The Effects of Machine Balance and Free-Spins Features on Machine Preference and Bet Amounts

Across two experiments, the current study investigated whether the balance displayed on slot-machine screens affects gamblers’ decision making in a manner similar to the “house-money effect” observed in other gambling modes. The balance indicates the total amount the gambler has available to wager from. We manipulated initial slot-machine balance within a simulated slot-machine task. Participants gambled on each of two machines and then were able to switch between the two allowing us to assess the effect of machine balance on both preference and bet amounts. Experiment 1 also manipulated which machine incorporated a free-spins feature. In both experiments participants preferred to wager on, and made larger bets on, machines with higher balances. Experiment 1 replicated previous findings that people prefer to gamble on machines offering free spins. Together, these two experiments identify balance available as an additional slot-machine feature that contributes to slot-machine gambling behavior.