The role of auditory features within slot-themed social casino games and online
slot machine games
Department of Music, The University of Sheffield, Sheffield, United Kingdom.
Sally M. Gainsbury
Centre for Gambling Education & Research, Southern Cross University, Australia
Bramley, S. & Gainsbury, S. (in press). The role of auditory features within slot-
themed social casino games and online slot machine games. Journal of Gambling
Studies. DOI: 10.1007/s10899-014-9506-x
Abstract Over the last few years playing social casino games has become a
popular entertainment activity. Social casino games are offered via social media
platforms and mobile apps and resemble gambling activities. However, social casino
games are not classified as gambling as they can be played for free, outcomes may not
be determined by chance, and players receive no monetary payouts. Social casino
games appear to be somewhat similar to online gambling activities in terms of their
visual and auditory features, but to date little research has investigated the cross over
between these games. This study examines the auditory features of slot-themed social
casino games and online slot machine games using a case study design. An example
of each game type was played on three separate occasions during which, the auditory
features (i.e, music, speech, sound effects, and the absence of sound) within the
games were logged. The online slot-themed game was played in demo mode. This is
the first study to provide a qualitative account of the role of auditory features within a
slot-themed social casino game and an online slot machine game. Our results found
many similarities between how sound is utilised within the two games. Therefore the
sounds within these games may serve functions including: setting the scene for
gaming, creating an image, demarcating space, interacting with visual features,
prompting players to act, communicating achievements to players, providing
reinforcement, heightening player emotions and the gaming experience. As a result
this may reduce the ability of players to make a clear distinction between these two
activities, which may facilitate migration between games.
New technology and media is increasingly used for entertainment purposes and many
traditional offline forms of entertainment are now widely used online. Video games
and gambling activities have traditionally been distinct activities used by different
consumer groups, particularly since gambling is typically restricted as an adult
activity. Gambling requires individuals to pay to play and individuals are given the
opportunity to receive a predetermined monetary return or prize that is in part decided
by chance (Gainsbury, Hing, Delfabbro & King, 2014). In contrast, gaming may
require individuals to pay to play but games do not offer players the opportunity to
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 2
receive a monetary prize. Both gaming and gambling are now available online and
through social media sites making them highly accessible, increasingly similar and in
some cases linked. Social casino games are offered through social networking sites,
and mobile applications (apps) and simulate gambling activities (Gainsbury, Hing et
al., 2014). In addition to being visually similar, these social casino games appear to
use comparable auditory features to online gambling games. Within this study we
seek to understand whether the auditory features of social casino games and online
gambling differ, and the roles sound and music play within these types of games.
Social casino games are an extremely popular online activity, estimated to be
played by 173 million monthly players in 2012 (Morgan Stanley, 2012). This activity
has achieved substantial growth over the past few years as indicated by gross
revenues reaching US$1.98 billion in 2013, a 52% increase year on year (Krejcik,
2014). Social casino games offer users the opportunity to play simulated gambling
activities including slots, poker, roulette, blackjack, bingo, and sports wagering.
Social casino games are free to play, and do not pay out monetary prizes, and
outcomes may not be determined by chance, as such they are not classified as
gambling activities (Gainsbury, Hing et al. 2014). However, despite these differences,
social casino games have many similarities with gambling activities, and particularly
online gambling, which is now also available on social networking platforms and
mobile apps (King, Delfabbro & Griffiths, 2010a). Social casino game players can
purchase virtual credits using real money to access features, upgrades or bonuses.
The success of social casino games in generating revenue has resulted in the games
being offered as standalone games and as a marketing tool to encourage users to
migrate to gambling activities, including Internet gambling (Gainsbury, Hing et al.,
2014). Despite the impressive revenue as free-play games, social casino games
represent a fraction of the size of the Internet gambling market (Morgan Stanley,
The apparent similarities between social casino games and gambling users has
resulted in partnerships with and direct purchases of social casino game companies by
gambling companies (Gainsbury, Hing et al., 2014). Although the underlying game
mechanics may differ, the games can be visually very similar and the extent to which
consumers are aware of the differences between social casino games and online
gambling is not well understood. Because they are not regulated, social casino games
are available to children, games can have varied payout rates to entice continued play
with elevated wins, and encourage users to share the games with their online
networks. It is possible that players may not understand the differences between social
casino games and online gambling and migrate to gambling in the hopes of
experiencing similarly high levels of wins and monetary payouts (Rose, 2014). A
survey of 2,010 gamblers found that 13% played social casino games and these
gamblers were most likely to be younger, use Internet gambling and have high levels
of engagement with gambling (Gainsbury, Russell, & Hing 2014). This study
demonstrated that there is a cross over in those who play social casino games and
online gambling. Regulators in several international jurisdictions, including
Australia, the UK and Belgium have considered social casino games and whether they
represent an extension of online gambling or pose significant potential risks,
including for children and adolescents. Research is needed to compare the
characteristics of social casino games with those of online gambling to determine the
extent to which these games offer different player experiences.
