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Research Paper | The Secrets of Slot

Research Paper

Understanding Gaming Experience - MA Games Design, LCC

Su Kizilagac

10 January 2018


Slot is one of the top-grossing games in the world, and it has been one of the most popular attractions for more than a century. Even though slot play is considered as a gambling method, it would be more than fair to say that slot have a very successful game design. “The line between gambling and amusement was always thin” (Kurtz, 1991, p.8), and this is why understanding the slot gaming experience is important. Slot design influence the modern digital games and gamification practices of today. The design techniques, which are embodied by slot games, are precisely used for developing casual games with addictive play, such as match-three puzzle games (i.e. Candy Crush by King, Toon Blast by Peak Games Inc.) and incremental games (i.e. Cookie Clicker by Julien Thiennot, AdVenture Capitalist by Hyper Hippo Productions). Besides, they are used for enhancing the UX in social media or online social networking channels. This essay focuses on the slot machine gaming experience, and it aims to explain why slot play is so popular. In an attempt to unravel this enigma, first the essay will disclose how a slot machine operates, then it will describe the game’s psychological effects on players, and ultimately it will demonstrate the techniques incorporated in slot design.

Slot: Machines & Gameplay

The player objective in a slot game is to juice cash out of the machine by scoring many winning combinations. There is nothing much a player can do really, in order to reach the objective, other than adding in cash/credits, pressing spin and hoping to get lucky. The most distinctive attribute of a slot game is that there is no skill involved on the player's part what so ever. The chance of winning completely depends on pure luck, but the game may create the illusion of involving skill (Bourie, 2009).

A slot game generally features symbol matching. The symbols are displayed on reels, which spin and then stop to reveal the resulting combination (Bourie, 2009). The art style of the symbols are iconic, vivid and colourful. On the vintage machines, the reels would display easily recognised images such as cherries, plums and lemons; this led the slot machines to be called “fruit machines” in Britain (Kurtz, 1991).

Every slot machine has a RNG (Random Number Generator ) inside it. RNG is a computer chip which spits out random numbers by doing thousands of calculations per second (Bourie, 2009). Each of these numbers are represented by a symbol (i.e. 5 = cherry). When the player presses the spin button or pull the lever, the random number generated at that exact instant by the chip determines the combination of symbols to be displayed on the reels, and on the payline*, more specifically (Bourie, 2009). The slot machine adds on (winning) or takes away credits (loosing) depending on this resulting combination.

Most of the slot games have a variety of winning combinations, which can be seen from another screen on the machine. The player can educate himself, learn about these winning combinations and the rules of the game, but in reality his knowledge will not have any effect on win or loose states. The machine will operate by its own as long as there is enough credit to spend and the player keeps pushing the button (Bourie, 2009). On the other hand, the gained knowledge might enhance the gaming experience. The player can make sense of why he lost or won in each spin.

*Payline: the line on which the game’s resulting combination appears, and this combination is taken into consideration to determine a payout. There may be multiple paylines in a slot game.

Basically, a slot machine is made to randomly give away less money than the amount it takes in (Bourie, 2009). The chip inside it also determines the payout rate of a machine. The industry standard is between 85% (lowest rate) and 98% (highest rate). Denomination is the factor that regulates the pay pack ratios of each machine. Generally a penny machine is set to payback low since the initial player investment is low. A machine with high denomination is more likely to payback high, considering that each spin is more expensive to play. (Bourie, 2009). This doesn’t mean that a player who puts 100 £ in a machine with a payout rate of %95 will receive 95 £ back when he ends play. This rate represents the pay back ratio of several million plays in that machine, it is an average number to be reached in distant future (Bourie, 2009).

Psychology Behind the Slot Gaming Enthusiasm

There have been different types of research conducted in order to provide explanation to why people like playing with the slot machines. The conclusion is that the noteworthy design of the slot machines seem to exploit the bugs of the human brain. Here are the 3 phenomena occurring inside our heads during play: Machine Zone, Responding to randomness, Dealing with anxiety.

Machine Zone:

One interesting finding is that people do not have to think while playing, and many players go into a hypnotic state called ‘machine zone’. The players lose themselves in the machine as if medidating, and they desensitise their bodies by repetitive physical activity (Perry, 2012). Machine zone is thought to be similar to the flow state of the mind. It simulates the flow state which many artists explain that they enter. The flow is described as a place of deep concentration that feels natural, and where work is produced smoothly (Perry, 2012). This is the same flow state that the gamers experience, while playing a well- designed game with finely-balanced difficulty. Slot machine players mention “numbness” or “escape” and also “getting lost in the machine” while telling about how they feel during the interaction (Perry, 2012).

