"Losses disguised as wins" in electronic gambling machines contribute to win overestimation in a large online sample

Losses disguised as wins (LDWs) are a salient type of losing outcome common to electronic gambling machines (EGMs). These events occur when a gambling payout is less than the amount wagered (i.e., a net loss) but is nonetheless accompanied by the sounds and animations that accompany genuine wins. Previous lab-based studies have reported that participants tend to overestimate genuine wins when LDWs are present. This study reports an independent replication of these findings in a large online sample that included a substantial number of individuals reporting high-risk gambling and frequent EGM users.

This online study recruited a sample of 940 participants who were randomly assigned to view one of two brief videos. Each video displayed a short period of simulated online slot machine gambling and included 2 genuine wins and either 3 or 0 LDWs. Participants were asked to estimate the number of times a win occurred that was more than the amount bet. Participants also completed the Problem Gambling Severity Index.

The mean estimated number of genuine wins was significantly larger for the condition displaying LDWs, 3.02 [95% CI = 2.82, 3.21] than the control condition, 2.14 [1.98, 2.30], t(887.66) = 6.78, d = 0.44, p <.001.

We replicated the LDW-triggered win overestimation effect previously reported in lab-based experiments that have recruited smaller samples. This effect was robust in both low-risk and high-risk groups, indicating that even experienced gamblers remain susceptible. Exploratory modelling suggested only a minority of individuals were uninfluenced by LDWs.