Auditory features are important structural characteristics which may initiate,
reinforce and maintain gambling behaviour, and are incorporated into the design of
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 3
video games (Collins, 2008), gambling environments (Bramley, Dibben & Rowe,
2013) and electronic gambling machines (EGMs, Griffiths & Parke, 2005;
Livingstone et al., 2008). The auditory features associated with gambling include
music, sound effects, and vocal cues emitted by gaming equipment (Husain et al.,
2013). Gambling-operator selected recorded background music or live music can
create atmosphere and demarcate space within gambling environments (Bramley et
al., 2013; Griffiths & Parke, 2005). Background music is considered by some
machine gamblers to create an appropriate atmosphere for gambling (Husain et al.,
2013). Furthermore, sounds heard during play are considered to be appealing and
promote feelings of comfort and relaxation (Husain et al., 2013). The functions of
music within gambling machines include portraying the quality of the machine, aiding
gamblers to become familiar with the machine, creating an identity for the machine,
and signifying winning (Griffiths & Parke, 2005).
Sounds are emitted by EGMs in a number of instances. These include when
they are not being played in order to advertise the machine, notifying individuals
when they win or lose, and during bonus features. In a laboratory study, 24 regular
gamblers rated machines as more exciting during play and preferred to play on
machines when sounds were heard compared to when sounds were muted (Delfabbro,
Falzon & Ingram, 2005). However, sound did not actually influence play duration or
number of plays, whereas playing machines set at the maximum level of screen
brightness, led to longer gambling sessions (Delfabbro et al., 2005). This is consistent
with other studies of adults and adolescents (Dixon, Harrigan et al. 2013; Griffiths,
1990) suggesting that auditory cues may be a factor which gamblers consider when
deciding which game to play and may maintain gambling behaviour because sound is
a preferred feature of the machines.
There is evidence that sounds can influence gamblers’ perceptions of events
within a gambling session and their subsequent behaviour. Dixon and Harrigan et al.
(2013) found that sound emitted from a simulated slot machine played within a
laboratory situation led participants to overestimate the number of wins they had
experienced. In another study Dixon and Collins et al. (2013) found that sounds led
participants to miscategorise losses disguised as wins
(LDWs) as wins when they
were paired with winning sights and sounds. However, when LDWs were
accompanied by a “negative sound” most participants were able to categorise these
accurately (i.e. as losses) (Dixon, Collins et al., 2013). The study demonstrates that
players can use sound as a tool to determine their success during gambling sessions
(Dixon, Collins et al., 2013). During land-based slot machine play Husain et al.
(2013) found that players listened to the sounds emitted from their machine and
machines played by others in the same gambling environment. Such sounds assisted
gamblers to re-engage with the machine if they had become distracted (Husain et al.,
2013). Additionally, specific music and sound effects were played during bonus
features - machines emitted more noises as players progressed towards the jackpot
and players perceived the auditory features to add to the excitement of playing
(Husain et al., 2013). Sounds emitted from other machines in the environment were
considered to maintain gambling behaviour as players spent more money, changed the
game that they were playing and experienced negative feelings because other players
were winning (Husain et al., 2013).
Losses disguised as wins refer to the event in which a small win occurs, but this is less than the bet
made. The win is celebrated by the game, despite the player actually losing money (Harrigan et al.,
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 4
Researchers have found that gambling and video game playing share some
structural characteristics. For example sound can be emitted by video games, with
some video game players considering its presence to be enjoyable and important to
the playing experience (King, Delfabbro & Griffiths, 2011). Audio within video
games may facilitate immersion (Collins, 2008). Immersion, dissociation and
escapism are associated with gambling and video games, and may motivate some
individuals to participate in these activities (GfK NOP Social Research, 2009;
Ledgerwood & Petry, 2006; Wood, Griffiths, Chappell & Davies, 2004). Playing
video games or gambling can lead individuals to experience dissociative states which
involve losing track of time or being in a trance-like state (Wood et al., 2004). Losing
track of time can impact video game players both positively (e.g., facilitating
relaxation) and negatively (e.g., feeling guilty about wasting time) (Wood, Griffiths &
Parke, 2007). For some individuals, spending long periods of time gambling can led
them to experience gambling-related harm (Gainsbury & Blaszcyznski, 2012).
Similarly to gaming machines, video games employ speech, music and sound
effects to structure a game, attract a player’s attention, focus players towards a certain
aspect, and interact with the visual aspects of the game (Collins, 2008). Sounds
played in response to a player’s action is classified as a “player-generated event”
(Collins, 2013: 32) and its purpose may be to acknowledge actions performed by
players so that when actions are repeated, either that sound or a similar one is heard.
