Discriminative functions of schedule stimuli and memory: a combination of schedule and choice procedures.
Bright, brief stimuli during fixed-interval schedules sharpen both the wait curve and later time-based choices.
01Research in Context
What this study did
The team ran brief-stimulus fixed-interval schedules. After each interval a quick flash or tone marked the passage of time.
Then they gave the birds a choice test. Two keys lit up; the bird had to pick the side that matched the just-finished interval length.
What they found
When the brief stimulus was bright and easy to notice, the birds showed the classic FI scallop and aced the memory test.
Longer intervals flattened both the scallop and the choice accuracy. Salient stimuli protected both skills.
How this fits with other research
Sturmey (1994) had already shown that a brief cue alone can push response rates up or down across tandem VR-VI parts. A et al. add a memory probe and prove the same cue also sharpens temporal recall.
Périkel et al. (1974) saw mixed effects: brief stimuli sometimes helped, sometimes hurt, depending on the schedule. The 1978 study cuts through the noise by pairing the cue with an explicit choice test, showing the benefit is real when the stimulus is salient.
Dougan (1987) found that the prior interval length quietly bends current FI responding. A et al. echo this: longer FIs now weaken both the scallop and later discrimination, so stimulus salience becomes even more critical.
Why it matters
If you use timer boards, progress bars, or colored lights to mark intervals, make them bold and consistent. A sharper cue locks in the wait pattern and helps the learner remember how long they just waited. Next time you stretch the FI, bump up the stimulus intensity to keep both the pause and the memory intact.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Make your interval marker 20% louder or brighter and track if the learner’s pause gets cleaner.
02At a glance
03Original abstract
Pigeons responded under a combination brief-stimulus schedule and choice procedure. Normally, a fixed-interval schedule was in effect, where completion randomly produced either a brief stimulus or food. Intermittently, this schedule was interrupted by a choice arrangement. Two choice keys were lit, either a short or a long time since a prior event (food or stimulus). One choice response produced food if the time had been short, and the alternate response produced food if the time had been long. Across conditions, the duration of the fixed-interval schedule was varied, the stimuli that comprised the brief-stimulus operation were changed, and the stimuli were presented as paired and nonpaired with food. The focus of the study was the control of both schedule performance and choice responding across conditions. The results showed that choice accuracy was correlated with the degree of fixed-interval curvature, the response pattern of a pause followed by a gradually accelerated rate. As fixed-interval schedule duration was increased, both the degree of fixed-interval curvature and choice accuracy decreased. The particular brief stimulus used affected schedule and choice performance, with a more salient stimulus producing a greater degree of curvature and higher accuracy. Pairing and nonpairing operations produced striking differences in performance with the less salient brief stimulus, but not with the more salient stimulus. The results suggest that brief-stimulus schedule performance may be conceptualized in the context of memory research.
Journal of the experimental analysis of behavior, 1978 · doi:10.1901/jeab.1978.29-167