Lever attacking by rats during free-operant avoidance.
Post-shock bursts in avoidance tasks can be reflexive attacks, not evidence of learning.
01Research in Context
What this study did
Researchers watched rats press a lever to avoid shocks.
They also recorded any biting of the lever itself.
The setup was free-operant avoidance: no warning beep, just shocks that could be postponed by lever presses.
What they found
After each shock, rats often bit the lever hard.
These bites looked like extra "responses" on the data sheet.
The team realized the bites were reflex attacks, not attempts to avoid more shocks.
How this fits with other research
Farmer et al. (1966) ran the same lever-press avoidance task but never noted biting.
Their clean data may have hidden reflex attacks that were counted as avoidance responses.
Lambert et al. (1973) later showed avoidance still works even if the lever press itself gives a shock.
This supports the idea that shock-frequency reduction, not reflex biting, drives true avoidance.
Why it matters
When you see a sudden burst of responses after an aversive event, ask: is it operant avoidance or a reflex?
Check the form of the response—biting, flinching, or other reflexive topographies may inflate your data.
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02At a glance
03Original abstract
Rats pressed a lever to avoid shock on a free-operant avoidance schedule. Some subjects were also exposed to extinction in which the response-shock contingency was eliminated while the shock-shock contingency remained in effect. A specially constructed lever was used that registered not only presses, but also biting attacks on the lever. Throughout various phases of the study, shocks often elicited lever biting as well as post-shock responding. The results suggested that shock-elicited attacks that are forceful enough to activate the operandum might account for some of the responding that occurs in experiments on free-operant avoidance behavior. In particular, shock-elicited operandum attacking might account for post-shock response bursting during free-operant avoidance and the extreme persistence of responding sometimes noted when shocks are delivered during the extinction of avoidance behavior. To the extent that this is true, these phenomena should not be characterized as operant behavior in interpreting the results of experiments on free operant avoidance.
Journal of the experimental analysis of behavior, 1972 · doi:10.1901/jeab.1972.18-517