The sound played by the video game itself is classified as a “game-generated event”
and is initiated by the game’s algorithms, but may or may not require a response from
a player (Collins, 2013). Although music and sound effects may feature in social
casino games and online gambling, it is important to note that the auditory features do
not have to be heard by the player in order for a game to be played. Furthermore in
some Internet-based gaming and gambling activities players can alter the volume of
the sound or turn it off completely as preferred (Collins, 2008). In summary, the
sounds and music incorporated within the design of slot-themed social casino games
and online slots may potentially help gamblers to decide which game or gambling
activity to play, influence cognitive processes, and induce affective responses (Dixon,
Harrigan et al., 2013; Delfabbro et al., 2005; Griffiths & Parke, 2005; Husain et al.,
In this study we examine the convergence of auditory features by comparing
the sound present within slot-themed social casino games with sounds emitted by slot
machines available via online gambling websites. The study will improve knowledge
about the role of auditory features within these games. This is an exploratory study
using a case study design and therefore no specific hypothesises are offered regarding
the utilisation of auditory features within slot-themed social casino games and online
Materials and Method
Selection of games for analysis
A case study approach was adopted for this study and therefore an example of each
game was chosen for analysis. The game chosen to represent a slot-themed social
casino game was available via Zynga. Zynga is one of the largest and most successful
social casino gaming companies with around 10% market share. Hit it Rich! Casino
Slots is a popular game with 3.2 million monthly active players and 470,000 daily
active players in December 2013 (Krejcik, 2014). “Hit it Rich!”, available on
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 5
Facebook and launched as an iOS app in December 2013, offers 25 different slot
machine social casino games (Figure 1). The specific game analysed for this study
was “Cupid’s Kiss” accessed via the Hit it Rich! Application (Figure 2). “Cupid’s
Kiss” is a slot-themed social casino game with 5 reels and 40 paylines. Additionally it
offers arrow wilds and super symbol free spins to players.
The game “Thunderstruck II” was chosen as the game to represent an online
slot machine (Figure 3). “Thunderstruck II” was accessed via www.roxypalace.com
online casino website and played in demo mode meaning that the game was not
played for money. “Thunderstruck II” is a 5 reel pokie which offers 243 winning
combinations. The online casino website offers players the opportunity to play casino
games for free in the “practice play” mode. In the “Help” section of the online casino
website it stated that the games in “practice play” mode used exactly the same random
number generator as the one used within real money play, therefore odds of winning
were the same as those during real money play (Roxy Palace Casino, n.d.). The
games were chosen because their content was similar in that they did not feature film
or video clips.
Fig. 1 Screenshot of the lobby area of the application - “Hit it Rich!”
Fig. 2 Screenshot of the slot-themed social casino game - “Cupid’s Kiss”
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 6
Fig. 3 Screenshot of the online slot machine game - “Thunderstruck II”
To analyse the features of the games both the slot-themed social casino game and the
online slot machine game were played on three occasions, over five days at different
times by the first author. The first author is a musician, has received extensive
musical training and has completed a Music Degree. Therefore the first author is
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 7
qualified to assess and analyse the auditory features. Therefore no participants were
included in this study, however the study was completed in accordance with ethical
protocols. Playing the games on a number of occasions ensured a representative of
sounds within the games was achieved.
Each game was played until the bonus features were activated. The bonus
features were randomly activated by each game. The games were accessed via an
AppleTM laptop computer, which ran the OS X 10.8.5 operating system. Bonus
features were activated after 65, 31 and 166 spins for the online slot machine game
and after 145, 191 and 41 spins for the slot-themed social casino game. Session times
were on average 9 minutes and 58 seconds for the online slot machine game and 14
minutes and 17 seconds for the slot-themed social casino game. During play a log
was kept of the auditory features heard. Specific records were made for the music,
sound effects, speech, and absence of sound to differentiate between the different
types of auditory features heard. The play session was divided into four sections -
Pre-play, Within Session play, Achievement and Bonus Features. The Pre-play stage
of the play section refers to the point from when either the application or the website
opens to when a game was chosen to be played. Within Session play refers to the
time from when the game has loaded and during normal play (not including Bonus
Features of the game). Achievement relates to the ways in which players are
rewarded during game play. Bonus Features are when the game deviates from normal
play (Husain et al., 2013).
This section describes the music, sound effects, speech, and absence of sound heard
during game play. A summary of the auditory features utilised within the online slot
machine game and the slot-themed social casino game is presented in Table 1.
Table 1: Summary of the audio utilised within the slot-themed social casino game and the online slot
machine game by stage of game play
Stage of game
Slot-themed Social Casino Game
Online Slot Machine
- “Hit it Rich!” vocalised once the
application had loaded.
