A narrow notch, groove, or opening, as a keyway in a machine or container, or a slit for a coin in a vending machine. Also, a position in a group, series, or sequence.

In gambling, slot machines create ‘near miss’ outcomes: losses that appear close to jackpots. Such near-miss stimuli can lead to prolonged play and heavier losses. This is an example of conditional reinforcement, as discussed by B.F. Skinner in 1953.

The cost of playing casino slots is often hidden from patrons, who assume that they are only making a small wager per spin and spending a limited number of hours per week. But this activity can actually be more expensive than going to a movie or concert, and can quickly spiral out of control for people with severe problems. The loss of a job or home is another potential outcome for those who spend too much time on slots. Bringing slots to Massachusetts without also working to ameliorate their harms would have serious consequences for the state. For many of these people, the losses are disguised as a win, and the money spent on slots is often far more than it could afford. This is a form of predatory lending and should be forbidden. The best current research shows that casinos with slots have a high potential for negative effects on communities. This includes the risk of gambling addiction, and a high likelihood that children in those communities will be exposed to addictive behaviors and learn to gamble as adults.