A narrow notch, groove, or opening, as a keyway in a piece of machinery or a slit for coins in a vending machine.

For example, a slot could be a slot on a computer keyboard or the space used for one of the keys on a typewriter keyboard. It could also refer to the space on a screen where an image is displayed.

The sight and sound of winning on a slot machine may increase the desire to play and the memories of previous wins, according to University of Alberta researchers. The team of psychologists found that people who played a virtual slot machine with casino-related stimuli—such as the sounds of coins dropping and symbols of dollar signs—were more likely to continue playing the game than those who did not.

Although numerous experimental studies have supposedly shown that near-miss events reinforce gambling persistence, few of these experiments have demonstrated this effect explicitly. Moreover, conventional chained procedures that successfully produce conditional reinforcement have some logical predictability between the putative conditional reinforcer and the subsequent unconditional reinforcer. In contrast, classic slot machines provide random outcomes with no contingency between the occurrence of near-miss stimuli and the occurrence of a winning outcome.

Similarly, the experimental designs of the most cited studies use relatively simple stimuli that are less complex than those of typical slot machines. Such simplified stimuli might limit unsystematic variation and make learning of the underlying contingencies more straightforward. However, this might also prevent a more precise test of the hypothesis that near-miss stimuli are a form of reinforcing feedback.