- Unique instrumental background
music (tempo = 123bpm) heard with
sound effects in the lobby area.
- Sound effects accompanied player
actions including browsing the “friend
zone” and hovering over in-application
- Sound effects based on the sound of
coins heard when viewing information
relating to purchasing coins and players’
“High Roller Status”.
- Duration of sound effects varied
according to “High Roller Status” points
total – longer for more points and vice
- No audio present.
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 8
- Unique instrumental background
music and sound effects heard in the
“High Limit Room” (jazz genre, tempo
= 115bpm) and “Tournaments” (rock
genre, tempo = 115bpm).
- Name of the “Tournaments” area
vocalised upon opening.
- Motif (short musical phrase) in the
style of a rock genre played to confirm
player’s choice of slot-themed social
- Instrumental background music heard
after the game had loaded, composed in
triple (Waltz) time, tempo =160bpm.
- Sound effects accompanied player
actions including hovering and clicking
onto in-game options.
- Sound effects higher in pitch heard
when increasing stake and vice versa
- Instrumental background music
developed when the “spin” button was
- Instrumental background music heard after
the game had loaded and played throughout,
composed in common time (walking or
marching beat), film music genre, tempo =
- Sound effects based on the game’s theme
were heard intermittently.
- Audio did not accompany players hovering
over the in-game features.
- Sound effects accompanied clicking onto
“view pays”, “increase” “decrease” credits,
“coins”, “bet max”, “spin”, “option”,
“bank”, “stats” and “regular” buttons.
- Sound effects accompanied reels
spinning and when reels came to a halt.
- Sound effects accompanied reels spinning
and when reels came to a halt.
- Sound effects accompanied bonus
symbols, if more than one bonus symbol
appeared specific sound effects were
heard incorporating speech, the audio
was higher in pitch and volume.
- No audio heard when waiting for the
player to press “spin”.
- Sound effects accompanied bonus symbols,
if more than one bonus symbol appeared
specific sound effects were heard together
with a visual informatics to inform players
that three or more bonus symbols were
needed to activate the bonus feature.
- Sound effects such as cheers and
whistles heard upon accessing the bonus
- Speech, music and sound effects used
to announce wins.
- Unique background music
accompanied game play, same tempo to
background music heard during within
session stage of game play .
- Novel background music played to
announce to players they had reached the
bonus features (tempo = 108bpm) featured
- Sound effects accompanied players actions
including hovering over the bonus options.
- Sound effects heard to confirm the player’s
choice of bonus feature.
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 9
- Novel music and sound effects heard
when players experienced “big wins”.
- Sound effects heard during Pre-play
were played at the end of the bonus
features when players were given the
opportunity to engage in social
- Audio ceased when the Bonus
Features had concluded.
- Unique background music accompanied
game play, rock genre, variation of the
background music used in the Within
Session stage of game play (tempo =
- Sound effects based on those heard during
the Achievement stage of game play were
played to announce wins.
- The removal of winning symbols was
accompanied by a sound effect.
- The background music that accompanied
within session stage of game play was heard
again to signal the end of the Bonus
- Wins signified by sound effects based
on the sound of coins or the
combination of music and speech.
- Duration of sound effects increased or
decreased depending on the size of
- Wins and LDWs were not
differentiated by the use of specific
- Losses were not signified by a either a
change in audio or the removal of any
- Music and sound effects signified wins.
- Musical motifs (short musical phrases)
were heard during “big wins” and “five of a
- Wins and LDWs were not differentiated by
the use of specific audio.
- Losses were not signified by a either a
change in audio or the removal of any audio.
Social casino game – “Cupid’s Kiss”
Upon opening the application “Hit it Rich!”, players entered the lobby area, where
sound was first heard. The name of the application was vocalised and a specifically
composed piece of instrumental background music was present which featured
realistic sound effects (i.e. sound which you might expect to hear in a casino, for
example, talking, cheers, coin sounds and reels spinning). The background music was
distinctive and its tempo was approximately 123 beats per minute (bpm). Bpm was
measured by counting the number of beats within a 15 second period and multiplying
the number by four to give the average bpm of the music. The background music was
a constant presence - it played whilst players browsed in-application features until the
player’s chosen game had loaded.
A sound effect was heard whilst players browsed the “friend zone”, an area of
the lobby which permitted players to connect with their Facebook friends. The same
sound effect was played when hovering over in-application options such as buying
coins, viewing their “High Roller Status”, customising the game in terms of turning
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 10
the sound off or on, changing the game to full-screen mode, sorting or browsing
games and entering either the “High Limit Room” or “Tournaments” areas.
Alternative sound effects were utilised to differentiate between other
functions, including visual messages appearing and areas relating to player rewards.
