Shull, R. L. & Grimes, J. A. (2006).
Resistance to extinction following variable-interval reinforcement: Reinforcer
rate and amount.
Journal of the Experimental Analysis of Behavior, 85, 23-
39.
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Rats obtained food-pellet reinforcers by nose poking a lighted key. Experiment 1
examined resistance to extinction following single-schedule training with
different variable-interval schedules, ranging from a mean interval of 16 min to
0.25 min. That is, for each schedule, the rats received 20 consecutive daily
baseline sessions and then a session of extinction (i.e., no reinforcers).
Resistance to extinction (decline in response rate relative to baseline) was
negatively related to the rate of reinforcers obtained during baseline, a
relation analogous to the partial-reinforcement-extinction effect. A positive
relation between these variables emerged, however, when the unit of extinction
was taken as the mean interreinforcer interval that had been in effect during
training (i.e., as an omitted reinforcer during extinction). In a second
experiment, rats received blocks of training sessions, all with the same
variable-interval schedule but with a reinforcer of four pellets for some blocks
and one pellet for others. Resistance to extinction was greater following
training with the larger (four pellets) than with the smaller (one pellet)
reinforcer. Taken together, these results support the principle that greater
reinforcement during training (e.g., higher rate or larger amount) engenders
greater resistance to extinction even when the different conditions of
reinforcement are varied between blocks of sessions.
Key words: resistance to extinction, reinforcer rate, reinforcer amount,
behavioral momentum, omitted reinforcers, key poke, rats