Does Delay of Reinforcement Produce Durable Persistence?

In a foru-phase experiment, phase I was runway training under four different reinforcement conditions: partial reinforcement (PRF), partial delayed reinforcement (PDR), constant delayed reinforcement (CDR), and consistent reinforcement (CRF). During phase 2 extinction, PRF and PDR groups did not differ; both groups were more persistent than group CDR, which was in turn superior to the CRF control. Phase 3 was CRF reacquisition for all groups. During phase 4 extinction, PRF group was more presistent than the other three groups which did not differ. A Pavlovian counter-conditioning hypothesis was proposed to account for the absence of durable persistence following PDR training.

Reinforcing Properties of Nonnutritive Sweeteners in Dry Compound

Previous research on the reinforcing properties of saccharin used saccharin in solution with water, a primary reinforcer. In the present study rats were given extensive runway training with dry pellets containing sodium saccharin combined with purified kaolin. Even after 250 trials, neither the runway response nor the consummatory response showed any evidence of extinction.

Secondary Reinforcement Based on Primary Brain Stimulation Reward

15 rats were trained to run in a straight runway for rewarding brain stimulation (ESB). A consistent color of goal box—ESB reward pairing existed during runway training. When subsequently rested in a T-maze where the goal box associated with ESB was placed on the initially nonpreferred side, Ss learned to run to that side with only the goal-box color as the reward. The results are held to conclusively demonstrate that secondary reward can be based on ESB as a primary reward. Also, results appear to challenge the view that drive is necessary for the demonstration of secondary reward.

Replication Report: Absence of a Successive Contrast Effect on Instrumental Running Behavior after a Shift in Sucrose Concentration

Two groups of 16 rats were given several sessions of rewarded placements into the goal box prior to instrumental runway training. Group 4% received 4% sucrose solution and Group 36% received 36% sucrose solution upon each consummatory-experience placement. Both groups then were given 48, partially-reinforced (50%), instrumental trials with 36% sucrose solution as reward. No contrast effect was found as Group 36% ran faster than Group 4% throughout instrumental training.