For example, the sound effect heard when hovering over the games differed to the
sound effect heard when the player clicked on the arrow to browse games. A unique
sound effect accompanied pop-up messages which appeared after players clicked to
view offers pertaining to buying coins at a promotional rate. Coins could be
purchased using real money to increase players’ spending power within “Hit it Rich!”.
When clicking onto the “Buy Coins” option sound effects were heard which
functioned as a fanfare. In addition, upon entering the area of “Hit it Rich!” where
players viewed information about their “High Roller Status” players heard unique
sound effects, based on the sound of coins. As the player’s points were displayed,
another sound effect, again based on the sound of coins was played but its duration
varied according to the number of points the player had achieved – longer for more
points and shorter for less points.
“Hit it Rich!” offered players the opportunity to play selected slot-themed
social casino games within a virtual “High Limit Room”. The machines available
within the “High Limit Room” were described by “Hit it Rich!” as “looser than our
regular slots, so you can bet more to win more!” (Chrystalyn, 2013). The lobby area
for the “High Limit Room” differed from the main lobby of “Hit it Rich!” in terms of
its background music. The background music was unique, its tempo was
approximately 115bpm and had not been heard prior to entering this area. The
background music featured synthesised instruments including a piano, drums and
cymbals. The music was composed within a jazz genre.
Additionally “Hit it Rich!” offered players the opportunity to enter in
tournaments. Clicking onto the “Enter Now” button led players into a different area
of “Hit it Rich!” and “Welcome to the Hit it Rich! Tournament” was announced by a
female voice. This area of the application was accompanied by unique background
music, which had not been heard previously. Its tempo was approximately 115bpm
and performed by synthesised electric guitars, drums, wind instruments and string
instruments. In addition, ascending and descending stylised coin sounds were heard.
The music was composed within a rock genre.
Within session play
During this stage of game play the slot-themed social casino game, “Cupid’s Kiss”,
was situated in the middle of two banners, one at the top and the other at the bottom
of the screen. The top banner contained the buttons which allowed players to return
to the lobby, view their “High Roller Status”, “Experience Level”, their remaining
coins, buy coins, turn the sound off and on, and play the game in full screen mode.
The bottom banner contained the “friend zone”. Hovering and clicking onto the
options contained within the two banners were accompanied by the same sound
effects as discussed previously within the pre-play section of the game. This sound
effect was also employed when hovering over game-related functions such as the
“pay table” button, adjusting bet size, using the “auto spin”, “spin” and “max bet”
Once the game had loaded, a specific piece of background music played and
repeated until the player pressed the “spin” button to the start the game. The tempo of
the background music was approximately 160bpm and was in triple (Waltz) time.
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 11
The sounds heard when players changed their stake had different pitches - increases to
bet size were acknowledged by the game playing a higher-pitched sound effect and
vice versa. In this instance pitch was associated with concepts of more and less in
relation to betting expenditure. Clicking the “max bet” button was acknowledged by
the game playing a variation of the sound effects heard when adjusting bet size.
Once the “spin” button was pressed, the background music developed and the
melody of the music was heard. The event frequency of the game could be adjusted
by players by pressing the “stop” button to halt the reels before the spin cycle had
completed. This action was accompanied by a unique sound effect. During a normal
spin cycle specific sound effects were heard as each reel came to a halt. The
appearance of certain symbols, for example the “bonus” symbol were accompanied
with unique sound effects that had a short attack. The sound effects were louder
compared to the background music. When more than one “bonus symbol” appeared
specific sound effects were played including voices which said “Oh” and rose in pitch
and volume, the reels also appeared to spin faster. If three “bonus symbols” appeared
then the bonus feature of the game was activated. No sound was emitted from the
game when waiting for the player to press spin during the normal game.
Players experienced two types of achievement when playing “Cupid’s Kiss”, firstly,
players were rewarded as a result of progressing through levels within “Hit it Rich!”.
Players’ progression was defined as their “experience level”, which increased each
time the player spun the reels, regardless of which slot-themed social casino game
they played via “Hit it Rich!”. Sounds were played when players progressed to the
next “experience level” within “Hit it Rich!” and also when they received bonuses
either as coins or a “High Roller Bonus”.
Secondly, players experienced wins and LDWs during game play. Wins
experienced during play were signified by specific sound effects based on the sound
of coins. The duration of the sound effects differed according to the amount of coins
that the player had won - a bigger win led to the sound effects being played for longer
and vice versa. Wins and LDWs were not differentiated by the use of specific sound.
Aside from coin sound effects accompanying wins, other wins were
accompanied by music and speech. Phrases were spoken by a female character which
referred to the theme of the game and the symbols which produced the win. Music
and speech were also sometimes heard simultaneously to announce when players had
experienced a win. In contrast losing was not signified by any additional sound being
heard or by sound being removed from the game.
