Do losses disguised as wins create a "sweet spot" for win overestimates in multiline slots play?

Multiline slots are popular electronic gaming machines. Research suggests that particular outcomes on these games, namely losses disguised as a wins or LDWs, may make these games particularly alluring to gamblers. LDWs occur when one wins less than they wager, but the machine celebrates these net losses with flashing lines and winning sounds (e.g., bet a dollar, win back a dime). Players are known to somatically, psychologically, and behaviourlly miscategorize LDWs as wins rather than losses. Furthermore, LDWs lead players to overestimate how many times they thought they won during a playing session - leading to what is known as the LDW-triggered win-overestimation effect. In this paper, we analyzed experienced players' win-overestimates from 13 studies after playing slots with different LDW percentages. The combined data showed an inverted U-shaped function for win-overestimates. There appears to be a "sweet spot" for the LDW-triggered win-overestimation effect; wherein, a moderate number of LDWs maximizes this effect, but a high number of LDWs decreases the effect. In Study 2, we confirmed with 132 experienced gamblers that there appears to be maximal win overestimates at around 19.6% LDWs. We conjecture that a high number of LDWs may lead players to see a disconnection between the running total on the machine going down and the number of "wins", leading to more accurate win estimates. This inverted "U" effect for win-overestimates parallels previous research showing that gamblers continue to play for longer during a losing streak following a playing session with a moderate (versus low or high) number of LDWs. LDW-triggered win-overestimates may contribute to the allure of multiline slots -games that cause significant problems for a subset of gamblers.