Abstract
The extinction of non-discriminated avoidance behavior was examined in the rat under a two-lever concurrent avoidance-variable interval 30-sec. schedule. Avoidance responses decreased to a low rate when shocks were no longer given. However, a steady continuous rate on the “avoidance-extinction lever” persisted over the 10 mo. of training and increased (1) when responses on the variable interval schedule were punished, and (2) during the delivery of “free shocks.” Avoidance-extinction response rate was reduced (1) when the variable interval schedule was reduced to 15-sec., and, to a greater extent, (2) following avoidance lever removal when responses on the variable interval schedule were punished during this period. It was concluded that factors related both to the organism's history of aversive stimulation and to the interactions occurring between concurrent temporal schedules underlie the maintenance of avoidance responding observed under the present extinction conditions.
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