The maintenance of escape behavior under fixed-ratio reinforcement.

Abstract

Termination of an aversive stimulus by a fixed number of skeletal responses has been termed fixed-ratio reinforcement of escape behavior. Under aversive light of 183 mL. with pedal-pressing as escape response, the properties of this behavior were examined in male Wistar albino rats in a specially constructed apparatus, for fixed ratios ranging from 1:1 to 30:1. In an initial three hours of training, each response in light terminated the light for 1.0 min. Then, over successive experimental sessions, the number of pedal-presses required to stop the light was gradually increased, with a minimum of five sessions for each fixed ratio examined. Chief findings are: (1) Following onset of the aversive stimulus, there tends to be a period of no response, after which the escape response is emitted at a rapid rate. (2) The aversive stimulus appears to exert a discriminative as well as a negatively-reinforcing control over fixed-ratio escape responding. (3) As the fixed ratio increases, latency of the first escape response increases exponentially; rate of escape responding tends to in-crease; and responding in the absence of the aversive stimulus tends to decline.