Adjusting delay to reinforcement: comparing choice in pigeons and humans.
Indifference functions of amount and delay of reinforcement were compared for pigeon and human subjects by using Mazur's (1987) adjusting delay procedure. A model similar to the matching law (the simple reciprocal model), a hyperbolic model, three modified versions of the hyperbolic model, and a negative exponential model were evaluated. In Experiment 1 the subjects were pigeons, and in Experiments 2 and 3 the subjects were humans. In order to make the nonhuman and human situations more comparable, in Experiments 2 and 3 the reinforcer (points exchangeable for money) was discounted at a constant rate during the delay periods. The rate of this discounting varied between Experiments 2 and 3. The results of all three experiments demonstrated that a power function transformation of the hyperbolic model (in which 1 is added to the delays in the denominator of the simple reciprocal model) provided the best description of both nonhuman and human data.
Rodriguez
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ML
State University of New York, Stony Brook.
Logue
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AW
D000818:Animals; D002755:Choice Behavior; D010856:Columbidae; D005260:Female; D006801:Humans; D008433:Mathematics; D008960:Models, Psychological; D012055:Reinforcement Schedule; D012054:Reinforcement, Psychology; D013997:Time Factors