Responding to randomness:

Another fascinating finding of slot machine research is that the game generates bewilderment and enigma on the players because of its completely random nature. The game do not require any previously learned information nor any physical skills. Win or loose states occurring based on chance cause a confusion in our brain, because the fact is, the brain doesn't know how to process randomness (Gruetze, 2012). Dr. David Forrest, a clinical professor of psychiatry at Columbia University, explains that when the brain is exposed to a random experience, it categorises it with the other inexplicable phenomena, such as the random laws of the universe, which are thought to exceed the comprehension capability of the human brain. Notions as such are predicated to faith, mystic beliefs and godlike figures (Gruetze, 2012).

B.F. Skinner, a famous behavioural scientist conducted an experiment with pigeons to explain the brain vs. randomness phenomena. The pigeons would receive food at random intervals, unknowing where it comes from. After a while, the pigeons developed superstitions, and started believing that their own behaviour effected the food’s arrival. They would repeat certain movements hoping to get more food (Gruetze, 2012). Dr. Forrest indicates that this is akin to how the slot players behave, and explains that the brain handles random content by projecting a pattern on to it (Gruetze, 2012). Projection of pattern has a calming effect on the mind, similar to saying prayers (Gruetze, 2012).

Dealing with anxiety:

Life is full off problems. Players utilise the slot machines for getting away from any type of worry or burden in their daily lives, such as social anxiety, family and relationship problems, monetary issues, feeling of guilt, loneliness or existential crisis. The machines offer the players a break from real-life (Kurtz, 1991).

The amusement machines are generally outside the house. Yet even though there are people around, machine play can still be a very solitary activity. The machines supply players secure shells and something to do, so that they can hang out in a social setting alone and still feel comfortable. They can spend time in society without interacting with other people and trying to engage in small-talk (Robb, 2013).

MIT anthropologist Natasha Dow Schüll (2014) says: "The fact that people are being drawn to individual machine consoles rather than high- volatility, intense social games tells us a lot about the risk and volatility that people feel in the world, in their lives..." According to her findings, people are looking for games which provide them sense of control and predictability. This idea might sound contradicting, since many consider slot machine play as gambling, and they assume that the players are in for the thrill caused by releasing dopamine through risk-taking. As a matter of fact slot machines assure security to their players (Robb, 2013). In theory, the players have control over how much money to put in a machine, how much to bet in each spin and choosing when to end the play. There are no social pressures, there is only a machine to interact with. The slot play provide a safe cycle, in which the player cannot possibly make any severe mistakes. Plus, he is persistently rewarded with the random hits of feedback. The player practically enters a delightful zone where no worry exists.

Techniques Used In Design

So far, the text has covered how a slot machine operates and the mental effects of slot gameplay. This section will cover how these mental effects are engineered, by presenting the design techniques that a slot incorporates.


Humans are sensitive creatures, which means, we are responsive to stimuli. Our bodies have receptors for detecting the different kind of information in our environment such as light, sound and touch (Wikipedia, n.d.). A modern slot machine with video screens wouldn’t need the spinning to show the player whether he won or lost. The reels only spin to provide stimuli for the sake of gaming experience. If a player presses the spin button or pulls the lever, he will watch the reels spinning for several seconds on the screen before seeing the resulting combination. Actually the computer has already chosen the combination and determined what it is going to display, right at the point when the player pressed the button (Bourie, 2009). Not only it is exiting to watch and wait thorough the spin, but there are two other important factors why a slot does not display the result right away. These are: the timing of spins and the motion it dictates on the player.

The machine is spun 15 or 16 times per minute, which agrees with the ideal breathing rhythm of a mindfulness exercise such as meditation (Gruetze, 2012). The player’s breathing is synced with the spins without realisation during play. The product design tend to “put players in a prayerful state” (Gruetze, 2012).

The typical motion of reels has a significant effect too, as Dr. Forrest of Columbia University (Gruetze, 2012) declares:

"The reels descend. It's a very powerful thing. They force eyes to do a little up-and-down dance. The eye movement mimics a number of things that are important to us -- like submission, hypnotic obedience and also awe." Whenever a player is rewarded a bonus round, the design - the feedback of psychedelic colours, lights and sounds - leads him to look upwards toward the ceiling, his gaze reaching to the heavens. It is a relative experience for the brain when we enter one of those religious buildings with high ceilings, and look up to see the art painted above (Gruetze, 2012).

The makers of the slot machines also take in to account the effect of vivacious lights, high- definition graphics and pop culture themes while designing. These factors keep players visually satisfied, and when merged with audiovisual feedback and reward mechanisms they contribute to re-playability (Gruetze, 2012). In respect to the increasing popularity of slots over the years, variety of machines were created. Featuring of brand-new themes, well recognised movies and TV shows, and animated visual content served to keep the products up-to-date, and attract potential enthusiasts (Wikipedia, n.d.).

