House-edge information and a volatility warning lead to reduced gambling expenditure: Potential improvements to return-to-player percentages.

Cost-of-play information is one public health intervention recommended to help reduce gambling-related harm. In the UK, this information is given on electronic gambling machines in a format known as the "return-to-player", e.g., "This game has an average percentage payout of 90%." However, previous evidence suggests that this information could be improved by equivalently restating it in terms of the "house-edge", e.g., "This game keeps 10% of all money bet on average." A "volatility warning," stating that this information applies only in the statistical long-run, has also been recommended to help gamblers understand cost-of-play information. However, there is no evidence comparing these information provisions' effect on gamblers' behavior. An experiment tested US gamblers'(N = 2433) incentivized behavior in an online slot machine, where this information was manipulated between-participants along with a counter showing the total amount bet. Preregistered analyses showed that participants gambled significantly less when house-edge information or a volatility warning were shown compared to standard return-to-player information, with no effect of the total amount bet counter, and no significant interaction effects. However, these significant findings had small effect sizes, suggesting that a public health approach to gambling should not rely on informational provisions only. Subject to supportive evidence from more ecologically-valid designs such as field studies, these results suggest that improved cost-of-play information could lead to reduced rates of gambling expenditure and therefore benefit a public health approach to gambling.

Making EGMs Accountable: Can an Informative and Dynamic Interface Help Players Self-regulate?

Electronic gaming machines (EGMs) are recognised as one of the most harmful gambling forms, because they promote high-speed repetitive gambling and automatically reinvest winnings. These features, amongst others, make it difficult for EGM gamblers to keep track of their play. Tools to assist gamblers exist, but have limited effectiveness because they require user registration and manual activation, leading to low uptake. The present study aimed to evaluate the effect of a more informative interface (including removal of automatic reinvestment of winnings) and pop-up messages on gambling behaviour, and on player experience. A total of 213 Australian participants, recruited through social media, played a simulated online EGM. The experiment was a two (standard vs. informative interface) × two (pop-ups absent vs. present) between-subjects design. The informative interface: promoted keeping track of spins played; increased accurate estimation of amount spent (as did pop-up messages) and time played; and provided game usage figures which acted as cues to quit play. Once the initial deposit (but not winnings) was expended, informative interface users could opt to reinvest their winnings, although many opted to exit at that point. No difference in total spending or dissociation was observed between experimental groups. Informative interface users reported no reduction in enjoyment. Pop-up messages reduced enjoyment with the standard interface, but increased enjoyment when paired with an informative interface. These findings indicate that a more informative interface and pop-up messages may be useful in reducing the harmful nature of EGMs.