Studies have evaluated a range of interventions to treat food selectivity in children with autism and related developmental disabilities. The high-probability instructional sequence is one intervention with variable results in this area. We evaluated the effectiveness of a high-probability sequence using 3 presentations of a preferred food on…

The delivery of food contingent on 10 s of consecutive toy engagement resulted in a decrease in engagement and a corresponding increase in other responses that had been previously reinforced with food. Similar effects were not observed when tokens exchangeable for the same food were delivered, suggesting that engagement was disrupted by the…

Four pigeons were trained on two-key concurrent variable-interval schedules with no changeover delay. In Phase 1, relative reinforcers on the two alternatives were varied over five conditions from 0.1 to 0.9. In Phases 2 and 3, we instituted a molar feedback function between relative choice in an interreinforcer interval and the probability of…

Radical behaviorism considers private events to be a part of ongoing observable behavior and to share the properties of public events. Although private events cannot be measured directly, their roles in overt action can be inferred from mathematical models that relate private responses to external stimuli and reinforcers according to the same…

Two experiments examined how pigeons differentiate response patterns along the dimension of number. In Experiment 1, 5 pigeons received food after pecking the left key at least N times and then switching to the right key (Mechner's Fixed Consecutive Number schedule). Parameter N varied across conditions from 4 to 32. Results showed that run length…

When behavior suggests that the value of a reinforcer depends inversely on the value of the events that precede or follow it, the behavior has been described as a "contrast" effect. Three major forms of contrast have been studied: "incentive contrast," in which a downward (or upward) shift in the magnitude of reinforcement produces a relatively…