The bonus feature of “Cupid’s Kiss” was where players received “free spins”,
meaning that players did not spend their coins to make bets. Access to the bonus
feature was announced by sound effects including cheers and whistles, which the
player may associate with being praised for their achievement. Speech in
combination with music and sound effects were used to inform the player that they
had won during the bonus feature. For example “kiss” sounds were utilised which
corresponded to the theme of the game and music was heard which had not previously
been heard during the game. During bonus features, combinations of music and
speech were heard to indicate when the player has received free spins and collected
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 12
their bonus winnings. “Big wins” experienced during the game were also notified by
unique music and sound effects.
Following the completion of a bonus feature, previously heard sound effects
(i.e. those heard when pop-up windows were displayed) were played. Players were
then offered the opportunity to engage in social aspects of the game such as by giving
gifts to their friends (e.g., “free spin bonus”) or by sharing their “big win”. In this
instance the sound effect played was a “game-generated event” and required a
response from the player – either to engage in social interaction or to refuse this
opportunity. No sound was emitted from the game after the bonus feature had
Online slot machine game – Thunderstruck II
The website that hosted the online slot machine game - “Thunderstruck II” did not
play any sound. Therefore player actions including browsing, hovering over options
and choosing a game to play, were performed in silence. Additionally, during the time
taken to load the online slot machine game no sound was heard. Therefore no
auditory features were present during the pre-play section of game play.
Within session play
An original piece of background music was played throughout game play. The tempo
of the background music was 80bpm and arguably it was composed in a film music
style. The music was somewhat understated, did not have a prominent melody and
was played at a lower volume compared to other music and sound effects employed
by the game. Sound effects, such as “thunderclaps”, were heard intermittently and
corresponded with the game’s theme. During within session play there were no
periods of silence, the background music played constantly, although it was at a lower
volume compared to the sound effects which featured more prominently and were
Hovering over the in-game features (i.e., “view pays”, “demo credits”,
“decrease” or “increase” credits, “bet max”, “spin”, "options”, “bank”, “stats”, and
“regular”) was not acknowledged by any sound effects or music. Clicking on the
“view pays” button was accompanied by a sound effect, as was clicking the
“increase” and “decrease” credits buttons, “coins” button, selecting the “bet max”
facility and “spin” buttons. The same sound effect was heard when pressing the “bet
max” or “spin” buttons. A different sound effect accompanied the clicking of
“option”, “bank”, “stats” and “regular” functions.
Once the “spin” button was pressed sound effects were heard whilst the reels
spun and when each reel stopped. Unique sound effects were played when the
“bonus” symbol appeared and when the remaining reels were spinning as if three or
more “bonus” symbols appeared then the bonus feature was activated. When two
“bonus” symbols appeared specific music was played and a visual informatic was
displayed to communicate to the player that three or more “bonus” symbols were
needed to activate the bonus feature.
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 13
During “Thunderstruck II” players received achievement in one form – the receipt of
credits in response to wins and LDWs. Wins were accompanied by specific music
and sound effects, which were higher in the mix and louder compared to the
background music. Motifs (short musical phrases) were heard during “big wins” and
when a win was a result of a player matching “five of a kind”. LDWs were also
acknowledged by sound effects and music. The duration of the sounds effects
differed according to how many credits were won - the sound effect repeated for a
longer or shorter duration according to the value of the win. The win sound was
arguably more interesting as it was based on arpeggios where the notes which form a
chord (the simultaneous sounding of two or more notes) are played separately one
after the other rather than at the same time.
Unique music was played to announce to the player that they had entered the bonus
features. Players chose one bonus feature from four options; and sound effects were
heard when the player hovered over the bonus options. For this study the first author
played the “Thor” bonus feature because it offered the highest number of free spins.
When the bonus feature was selected, a sound confirmed the player’s choice. During
the bonus feature specific music and sound effects were heard. The background
music which accompanied the bonus feature was different to the background music
played during the normal game in terms of its genre and the instruments used. This
music was composed in a rock-style genre and featured synthesised guitars.
Wins were announced by sound effects, similar to those used within the within
session stage of game play as they were created using arpeggios although played by a
different instrument. The winning symbols were then removed from the reels by the
game, an action that was accompanied by a sound effect. At the end of the bonus
features, the background music returned to original background music heard during
the within session stage of game play. This signalled the conclusion of the bonus
This exploratory study investigated the similarities between the auditory features of
slot-themed social casino games and online slot machines games. In these particular
examples of each game type sound featured in both games within all but one stage of
game play. Sound was absent from the pre-play stage of game play within the online
slot machine game, but was present during this stage of game play within the slot-
themed social casino game. In general sound tended to be used in similar ways
although there were some nuances which may shape play within these games.
