Fixed-interval limited-hold avoidance with and without signalled reinforcement.
A reinforcer’s signal keeps the FI scallop alive in avoidance; lose the signal, lose the pattern.
01Research in Context
What this study did
Alba et al. (1972) worked with lab rats on a fixed-interval avoidance task.
The animals could press a lever to stop a mild shock.
Half the rats heard a brief tone when the press worked; the other half got no sound.
The team watched whether the rats still showed the classic FI scallop—pause, then fast burst—without the tone.
What they found
Only the rats with the tone kept the neat FI pattern.
Without the signal, the pause-and-burst shape fell apart.
The result says the reinforcer’s own stimulus is as vital as the schedule itself.
How this fits with other research
CTGreenlee et al. (2024) later showed that the safety signal itself can strengthen human avoidance, proving the signal is not just a cue but a reinforcer.
Wearden et al. (1983) looked at pause length across FI schedules and found weak links between one pause and the next; their work deepens the 1972 finding by showing pause timing is fragile without added stimuli.
Timberlake et al. (1987) moved the same schedule to people in a game and still saw break-and-run patterns, confirming the basic FI shape holds across species when the right stimuli are present.
Why it matters
When you build an avoidance or DRL program, pair the success with a clear stimulus—a click, a word, a light.
The signal is part of the reinforcement, not extra polish.
Drop it and the tidy pattern you expect may melt away, wasting session time and learner effort.
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02At a glance
03Original abstract
Rats trained to lever press on a fixed-interval limited-hold avoidance schedule maintained a pattern of responding similar to that maintained by fixed-interval limited-hold schedules of positive reinforcement. But this positively accelerated pattern of behavior was maintained only when the occurrence of reinforcement was signalled by the presentation of a brief flash of light. This result suggests that the discriminative function of the reinforcer in avoidance is less pronounced than the discriminative function of the reinforcer in escape or positive reinforcement. It also suggests that the distinction between positive reinforcement and avoidance is not superfluous. Although the schedule of reinforcement is an important variable in determining the pattern of behavior, other variables, such as the nature (i.e., stimulus presentation, termination, or omission) of the reinforcer, are also potent determinants of behavior.
Journal of the experimental analysis of behavior, 1972 · doi:10.1901/jeab.1972.17-75