False win:

The slot machines are very good at telling white lies. They trick the players in to feeling that they are winning while they are actually loosing. Lets say a player puts in 20 £, which translates in to 100 units of machine credit. Playing a game costs 10 credits. The player pushes the button once, spending 10 credits. As soon as the spinning reels stop, the machine shoots cheerful, festive sound and light effects, and then tells the player that he just won 5 credits. The aftermath is that the machine has just taken his 1 £. Even though the player can calculate and see the real result immediately, he does not get upset and terminate the play. A division just occurred in his mind, because the machine responded as if he won. It did not feel like loosing while receiving such a response. In false win, the positive reinforcement hides the negativity of the situation, and deceives the mind (Stross, 2013).


As mentioned above in the text, human brain is fond of cycles and patterns. Contrary to popular belief, we enjoy monotony as long as we experience some surprises along the way. The slot machine provides a continuous play (Robb, 2013). The solitary nature of the console experience also supports this attribute. The player attention is not divided between multiple features, as it does in social play such as card and board games. The player do not have to pause the play to chat with others, discuss rules, wait for other player or the game to set up (Robb, 2013). The game is intentionally built in such manner to keep the player in loop.

The rhythm of the loop cause the body to be less perceptive by going in to the flow state (Machine Zone).The players do not feel the habitual psychological distress or bodily alerts such as hunger and thirst as much as they normally do when they are out of zone, thus they are less likely to stop playing (Perry, 2012).


If a slot player thinks that he nearly missed of a jackpot, he is terribly confused because there cannot be a real near-miss in a game based on pure luck. However the significant point is, this experience will most probably encourage the player to play more (Reid, 1986).

This is what actually happens in a ‘nearly missed jackpot’: The machine knows that the spin is a looser, and then it shows the player two of the symbols from a three-symbol winning combination (jackpot) right on the payline, and the third symbol needed for winning appears to be just above or below the payline, giving an illusion to the player that he almost won (Bourie, 2009). However this feeling of his has no base in reality since the probability of winning the next game remains constant, due to the RNG inside the machine (Bourie, 2009).

In skill based games occurrence of near-miss represents a positive outcome indicating that success is within reach (Reid, 1986). In games based on luck such as slot the near-miss has no effect over the future outcomes, though interestingly it might still effect the player’s behaviour. Even if he is well informed on how the machine operates, near miss can raise hopes and lead to superstitious behaviour. Studies show that people described the feelings after a near-miss in games based on luck as both “frustrating and encouraging”, and they also mentioned that they would like to “try harder” (Reid, 1986). As R. L. Reid from University of Exeter (1986, p.33) explains:

The conception of randomness of outcome is difficult to grasp and misconceptions are common. In everyday thinking "luck" is often regarded as a variable that can have different values at different times. A near miss can be taken as a sign that "luck" has changed value. What statisticians have to say about chance is not easy for most people to understand and when understood may not be fully accepted as a description of the real world.

In addition to causing misconceptions, a near miss can also supply a bit of the victory buzz, and lead the player to imagine another possible result which is better than what is on hand. This may generate feeling of disappointment, and regret can emerge as a way of resentment. In order to be freed of regret, the player may repeat behaviour and keep on playing (Reid, 1986).

Studying slot play helps designers to penetrate into the secrets of gaming experience. Slot, being a game of pure chance, combines short-term feedback loops with dazzling stimuli. The meditative effect of manipulating a slot machine leads the player to go into the hypnotic flow state. Slot games offer an easy and pleasurable zone, and they do not demand much investment. The realities of the world can be exhausting to bear all day everyday. In exchange for a small amount of money, the slot play provides a short break from life. Acknowledgement of the slot design will shed light on the social media applications and casual games, which seem to be the recent substitutes of the slot that people cannot get enough of.


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Floyd, M. & Chen, S., 2012. Study finds slot machine players don’t fit stereotype. Oregon State University News and Research Communications. Available at: nov/study-finds-slot-machine-players-don%E2%80%99t-fit-stereotype [Accessed December 20, 2017].

Gruetze, M. (2012). Psychiatrist explains why people are attracted to slot machines. [online] TribLIVE. Available at: [Accessed 18 Dec. 2017].

Kurtz, B., 1991. Slot Machines and Coin-op Games: A Collector's Guide to One-Armed Bandits and Amusement Machines.

Perry, S. (2012). Did You Know These 7 Surprises about Slots?. [online] Psychology Today. Available at: about-slots [Accessed 18 Dec. 2017].

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Robb, A. (2013). Why Are Slot Machines So Addictive?. [online] New Republic. Available at: https:// [Accessed 20 Dec. 2017].

Schüll, N. (2014). Addiction by Design: Machine Gambling in Las Vegas. Princeton University Press.

Stross, R. (2013). How Slot Machines Raise Our Hopes, Even When We’re Losing. [online] Available at: even-when-were-losing.html [Accessed 30 Dec. 2017].

Wikipedia, the free encyclopedia. (n.d.). Slot machine. [online] Available at: Slot_machine [Accessed 28 Dec. 2017].

Wikipedia, the free encyclopedia. (n.d.). Stimulus (physiology). [online] Available at: https:// [Accessed 29 Dec. 2017].

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