Our analysis suggests that sound may aid players to differentiate between
these two games during the pre-play stage of game play. This is because sound was
absent within the pre-play stage of game play for the online slot machine game but
was present within this stage for the slot-themed social casino game. In the slot-
themed social casino game background music, speech, and realistic sound were
employed to announce to players that they had entered the application. Realistic
sound effects, together with realistic graphics and settings, are used within video
games and have been considered by video game players as a feature which can initiate
or maintain video game play (Wood et al., 2004). From this it may be that the
designers of slot-themed social casino games may use realistic sound effects to
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 14
heighten the enjoyment and social experience of social games. This is because social
games are designed to be shared with friends to maximise the entertainment
experience. The absence of sound within the pre-play section of the online slot
machine game may communicate to players that they had to navigate directly to
playing their chosen online slot machine game. From this the lack of sound may
initiate gambling for the online slot machine game, and sound’s presence may initiate
and set the scene for gaming within the slot-themed social casino game.
Additionally, the sound heard during the pre-play stage of the slot-themed
social casino game may communicate to players that they can participate in a range of
activities within “Hit it Rich!” and therefore sound demarcated space. The tempo and
genre of the music utilised within the slot-themed social casino game differed within
the pre-play stage as within the lobby area the music was composed in a style
suggestive of a game show theme tune and was faster in tempo. Fast tempo music
may have more arousal potential and cause more arousal in the listener (Berlyne,
1971). The music heard in the lobby area may lead players to feel excited and
stimulate the urge to play the games offered within “Hit it Rich!”. Within the “High
Limit Room” and “Tournament” areas, the music was slower in tempo but composed
within different musical genres – jazz for the “High Limit Room” and rock for the
“Tournament” areas. Within real life gambling contexts where slot machines are
located gambling-operators play different music genres in order to fit with customer
demographics (Bramley et al., 2013; Griffiths & Parke, 2005) and which slot
machines they played (Griffiths & Parke, 2005). The use of jazz in the “High Limit
Room”, where players spend more coins suggests that the designers of the slot-
themed social casino game may associate this genre of music with players exhibiting
different betting behaviour, as this particular music genre may prime thoughts
associated with sophistication.
Furthermore, sound may provide auditory feedback to players within the pre-
play stage of the slot-themed social casino game. This is because a number of player
actions were acknowledged by sound effects. Such actions included hovering,
clicking, and browsing using the mouse. ”Player-generated” sound was used and
provided auditory feedback to players (Collins, 2013). Moreover, during pre-play
slot-themed social casino game players first heard a sound effect classed as an
auditory icon (Gaver, 1986). The sound effect was based on a natural sound – that is,
the sound of coins. The use of auditory icons may have communicated to players the
importance of coins for “Hit it Rich!” and the slot-themed social casino game,
because coins were used as currency and was one way in which players received
rewards. The association between hearing coins and possibly receiving a reward was
arguably strengthened because when players perused information about their “High
Roller Status”, a “game-generated” event, in the form of coin sounds was heard.
Using sound effects in this manner is similar to how auditory features can be utilised
in video games as earning points or achieving a goal are often accompanied by
particular sounds (King et al., 2010b).
During the within session stage of game play both games utilised sound which
may help to create an image, guide individuals’ play, to influence players’ feelings
and to communicate to players. Original pieces of background music were used to
create an image by both games which is similar to how land-based slot machines
incorporate music into their design (Griffiths & Parke, 2005). However, there were
nuances between how the games employed sound at certain stages of within session
play. Firstly, in the slot-themed social casino game high pitched sounds were
associated with increasing expenditure and new musical information could be heard
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 15
whilst the reels were spinning. Such sounds may be considered by players as more
interesting and capture their attention. In contrast the background music heard when
playing the online slot machine game did not alter when the reels were spinning.
Secondly, the background music ceased when the slot-themed social casino game was
waiting for the player to press the “spin” button as a result the absence of sound may
communicate to the player that they were required to place another bet and may
therefore maintain play. This follows the suggestion by Griffiths and Parke (2005)
that gamblers who like the music played by land-based fruit machines may gamble
again because they are eager to hear the machine’s music. In contrast within the
online slot machine game the constant background music during within session play
may aid players’ focus and facilitate feelings of immersion. This corresponds with
some video games which use a constant soundscape to assist players’ focus when
playing in a distracting environment (Collins, 2008). From it could be that players
experience different levels of dissociation during play in relation to background’s
Within both games it appeared that the sound emitted by the games during the
within session stage of game play may be able to heighten players’ emotions. For
example when more than one “bonus” symbol appeared reels spun faster (slot-themed
social casino game), specific music and sound effects were played (both games) and a
visual informatic (online slot machine game) was displayed to inform players how
bonus features would be activated. Within the online slot machine game, high pitched
sounds were incorporated within these sound effects possibly to increase feelings of
tension and excitement about getting closer to reaching the bonus features. With
regards to land-based gambling, machine players have reported that listening to
machines could impact upon their expenditure and stimulate their urge to gamble
(Husain et al., 2013).
