Second-order schedules: comparison of different procedures for scheduling paired and nonpaired brief stimuli.
Under second-order schedules, stimulus-food pairing doesn’t affect the FI response pattern—schedule structure alone maintains curvature.
01Research in Context
What this study did
Researchers put pigeons on a second-order FI-VI schedule. A brief light flashed at the end of each FI component.
Some birds got the light paired with food. Others got the light alone. The team wanted to know if pairing changed the FI scallop pattern.
What they found
The birds scalloped the same way no matter what. Paired or unpaired, the light did not shift the curved response pattern.
Schedule structure, not the food pairing, drove the within-component timing.
How this fits with other research
Squires et al. (1975) later showed pigeons could not tell where they were inside the same schedule unless each part had its own external cue. Together the papers say: pairing is irrelevant, but clear markers help the bird know its place.
Neuringer (1973) used pure autoshaping and found that shorter stimuli made pecking start faster. That study cared about pairing, yet the 1972 paper shows pairing does not matter once the schedule is running.
Mulvaney et al. (1974) saw weak automaintenance in monkeys when the response-reinforcer link vanished. The 1972 data say the link is already weak inside second-order schedules; structure rules.
Why it matters
You can stop worrying about pairing every brief stimulus with food. Focus on the schedule layout and on adding clear cues if you need the learner to discriminate components. Next time you build a chained or second-order program, save effort: use neutral brief stimuli and spend your energy on salient component markers instead.
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02At a glance
03Original abstract
Pigeons performed on a second-order schedule in which fixed-interval components were maintained under a variable-interval schedule. Completion of each fixed-interval component resulted in a brief-stimulus presentation and/or food. The relation of the brief stimulus and food was varied across conditions. Under some conditions, the brief stimulus was never paired with food. Under other conditions, the brief stimulus was paired with food; three different pairing procedures were used: (a) a response produced the simultaneous onset of the stimulus and food; (b) a response produced the stimulus before food with the stimulus remaining on during food presentation; (c) a response produced the stimulus and the offset of the stimulus was simultaneous with the onset of the food cycle. The various pairing and nonpairing operations all produced similar effects on performance. Under all conditions, response rates were positively accelerated within fixed-interval components. Total response rates and Index of Curvature measures were similar across conditions. In one condition, a blackout was paired with food; with this different stimulus in effect, less curvature resulted. The results suggest that pairing of a stimulus is not a necessary condition for within-component patterning under some second-order schedules.
Journal of the experimental analysis of behavior, 1972 · doi:10.1901/jeab.1972.18-403