Magnitude, delay and probability of reinforcer in hypothetical risk situations

The present study investigated the effects of reinforcement magnitude of the risk alternative and different instructions on the subjective reinforcement value. Eight undergraduate students made hypothetical choices between certain immediate amounts of money that were adjusted according to the subjects' behavior, and larger amounts (V = R$10,00 to R$100.000,00) with several delays (one week to 50 years) or probabilities (0,05 to 0,95) associated to V. The positive instruction described the odds or waiting time to gain each amount of money, while the negative instruction described the odds against or the waiting time for not loosing the money. The relative subjective value decreased with increase in the probable V, and increased with increase in the delayed V. Individual results were better described by a power function than by an hyperbola. There was no systematic effect related to different instructions. The present results are evidences for a different interpretation about the effects of the reinforcement magnitude on the discount of probable or delayed amounts.

choice; decision-making; reinforcement probability; reinforcement amount; reinforcement delay