The effect of rate of delivery of response-independent shocks upon avoidance responding.
Avoidance can survive on scraps of relief, so gradual thinning beats cold-turkey removal.
01Research in Context
What this study did
Researchers set up a lab box with a lever and a shock grid. Monkeys could press the lever to delay shocks, but extra shocks also arrived no matter what they did.
They slowly turned up the rate of these free, response-independent shocks. The team watched how often the monkeys still pressed the lever.
What they found
At first, more free shocks made the monkeys press faster. When the free shocks kept coming even faster, pressing dropped but never stopped.
Even when only 15 percent of shocks could be avoided, the monkeys kept pressing. The behavior had stuck.
How this fits with other research
Peterson (1968) showed the same thing a year earlier: monkeys keep pressing while the real shock count is dropping. Once the drop stops, pressing stops. Jones (1969) adds the twist that pressing can linger even when most shocks are now unavoidable.
Hineline (1970) pushed the idea further. Lever presses still happened when they only delayed shocks without cutting the total number. Together, the three studies show avoidance can survive on tiny or even imaginary savings.
Cullinan et al. (2001) flipped the valence. Rats earned food pellets, then got free milk that had nothing to do with pressing. The extra free milk also made the lever press harder to extinguish. Free events, good or bad, glue behavior in place.
Why it matters
Your client's escape or avoidance behavior may keep running even when it hardly pays off. Check if tiny, occasional payoffs are still in play. Fade them slowly instead of assuming 'almost zero' equals zero.
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02At a glance
03Original abstract
Two hooded rats were trained to bar-press to avoid electric shock on a continuous avoidance schedule with response-shock and shock-shock intervals equal. The rate of delivery of response-independent shocks superimposed on this schedule was varied. The response-independent shocks led to generally higher response rates but, with responses during shock omitted, the rates decreased as the response-independent shock rate was increased. The actual shock rate received by the subjects was linearly related to the maximum potential shock rate. There was an increasing, negatively accelerated function between percentage avoidance and response rate, but there was no consistent relation between the number of shocks avoided and response rate. Response rate decreased as the potential shock rate increased, but responding was maintained even when as few as 15% of the shocks could be avoided.
Journal of the experimental analysis of behavior, 1969 · doi:10.1901/jeab.1969.12-1023