Gambling is a popular activity for many individuals, but a subset of players can develop severe gambling-related problems that can lead to mounting financial debt, problems with interpersonal relationships and work, and even involvement in criminal activities. Slot machines, in particular, can be especially alluring and result in dangerous gambling behaviors that lead to these adverse outcomes. Therefore, it is important to understand what aspects of slot play are most appealing to gamblers in order to reduce the negative impact that this type of gambling can have on individuals and society at large.
The original slot machine used a revolving mechanical reel to display and determine outcomes, but the introduction of microprocessors allowed manufacturers to use software to assign different probabilities to each individual symbol on each reel. This enables them to make it appear that a certain symbol was so close that it must be a winner, whereas the actual probability of hitting that symbol is significantly lower. Likewise, modern digital slot machines allow for more sophisticated bonus rounds and varied video graphics. While some manufacturers retain a lever as a skeuomorphic design trait, most are now operated via buttons or touchscreens.
When a player activates a slot machine, they can deposit cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode. The machine then activates reels that spin and rearrange symbols to form combinations, generating credits based on the paytable. The symbols vary from machine to machine, but classic symbols include fruits, bells and stylized lucky sevens. Most slot games have a theme, and the symbols and bonus features are aligned with that theme.
Participants completed a short personality and gambling questionnaire (CPGI), and a battery of behavioral measures during three slots sessions that were spaced 6-8 days apart. The tasks produced behavioral transcripts that allowed us to analyze in-game characteristics of gambling behavior, including the current credit balance and the magnitude of any recent win or loss. The task also allowed us to detect the onset of gambling-related positive emotions, or dark flow, and to measure the duration of post-reinforcement pauses, which are thought to be an index of habit formation.
The results suggest that the enjoyment associated with playing slots is primarily due to dark flow, and this effect was stronger when the participant experienced a recent win compared to a loss. Additionally, the length of the post-reinforcement pause was correlated with gambling impulsivity and previous experience with gambling. Moreover, these findings support the hypothesis that a gradual onset of gambling-related impulsivity and habit formation may contribute to the occurrence of harmful gambling behaviors. The data presented here will be useful for designing interventions to mitigate the detrimental effects of slot machine gaming. However, further research is needed to evaluate the effectiveness of these strategies. Ideally, such studies will provide more specific information on how to best help problematic gamblers overcome their addictions and achieve recovery. This will be crucial for developing targeted and effective intervention strategies for the tens of millions of people around the world who struggle with this debilitating problem.
