Examining the Illusion of Control via Outcome Sequences in Online Slot Machine Gambling

Background: The illusion of control is a cognitive bias where individuals overestimate their personal influence over random events. Prior research indicates that the sequence of outcomes can shape this illusion, with early wins (a ‘Descending’ sequence) strengthening the illusion of control more than late wins (an ‘Ascending’ sequence) or evenly distributed (‘Flat’) wins.Method: Over two pre-registered experiments, we tested how outcome sequences affected peoples' perceptions of control in an online slot machine task, hypothesizing that a Descending win sequence would create the strongest perceived control ratings, increased bet size, and faster spin initiation. In Study 1, the wins and losses were uniform, while in Study 2, different symbol combinations were associated with different win sizes.Results: In Study 1, the Descending condition was associated with significantly higher perceived control total scores than the Ascending condition. Higher perceived control ratings were associated with higher bet sizes, but not with faster spin initiation. In Study 2, there were no differences on the perceived control total score across conditions, nor was perceived control associated with bet size, but the Descending condition was associated with higher perceived control ratings on the specific items that were sensitive in Study 1.Conclusions: The findings of Study 1 extend prior research on outcome sequences using simple coin-toss tasks to perceived control in an online slot machine setting. Contrary to our expectations, this effect was only partially supported when the size of the wins varied in Study 2.