Date of Award


Degree Name

Doctor of Philosophy



First Advisor

Dr. M. Kay Malott

Second Advisor

Dr. D. O. Lyon

Third Advisor

Dr. R. R. Hutchinson

Fourth Advisor

Dr. L. Supnick


A response initially produced by noncontigent fixed-time delivery of brief electric shock was strengthened by reinforcement. Following the fixed-time shock baseline condition, response contingent shock absence (avoidance) was programmed for the lower probability of two response options for one group of squirrel monkeys. For the other group the interposed history was variable-interval food reinforcement. When responding was reliably maintained reinforcement was discontinued and a return made to fixed-time shock conditions as programmed prior to reinforcement. Upon a return to original conditions, rates were substantially elevated over baseline with the elevation sustained for many sessions. The avoidance group showed the most dramatic effects with rate increases on the manipuladum for which reinforcement had been programmed as well as a large rate increase on the manipulandum for which no reinforcement was provided. The present findings confirm previous work in showing substantial and continuing rate enhancement effects of reinforcement in the absence of current contingencies.

Access Setting

Dissertation-Open Access

Included in

Psychology Commons