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Slots characteristics and slot players’ behavior

Slots are in present days the most popular casino games and also the games with the highest potential of becoming addictive. From an ethical commercial perspective, what distinguishes them from the other casino games is non-transparency, as the inner design of the slots machines is not publicly available information. From the 2000s, problem gambling researchers investigated from a statistical and psychological perspective the relationships between the slots structural characteristics and the slot players’ behavior. An influential study from 2009 carried out a double analysis on the retrieved inner design on some slot machines and the actual play of these games and revealed how the slots design fuels classical misconceptions, fallacies, and myths about slots, which for players are risk factors of developing a problematic gambling bahavior.

Exposed PAR Sheets available for research

A PAR sheet (Probability Accounting Report) is the “blueprint” of a slot machine. It contains the information regarding the conception of that game, namely the parametric configuration – symbols and their numbers, the symbol weighting of the reels, and symbol arrangement. This mathematical design of a slot game identifies the game and allows the calculation of all its statistical indicators – probabilities of hitting the prizes, RTP, and volatility.

The reasons why the slots producers keep their PAR sheet secrets are still unclear (and unjustified) and raise ethical issues from both a commercial and humanitarian standpoint.

The PAR Sheets can be retrieved only through legal intervention or by persistent request for research purposes.

Experts and researchers had in a very few instances the chance to study retrieved PAR sheets. The industry trade magazine Slot Tech Magazine published between 2001 and 2004 a some PAR sheets, which got the attention of problem gambling researchers.

Computer scientist Kevin Harrigan and psychologist Mike Dixon, from the University of Waterloo (Canada), obtained the PAR Sheets for slot machine games in use in Ontario throug the Freedom of Information and Protection of Privacy Act (FIPPA), which they analyzed in their influential research published in 2009. This research was based on the thesis that understanding the popularity and addictiveness of slot machines requires investigating what potential effects the slot machine’s characteristics have on the player.

The PAR Sheets retrieved through FIPPA refelected the inner design of one or more versions of the following slot games: Double Diamond Deluxe, The Phantom of the Opera, Lucky Larry’s Lobstermania, and Money Storm.

The content of a PAR Sheet for both experts and players

With their research, Harringan and Dixon also shared and explained the content of the PAR Sheets they analyzed, which turned to be useful information for both experts and slot players. Players may find insights from the core of a slot machine, learning how it actually works; this knowledge may stimulate their critical thinking about the outcomes and bahavior of these machines. Thus, the main terms associated with slots characteristics are defined and exemplified in their paper, for instance:

– ‘Symbols per reel’, denoting the number of instances of each symbol on each reel, information called the weighting of the reels. Multiplying these numbers on each reel yields the total number of possible combinations of stops (hits).

– ‘Payback %’, denoting the payback percentage (RTP), as the ratio between the total hits of the winning combinations and the total number of hits.

– ‘Hit frequency’, denoting the average percentage of times that the player will win something. It is expressed for each winning combination as the ratio between the actual hits and total hits (standing for the probability of that prize), then as a total.

– ‘Plays per jackpot’, denoting the average number of spins before a jackpot is won.

– ‘Plays per bonus’, denoting the average number of spins before bonus mode is entered.

– ‘VI’, abbreviation for ‘volatility index’, an idication of how much the game’s payback percentage will vary for a given number of spins.

For mechanical slot games using virtual reels, the PAR Sheet shows the weighting of the virtual reels and how these reels are mapped onto the physical 22-stop mechanical reels. Such machines function as follows: At each spin, the RNG chooses a number between 1 and the number of stops of each virtual reel (for instance, from 1 to 72). Following the mapping, the machine comands the physical reel to stop at the corresponding stop. This means that the probability of a combination of stops on the physical reel is not the same for all combinations, as it is on the virtual reel.

