The present study determined if altering the unsignaled delay to reinforcement would alter the within-session pattern of responding. In both Experiments 1 and 2, 4 rats pressed a lever for reinforcers delivered by a variable-interval schedule during 50-min sessions. Across conditions, the value of the variable-interval schedule' was either 15 or 60 s and the unsignaled delay to reinforcement was 0.04, 0.20, 1.00, 5.00, or 25.00 s. Food-pellet reinforcers were delivered in Experiment 1 and 5% liquid-sucrose reinforcers were delivered in Experiment 2. Increasing the delay to reinforcement altered both response rates and response patterns, except when sucrose reinforcers were delivered by a variable interval 60-s schedule. These results may pose problems for some theories of delayed reinforcement. Perhaps more importantly, they indicate that procedural aspects can potentially influence conclusions made about the effect of delayed reinforcement.
Weatherly, Jeffrey N.; Stout, Jason E.; Rue, Hanna C.; and Melville, Cam L.
"Effect of Unsignaled Delay to Reinforcement on Within-Session Responding,"
The Psychological Record: Vol. 50
, Article 9.
Available at: http://opensiuc.lib.siu.edu/tpr/vol50/iss2/9