Return rates of online slot machines in trial mode influence players’ errors of estimation

Abstract

In the present study, we aimed to evaluate the impact of an exaggerated return rate on players’ errors of estimation and irrational beliefs. Conventional return rates for slot machines are set around 92%, whereas online gambling websites often use much higher return rates during demonstration (demo) play. Seventy college students were randomly assigned to play a virtual slot machine programmed to reflect a 92% return rate (control group) or a 180% return rate (experimental group). They completed self-reported measures of errors of estimation (e.g., chances of winning and losing) and irrational beliefs (e.g., having already won guarantees future wins) before and after playing a virtual slot machine for 10 min. Results from mixed 2 x 2 analyses of variance revealed statistically significant differences in errors of estimation (i.e., chances of winning, chances of winning the jackpot, chances of neither winning nor losing) between the experimental and control groups. Furthermore, participants estimated having less chance of losing during a slot machine session after exposure to the exaggerated return rate. Given the fact that many online gambling websites use similar exaggerated return rates during the demo period of their virtual slot machines, the present results suggest that this tactic may incite players to behave differently than they would otherwise during a gambling session. Implications for responsible gambling strategies are discussed.