Continuous punishment of free-operant avoidance in the rat.
Start punishment at an effective level right away; gradual increases only delay suppression.
01Research in Context
What this study did
Scientists shocked rats every time they pressed a lever that normally prevented a bigger shock.
They wanted to see how fast this steady punishment would stop the lever pressing.
Some rats got strong shocks right away. Others got weaker shocks that grew stronger over time.
What they found
All rats stopped pressing the lever. Strong shocks worked fastest.
Weak shocks that grew stronger took longer to stop the behavior.
How this fits with other research
Fontes et al. (2025) later showed punishment does not always work this simply. When rewards also change quickly, rats pick the side that pays better, even if it hurts more.
Santi (1978) added another twist. Punishment stops lean-reward behavior faster than rich-reward behavior. So the same shock can work or fail depending on how much reinforcement is already present.
Vukelich et al. (1971) showed that rats only add up punishment effects if they have first lived through periods with no shocks. Without those safe periods, the extra suppression does not happen.
Why it matters
For your clients, start with the lowest intensity that still works, but do not creep upward slowly if safety is at risk. Check what rewards keep the behavior alive; a strong reward stream can block punishment effects. Give the client times free from any punisher so new learning can build.
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If you must add a punisher, begin with the lowest intensity that produces immediate suppression instead of slowly raising it.
02At a glance
03Original abstract
Three groups of albino rats were trained under a free-operant avoidance (Sidman) procedure with equal shock-shock and response-shock intervals. After stable performance was achieved, the animals were concurrently exposed to a brief electric shock after each response. The procedures were as follows: Punishment Schedule I: punishment shock was introduced at an intensity approximately one quarter that of avoidance shock; increments of nearly this same size were made as stable performance was achieved at succeeding punishment shock intensities. Punishment Schedule II: punishment shock was introduced at approximately one-half the intensity of avoidance shock; after stable performance, punishment shock was increased to the same intensity as avoidance shock. Punishment Schedule III: punishment shock was introduced and maintained at the same intensity as avoidance shock. Punishment was continued for all groups until one of two suppression criteria was attained. All animals made fewer responses and received more avoidance shocks as a function of increasing punishment shock. Half of the animals under Punishment Schedule I required punishment shock higher than avoidance shock to meet their assigned suppression criterion. A comparison of all procedures showed that suppression was greater when punishment shock was initially at high intensity.
Journal of the experimental analysis of behavior, 1969 · doi:10.1901/jeab.1969.12-149