What is a Slot?

An opening, hole, or groove in which something can be inserted or fitted. Also called a slit, slot, or pocket. (Dictionary of American English, 1998).

Slot was invented in 1909 by Charles Fey for the Industry Novelty Company to circumvent San Francisco laws against gambling machines. Unlike the earlier Sittman and Pitt invention, Fey’s machine had three reels and allowed automatic payouts. In addition to standard poker symbols, Fey included on the reels pictures of diamonds, spades, horseshoes, hearts, and liberty bells (which became the universal symbol for slot). In an attempt to further circumvent law, he called his machines chewing gum dispensers and added fruit-themed symbols to the spinners.

Modern slot machines are programmed to weigh particular symbols more than others, and to allow only a limited number of combinations on a given payline. These are designed to maximize the number of wins, and thus player enjoyment, while minimizing losses. This approach to slots design is often referred to as “taste” and it is used to keep players betting and engaged.

While it is generally understood that the frequency of wins and losses determines players’ engagement with a game, other factors may play a role as well. In this study we report two new measures of reward reactivity that gauge how much players enjoy playing slots. Unlike other psychophysiological measures involving cumbersome electrodes and wires that likely reduce ecological validity and inhibit flow, these measures can be extracted from video recordings of slot play without the need for any equipment.