shows delayed stimulus control can be measured by comparing sensitivity under strong versus weak cues.

CHUNG (1965) first showed pigeons can learn the job when the cue and food are split in time. McGee et al. (1983) now give us a number for how much control remains.

Harrison et al. (1975) used a similar setup and found inhibition still forms after errorless training. Together the two papers say: delayed cues still work, both for turning behavior on and off.

Squires et al. (1975) saw that birds could not tell schedule parts apart without clear markers. G et al. add that once you add color markers, control grows stronger, even after a gap.

You now have a simple way to test if a client still “hears” the cue after a delay. Pick a bright color for the SD and a dull white for the SΔ. Compare response rates. If the ratio gap is small, the learner may need the cue closer in time or extra salience. Try moving the cue earlier or making it bolder, then measure again.