A slot is a narrow opening for receiving or admitting something, such as a coin or letter. A slot in a computer is a position or area within a construction into which one of a set of morphemes can be fit.

A casino slot machine is a gambling device that uses a random number generator (RNG) to display symbols on a set of reels when the player presses the spin button. When the symbols line up on a winning payline, the player receives a payout based on the amount wagered and the coin denomination. Some slot machines have additional features, such as a scatter symbol or a wild multiplier.

Although the majority of gamblers are recreational players who enjoy gambling as harmless entertainment, a small but significant subset can experience serious gambling-related problems (Blaszczynski, Sharpe, Walker, Shannon, & Coughlan, 2005). These issues can lead to financial debt, emotional distress, and difficulty maintaining relationships and careers.

In order to understand the allure of slots, we investigated how they influence the processing of reward in the brain. To do this, we examined how PRPs and force (a measure of reward reactivity as a function of win size) relate to enjoyment of slot games. Unlike psychophysiological measures that require cumbersome electrodes and wires that decrease ecological validity and inhibit flow, these measures of reward reactivity were elicited while participants played a multiline slot machine.

We found that both PRPs and force were positively associated with unique positive affect variance in a multiple regression framework when dark flow was included. However, only PRPs were significantly correlated with wins and losses. Hence, our results suggest that PRPs and force may be two distinct dimensions of enjoyment, with wins being more enjoyable than losses.