Slot is a game of chance that relies on the fundamentals of probability and employs a complex array of mechanics to disguise the fact that winning and losing are nearly random events. This unique combination of engineering acumen, mathematical knowledge and psychological deceit makes slot games popular with millions of players worldwide. Unlike many other forms of gambling, slots offer immediate feedback on the outcome of each spin and their monetary gains are often accompanied by high-fidelity attention-grabbing sounds and animations (Griffiths and Parke, 2005).
In order to understand why people like to play slot, it is important to look at the way they perceive and process rewards. A simple measure of reward reactivity can be obtained by using the Physiological Reward Points (PRP) scale. However, the method has a number of limitations and is susceptible to biases. To overcome these problems, a more objective measure of reward reactivity has been developed. The force measurement uses the rate of change in heart rate, which is a strong predictor of positive affect, and it also controls for the effects of negative emotions (Loba et al., 2001).
The nine-line realistic simulator used in this study replicated the visual and auditory components of commercially available slot machines. When the result of a spin was a loss, the pay line counter showed 0, while in wins it sequentially flashed rising digits corresponding to the credits won on that spin. The simulator was accompanied by a musical instrument-themed soundtrack. In the sound-on condition, players on average overestimated the number of times they won when compared with a control group who played in the sound-off condition.
A significant effect of sound on arousal was found, with players experiencing more arousal when the machine produced a win than when it did not. This effect was mediated by a reduction in the negative emotions associated with gambling, particularly depression and anxiety. However, the use of PRPs and the force measure did not explain any of the negative associations of slot machine play. These results suggest that other variables, such as the amount of money won, may be more important in predicting gambling behavior.
Although newer slot machines have added features such as more reels, different pay lines and interactive games, the basic architecture of a modern slot machine is still quite similar to its nineteenth century predecessor. A computer chip containing a Random Number Generator generates thousands of three-number combinations every second and drives the mechanical parts of the machine. When the reels stop, the machine determines whether to award a win or a loss, and then signals the player to press the start button again. A winning combination of symbols is displayed on the screen and a celebratory sound and animation are generated. The more extensive the celebratory sound, the larger the payout. The sexy, attractive appearance of the machine and its high-fidelity, attention-grabbing soundtrack contribute to its appeal. Despite these features, slot games remain highly addictive and are among the most popular forms of gambling.
