In a slot machine, players insert cash or, in “ticket-in, ticket-out” machines, paper tickets with barcodes, and activate a reel mechanism to rearrange the symbols. When the symbols line up on a pay line, the player earns credits according to the payout table displayed on the machine’s screen. A modern video slot machine may also incorporate a random number generator (RNG) to ensure random results. Depending on the type of game, the symbols used can vary from classic fruits and bells to stylized lucky sevens. Most slot games have a theme, and the symbols and bonus features are aligned with that theme.
Historically, all slot machines utilized revolving mechanical reels to display and determine outcomes. While this system was efficient and relatively reliable, the limited number of physical symbols available to each reel severely limited jackpot sizes and possible combinations. In the 1980s, manufacturers began to rely on microprocessors in their machines to create new possibilities. These microprocessors enabled manufacturers to program each symbol with a different probability of appearing on the display screen. The new probability was not directly proportional to the number of times the symbol had landed on the reel, but rather it was weighted by the machine’s electronics.
Our study tests the hypothesis that sounds amplify the positive affect associated with winning in slots. By using a slot machine simulator with sound-on and sound-off conditions, we find that sound-accompanied wins are perceived as significantly more frequent than losses disguised as wins. This is largely due to the fact that the sound of a win can cause players to overestimate their frequency of wins, even in the absence of any actual wins.