Second-order schedules: discrimination of components.
Learners can’t tell schedule parts apart unless each part carries its own clear signal.
01Research in Context
What this study did
Researchers used pigeons to test second-order schedules. Each schedule had many parts.
They asked: can birds tell which part they are in without extra cues?
Some schedules gave each part its own color light. Other schedules looked the same all the way through.
What they found
Birds pecked too early when every part looked the same.
When each part had its own color, birds waited until the right time.
The birds needed clear markers to know where they were in the chain.
How this fits with other research
Winett et al. (1972) showed that pairing the brief stimulus with food does not matter. The schedule shape stays the same. Squires et al. (1975) now show that the cue must still be different from the rest of the schedule. The two papers fit: structure drives the curve, but unique cues drive part-to-part knowing.
Campos et al. (2017) saw the same need with children. A multiple schedule alone did not bring manding under stimulus control. Adding salient cues helped, just like the pigeons needed colored lights.
Boyle et al. (2021) tested arbitrary versus natural cues during FCT thinning. Kids learned faster with arbitrary cues. This extends the lab finding to real therapy: pick clear, different signals if you want quick discrimination.
Why it matters
If you run chained or multiple schedules, give each piece its own look. A color change, a shape switch, or a short word can stop early responses. This works for token boards, timing lights, or FCT cards. Pick cues that stand out, then probe to be sure the learner notices the shift.
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02At a glance
03Original abstract
Pigeons were exposed to a series of second-order schedules in which the completion of a fixed number of fixed-interval components produced food. In Experiment 1, brief (2 sec) stimulus presentations occurred as each fixed-interval component was completed. During the brief-stimulus presentation terminating the last fixed-interval component, a response was required on a second key, the brief-stimulus key, to produce food. Responses on the brief-stimulus key before the last brief-stimulus presentation had no scheduled consequences, but served as a measure of the extent to which the final component was discriminated from preceding components. Whether there were one, two, four, or eight fixed-interval components, responses on the brief-stimulus key occurred during virtually every brief-stimulus presentation. In Experiment 2, an attempt was made to punish unnecessary responses on the brief-stimulus key, i.e., responses on the brief-stimulus key that occurred before the last component. None of the pigeons learned to withhold these responses, even though they produced a 15-sec timeout and loss of primary reinforcement. In Experiment 3, different key colors were associated with each component of a second-order schedule (a chain schedule). In contrast to Experiment 1, brief-stimulus key responses were confined to the last component. It was concluded that pigeons do not discriminate well between components of second-order schedules unless a unique exteroceptive cue is provided for each component. The relative discriminability of the components may account for the observed differences in initial-component response rates between comparable brief-stimulus, tandem, and chain schedules.
Journal of the experimental analysis of behavior, 1975 · doi:10.1901/jeab.1975.24-157