Conditioned suppression or facilitation as a function of the behavioral baseline.
The baseline reinforcement schedule decides whether a warning stimulus suppresses or facilitates responding.
01Research in Context
What this study did
Zeiler (1968) tested how a warning tone changes lever pressing when mild or strong shock might follow. One group of rats worked on a DRL schedule: press, wait, press. Another group worked on an FI schedule: press, wait for the buzz, press again. A tone sounded before each possible shock. The team varied shock intensity across days while recording response rates.
What they found
On DRL, low shock plus tone made rats press faster. High shock plus tone made them press slower. On FI, any shock level plus tone always slowed pressing. The same warning stimulus could either help or hurt responding, depending on the baseline schedule and shock strength.
How this fits with other research
HOLZ et al. (1963) saw only slower DRL pressing when shock arrived. Zeiler (1968) shows the full picture: weak shock can speed DRL up, strong shock still slows it down. The two papers fit like puzzle pieces.
McKearney (1970) later added VR and VI schedules. Ratio schedules dropped fast when shock increased, while interval schedules recovered faster when shock eased. Together, the studies show punishment hits each schedule differently.
Iversen et al. (1984) replaced the single tone with pairs of shocks. Short gaps between shocks slowed pressing; longer gaps sped it up. Their pattern matches Zeiler (1968): timing and intensity decide whether behavior drops or rises.
Why it matters
When you add a warning stimulus or punishment, first ask: what schedule keeps the behavior alive? A child on DRL-like wait training might speed up with a mild warning, while a child on FI-like token timing might slow down with the same cue. Adjust intensity and watch the baseline, not just the behavior.
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02At a glance
03Original abstract
Rats were exposed to a multiple schedule of reinforcement. During one component, a bar-press was followed by reinforcement only if it occurred between 15 and 20 sec after the previous response. This differential-reinforcement-of-low-rate (DRL) schedule produced a typical slow rate of responding. During the other component, reinforcement followed the first response to be emitted during limited periods of time which occurred at fixed intervals. These fixed-interval schedules with a limited hold produced higher response rates, described as ;interval' or ;ratio-like' behavior. Responding during the DRL component increased in frequency during a tone which ended with an unavoidable shock of low intensity, but decreased during the tone when the shock intensity was raised. The ;interval' and ;ratio-like' responding decreased in frequency during the tone at all shock intensities. Initial acceleration of the DRL responding appeared to be due to adventitious punishment of collateral behavior which was observed between the bar-presses. The more severe conditioned suppression during the fixed-interval components might be the result of the lower probability of reinforcement after any single response.
Journal of the experimental analysis of behavior, 1968 · doi:10.1901/jeab.1968.11-53