Concurrent performances: a baseline for the study of conditioned anxiety.
Two levers paying on separate clocks let you see fear as a drop on only the better lever.
01Research in Context
What this study did
Three lab rats faced two levers at once.
Each lever paid food on its own timer.
A buzzer sometimes came before a quick shock.
The team watched which lever the rats used less when the scary buzzer sounded.
What they found
When the buzzer played, rats stayed away from the lever they liked most.
The drop only showed on the better lever; the other stayed the same.
This split drop gives a clear picture of fear inside a two-choice setup.
How this fits with other research
LeBlanc et al. (2003) used the same two-lever rig but swapped shocks for richer snacks.
They showed choice can flip when one side links to better pay, not pain.
Richling et al. (2019) also doubt a rule we trust daily: 80 % right for three days may not keep skills.
Both papers push you to test, not trust, the old mark—whether for fear or mastery.
Why it matters
Use two easy tasks at once to spot fear side effects in real time.
If one task drops while the other holds, you have clean proof the client feels stress, not just fatigue.
Next time you probe for conditioned fear, run two reinforcers and watch which one dips.
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Join Free →Set two easy button games side-by-side; note which one dips when a new loud stimulus starts.
02At a glance
03Original abstract
Three rats were trained to lever press on concurrent random interval 2-min random interval 2-min schedules of milk reinforcement. With a 5-sec changeover delay, relative response rate matched the relative reinforcement duration associated with each lever. A stimulus, during which unavoidable shocks occurred at random intervals, was superimposed on this concurrent baseline, and shifts in preference were found. However, data from this procedure were ambiguous, apparently confounded by shock-elicited response bursts. Termination of the shocks during the stimulus resulted in a rapid recovery of matching, which was preceded by a brief facilitation of responding on the less-preferred lever. The procedure was then changed to a conventional conditioned anxiety paradigm with a variable duration pre-shock stimulus. A marked shift in relative response rate towards the preferred lever was found in all three rats; that is, responding on the preferred lever was far less suppressed during the pre-shock stimulus than responding on the less-preferred lever.
Journal of the experimental analysis of behavior, 1972 · doi:10.1901/jeab.1972.18-287