A slot is a thin opening or groove in something, such as a door or window. A slot in a computer or other device is the mechanism by which data is read and processed. A slot is also a place where information can be stored. The term slot is also used for a position in a graphical display, such as an icon on a computer screen or a video game controller.

A slots game is based on spinning reels with symbols and the ability to earn credits when winning combinations line up on a payline. Unlike traditional mechanical machines, which use mechanical springs and levers to spin the reels, newer electronic slot games utilize random number generators (RNG) to determine where the symbols will land on each spin. A player inserts cash or, in the case of “ticket-in, ticket-out” machines, a paper ticket with a barcode into a slot on the machine to activate it. The reels then stop to rearrange the symbols, and the player earns credits based on the payout table.

In a study of slot-machine play, Dixon et al. found that dark flow accounted for some of the enjoyment associated with slot-machine play, but that some enjoyment is not attributed to dark flow and may be attributable to reward reactivity or other aspects of the gambling experience. Their measures of reward reactivity, PRP and force as a function of win size, were positively correlated with positive affect ratings during slot-machine play but were uncorrelated with depression scores.