Discriminability between alternatives in a switching-key concurrent schedule.
A 10-second pause between schedule and matching phases flattens preference yet keeps stimulus control sharp in pigeons.
01Research in Context
What this study did
Researchers worked with pigeons on a two-part task. First, birds pecked on a switching-key concurrent schedule. Next, they entered a symbolic matching-to-sample phase.
The team added a 10-second delay between the two parts. They wanted to see how the pause changed choice and stimulus control.
What they found
The delay pushed choice toward indifference. Birds stopped strongly favoring the richer key.
Even though preference weakened, the birds could still tell the cues apart. Discriminability stayed intact.
How this fits with other research
Neuringer et al. (1968) showed that a changeover delay reduces switching. Alsop et al. (1992) used the same idea, but placed the delay between phases instead of within the schedule.
Leigland (1987) found that richer concurrent schedules flatten stimulus-control gradients. Alsop et al. (1992) agree that schedule changes affect control, yet they show discriminability can survive when preference drops.
Krägeloh et al. (2003) later doubled choice sensitivity by signaling reinforcer ratios. Their work extends the 1992 finding: delays reduce preference, but added signals can bring sensitivity back up.
Why it matters
When you insert a gap between task parts, expect looser preference but intact discrimination. This matters for conditional-discrimination drills with clients who need brief breaks. You can give a 10-second pause without re-teaching the cues. Watch for flatter choice patterns and be ready to add signals or other supports if you need sharper responding again.
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02At a glance
03Original abstract
Six pigeons were trained to discriminate between two intensities of white light in a symbolic matching-to-sample procedure. These stimuli were then used to signal which schedule was available on the main key in a switching-key concurrent schedule. The concurrent schedules led to a symbolic matching-to-sample phase in which the subject identified the concurrent schedule to which it last responded before a reinforcer could be obtained. The concurrent schedules were varied across conditions. Discriminability, measured during the symbolic matching-to-sample performance, was high throughout and did not differ across the two procedures. Performance in the concurrent schedules was like that typically obtained using these schedules. Delays were then arranged between completion of the concurrent schedules and presentations of the symbolic matching-to-sample phase. A series of conditions with an intervening delay of 10 s showed that both concurrent-schedule performance and symbolic matching-to-sample performance were affected by the delay in a similar way; that is, choice responding was closer to indifference.
Journal of the experimental analysis of behavior, 1992 · doi:10.1901/jeab.1992.57-51