Behavioral interaction under concurrent spaced-responding, variable-interval schedules of reinforcement

Prenatal methylmercury exposure increases responding under clocked and unclocked fixed interval schedules of reinforcement.

Recent experiments have suggested that developmental methylmercury exposure produces perseverative behavior in adulthood. In the present experiment, interactions between developmental low-level methylmercury (MeHg) and nutritionally relevant dietary selenium (Se) on operant behavior and its persistence were examined in aged animals. Female rats were exposed, in utero, to 0, 0.5, or 5 ppm mercur...

Concurrent drinking by pigeons on fixed-interval reinforcement schedules.

Three experienced pigeons were exposed to at least ten consecutive 100-min sessions on each of three food-reinforced fixed-interval (FI) schedules: FI 50-sec, FI 100-sec and FI 200-sec. Water was freely available. Drinking was largely confined to the first third of each fixed interval, and the mean sessional water intake was directly related to the food-reinforcement rate for each animal. The a...

Human responding on random-interval schedules of response-cost punishment: the role of reduced reinforcement density.

An experiment with adult humans investigated the effects of response-contingent money loss (response-cost punishment) on monetary-reinforced responding. A yoked-control procedure was used to separate the effects on responding of the response-cost contingency from the effects of reduced reinforcement density. Eight adults pressed buttons for money on a three-component multiple reinforcement sche...

Assessing Animals’ Preferences: Concurrent Schedules of Reinforcement

Mechanisms underlying the effects of unsignaled delayed reinforcement on key pecking of pigeons under variable-interval schedules.

Three experiments were conducted to test an interpretation of the response-rate-reducing effects of unsignaled nonresetting delays to reinforcement in pigeons. According to this interpretation, rates of key pecking decrease under these conditions because key pecks alternate with hopper-observing behavior. In Experiment 1, 4 pigeons pecked a food key that raised the hopper provided that pecks on...