Observations from actual play

The two researchers made a double analysis: In parralel to their analysis of the retrieved PAR Sheets, they visited a casino for playing about 60 hours and for watching others playing those slot games. The goals were to observe several structural characteristics in play and how they reflect the way that slot machines actually bahave, focusing on the bonus mode, and to observe structural characteristics that are not contained in the PAR Sheets, like speed of play, stop buttons, and ‘hand-pays’.

In regard to speed of play, they found that the player can spin the traditional mechanical reel slot machines about once in 6 seconds (10 spins per minute or 600 spins per hour). The player can spin the video slot games about once every 3 seconds (1,200 spins per hour).

The hand-pay is a procedure applied to some machines when a win is higher than a certain amount (for example, $125 for Lobstermania). It causes the machine freezing, for an attendand to come, pay the player in cash, and then adjust the machine to resume normal play. The two researchers onserved over 20 hand-pays and estimated that it takes 5 minutes in average from the time the screen freezes until the normal play is resumed. The player usually fills that time with social interaction with other players.

Near-miss techniques in the slots design

Three of the games studied create a form of near-miss with a technique called ‘asymmetric reels’. When the reels are weighted such that there are several instances of a high-paying symbol on one line, it is frequently in non-winning combinations. For example, in Lobstermania, the number of lobster symbols on each reel is 2-5-6-0-0 and the occurrence of lobster symbols on reels 1, 2, and 3 in a line initiates a bonus. The player sees the lobster symbols 2.5 and 3 times respectively more frequent on reels 2 and 3 than on reel 1. Weighting reel 1 with a low number of lobster symbols (yet necessary for the bonus) increases the frequency of the near misses.

Two of the games studied used a technique for creating near misses as failures looking close to a win, called clustering. This type of near misses are created by manipulating the symbol weighting and arrangement of the virtual reels, such that a high-paying symbol appears on the payline on some reels (but not all) and just above or just below the payline on the other reels.

Another form of near miss is the situation in which the win is less than the wager, applying to multiline slots. For example, if the player wagers $0.05 on each of the 15 paylines and wins $0.45 overall, the rsult is a loss of $0.30 on the spin, although the machine indicates that it is a win. The computer analysis revealed that when wagering on all 15 paylines, the player wins in 33.52% of the spins on average, but 60.73% of these wins are less than the wager, so they are actually wins disguised as losses.

Hit frequency in multilines with scatters

Although PAR Sheets are supposed to provide exact information about the mathematical design of a slot game, the way this information is displayed may be itself misleading. An example of such a situation is the hit frequency in multi-line games with scatters.

In the standard layout and content of a PAR sheet, the parametric configuration of the game is displayed for one payline only; it is like treating each payline as a separate game.

The hit frequency – the percentage of time that a machine will give any payout – reflected in the PAR Sheets accurately reflects this definition for a single-line game. It is not the case with multi-line games with scatter wins. The explanation is that, when a player has more than one win on the same spin, that adds one to the number of hits in the hit frequency for each winning line, but it adds one only that counts in the percentage defining hit frequency.

A computer simulation for all possible outcomes and for each potential number of lines wagered in a version of Lobstermania, showed that the hit frequency, as defined, varies from 5.25% for one payline to 33.52% for 15 paylines. If there were no scatters and the 15 paylines were independent to each other, a player wagering on all 15 paylines with a 5.25% hit frequency would expect to win on 55.5% of the spins. The difference from the results of the computer simulation is due to two factors: Scatters are counted once per spin regardless the number of paylines wagered and the paylines are not independent to each other.

Implications for problem gambling

In behavioral psychology, the view has been crystallized that gambling behavior can be explained by using the principles of reinforcement, in particular the reinforcement schedules forming the patterns of wins and losses, and the long-term profit or loss is almost irrelevant in accounting for the effectiveness of this schedule.

In addition, a number of pathways may account for problematic gambling, and all players, regardless of their pathway, go through common processes, including classical and operant conditioning.

In slot machine play, pushing the spin button (as the operant conditioning) is intermittently reinforced by using a random-ration reinforcement schedule  and one of the consequences of winning is that player becomes aroused. Then this arousal response is involved in classical conditioning, while the proximal cues in the environment (lights, sounds, etc.) become conditioned stimuli.

