A slot is a game of chance with spinning reels and symbols that display winning combinations. These combinations are determined by a random number generator (RNG) that produces a different set of numbers every millisecond. The number of possible combinations is limited only by the amount of space on a physical reel and by the fact that each spin is independent of any previous results.
A player inserts cash or, in “ticket-in, ticket-out” machines, a paper ticket with a barcode into a slot and activates it by pressing a lever or button (either physical or on a touchscreen). The reels then stop to rearrange themselves, and if the symbol match a payline, the player earns credits according to the payout table. Modern electronic slot machines accept multiple currencies and can display up to 1024 paylines.
A key contribution of the authors is a new psychophysiological measure of reward reactivity that avoids cumbersome electrodes and wires that reduce ecological validity and inhibit flow. Unlike previous measures, this one does not require the player to think about their win or loss; it is triggered by auditory and visual feedback generated by the machine after a successful spin. Moreover, it provides robust estimates of the extent to which the rewards from different types of slots differ. This information can be used to inform the design of online slot games and increase their entertainment value. For example, it might be important to design a slot with higher volatility, where wins are less frequent but larger.