This study examined whether gambling behavior under conditions of diminishing returns differed between participants with histories of contingent (CD group) and noncontingent (NCD group) token delivery. In Phase 1, CD participants accrued tokens by correctly completing a discrimination task; for NCD participants, token accrual was yoked to token delivery of CD participants. In Phase 2, participants could choose to gamble their tokens or end the experiment and exchange their tokens for money. During the gambling task, participants could bet one token per trial. The probability of losses began at 10% and increased incrementally across blocks of 10 trials up to 100%. Overall, participants in the CD group gambled on fewer trials than participants in the NCD group. Costs of token accrual during Phase 1, in terms of number of trials and duration, showed a positive correlation with net tokens for the CD group but not the NCD group. Results are consistent with previous research demonstrating the value-enhancing effects of both prior contingent delivery and effort, and offer evidence that these histories influence sensitivity to loss.
Keywords: gambling; reinforcer value; stimulus value; within-trial contrast.