The authors of the presented study considered how the various strructural characteristics of slot machines, which were revealed by the analysis of the PAR Sheets and their field observations, might impact arousal, classical and operant conditioning, and reinforcement schedules.

• Not all wins have the same status

Slot machines produce characteristic sights and sounds that accompany wins and the wide majority of these wins are low in amount. Nevertheless, the sounds and sights serve as sensory cues that differentiates in the player’s mind winning from losing spins. However, some of the small wins are actually losses, either at the current spin (as we explained for  the multi-line slots with scatters) or overall, taking into account previous losses.

For example, players on Lobstermania can wager up to 25 cents per line on up to 15 lines per spin. For those playing the maximum, this means $3.75 per spin in average and 66.48% of their spins will result in losses, but 33.52% of the time, the lights and sounds will indicate a win. Moreover, on 60.73% of these wins, the amont received will be less than the amount wagered.

• Hand-pay wins

It was found in other studies that, when a spin results in a relatively big win, the player tends not to spin again right away, but to pause. Such pauses may give the player enough time to think of the pleasure associate dwith the win, which adds to the arrousal.

The hand-pay – ocurring when a relatively large amount is won – assumes an imposed pause, which is supposed to legthen that post-reinforcement pause and maximize the rewarding value of the win.

The analysis revealed that for those players who continuously make the maximum wager, the frequency with which they experience a hand-pay is quite high – A player on a version of Lobstermania spinning the machine until exhausing an $100 bankroll has a  probability of 89% of experiencing a hand-pay.

Bonus mode

Near misses

Studies in problem gambling have advanced the thesis that near misses are interpreted by problem gamblers as a form of win in which the player is not constantly losing but constantly nearly winning.

The analysis of the discussed study revealed how assymetric reels and clustering techniques increases the frequency of the near misses, by the very manipulation of game’s parametric configuration. If the near-miss misinterpretation thesis is correct, than players experience rewarding arousal to the near misses. As a consequence, problem gamblers would receive rewarding arousal on more spins than would non-problem gamblers.

Such effects render of course the “artificial” (engineered by design manipulation) near misses the most critical risk factor associated with the relationship between slots structural characteristics and slot players’ behavior.

Final thoughts

The analyses of the PAR Sheets have implications for research, but also for policy and clinical interventions in problem gambling.

The information provided in PAR Sheets, as detailed information about the design of slot games, and frequency of wins, loses, and near misses, is therefore crucial for any congnitive-informative intervention in the zone of either prevention or treatment of problematic gambling at slots.

Many of the effects that the slot game design directly creates for the slot players are considered as risk factors in problem gambling, and hence the design itself and its non-transparency also raise ethical and legal questions.

References:

Blaszczynski, A., & Nower, L. (2002). A pathways model of problem and pathological gambling. Addiction, Vol. 97, 487-499.

Coventry, K.R., & Hudson, J. (2001). Gender differences, physiological arousal and the role of winning in fruit machine gamblers. Addiction, Vol. 96, 871-879.

Griffiths, M. (1993). Fruit machine gambling: The importance of structural characteristics. Behavioral Science, Vol. 9, 101-120.

Harrigan, K.A. (2008). Slot machine structural characteristics: Creating near misses using high symbol award ratios. International Journal of Mental Health and Addiction, Vol. 6, 353-368.

Harrigan, K.A. (2009). Slot machines: Pursuing responsible gaming practices for virtual reels and near misses. International Journal of Mental Health and Addiction, 7(1), 68-83.

Harrigan, K. A., & Dixon, M. (2009). PAR Sheets, probabilities, and slot machine play Implications for problem and nonproblem gambling. Journal of Gambling Issues, Vol. 23, 81–110.

Turner, N., & Horbay, R. (2004). How do slot machines and other electronic gambling machines really work? Journal of Gambling Issues, Vol. 11.