Achievements were signalled by sound within both games, however as the
slot-themed social casino game used two forms of achievement this may lead players
to receive rewards more frequently and on a more predictable basis compared to the
online slot machine game. Sound signified when players progressed to the next level
of the slot-themed social casino game, when they received bonuses or experienced
wins or LDWs. A variety of sounds were utilised to communicate achievement to
players including realistic sound effects, auditory icons (Gaver, 1986), speaking
characters and background music. Furthermore, as four auditory features were
sometimes heard simultaneously, these sound events may command more attention
from the player because they are more interesting and possibly more arousing. In
contrast online slot machines operate on random and variable ratio schedules
(Griffiths, 1999) therefore players may hear the sound which accompanies wins and
LDWs on a less predictable basis. However, given that in both games wins and
LDWs were not differentiated by the use of certain auditory stimuli, it may be that
players may overestimate wins as has previously been observed within laboratory
studies (Dixon et al., 2013b). In general both games appear to be similar to land-
based slot machines as achievements were announced by sound (Griffiths & Parke,
Arguably more interesting music and sound effects were played during bonus
features within both games. The games emitted sound previously unheard during
normal game play and given that these noises were novel it may be that such sounds
are perceived as exciting by players and capture their attention. Furthermore both
games used sounds based upon the theme of the game, for example “thunderclaps”
(online slot machine game) and “kiss” (slot-themed social casino game) sounds.
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 16
Land-based slot machines also use distinctive and memorable sound which may
maintain play (Griffiths & Parke, 2005). Within the slot-themed social casino game
speech, music and sound effects notified players that they had won and “big wins”
were notified by auditory icons (Gaver, 1986). The sound heard during bonus
features also demarcated space within both games and within the slot-themed social
casino game a “game-generated event” was utilised to prompt responses from players
(Collins, 2013). This instance shows how the slot-themed social casino game used
sound to inform players that they can become more involved with the game by
engaging in social interaction. Following bonus features the sound emitted by the
slot-themed social casino game ceased, once again signalling to players that this part
of the game had ended and calling players to act in order to play the game and hear
the sound again. This differs to the online slot machine game as the background
music heard during bonus features finished and the background music heard during
within session play returned. In both games the sound present changed at the end of
bonus features which may result in players’ arousal and excitement levels being
returned to the level prior to this stage of game play, following the hypothesis
proposed by Griffiths and Parke (2005) that the absence of background music during
land-based slot machine play may limit arousal.
This study has investigated the auditory features utilised within a slot-themed social
casino game and an online slot machine game. One of the most obvious differences
between the auditory features utilised within these particular examples games is at the
pre-play stage of game play. However during play the differences between audio’s
utilisation appear to be more slight and because they are less pronounced both games
may offer players comparable experiences. Nevertheless, the findings suggest that
there appears to be a degree of convergence between how both of these games utilise
auditory features, which may have implications for players.
The sound within these games may serve a range of functions including:
setting the scene for gaming, creating an image, demarcating space, interacting with
visual features of the games, prompting players to act, communicating achievements
to players, providing reinforcement and heightening player emotions. Sound may
enhance gaming and gambling experiences, and this may be particularly pertinent
during slot-themed social casino game play where there is no monetary incentive for
motivating play as players engage with this activity in order to connect with others
and be entertained. The similarities between these two games in terms of their
auditory features may facilitate the migration of more naive players from one game to
the other, however, this hypothesis is speculative and therefore ought to be tested
together with other factors (e.g., visual cues) which may play a role in player
A key strength of this research is that an in-depth case study of the auditory
features utilised within these specific examples of slot-themed social casino games
and online slot machines games has been conducted. This methodological approach
differs to previous studies, which have observed individuals playing land-based slot
machines and collected self-report responses from individuals (Husain et al., 2013;
Livingstone et al., 2008; GfK NOP Social Research, 2009; Griffiths & Parke, 2005).
The extent that such studies can provide insights into the auditory features utilised
within land-based slot machines can be limited because players do not necessarily
concentrate on auditory features and the scope of machines investigated may be
Bramley, S. & Gainsbury, S. (in press). Audio in social casino & online slot games 17
limited by player choice. In the present study a trained and experienced music
professional has conducted a detailed analysis of various in-game sections within slot-
themed social casino games and online slot machine games. In doing so we have
identified that within the auditory features present in slot-themed social casino games
and online slot machine games there are a number of musical characteristics (e.g.,
genre, instrumentation, pitch, realistic sounds, tempo, volume) utilised by the
designers, possibly with the aim of enhancing the gaming or gambling experience.
Future research could explore how players experience auditory features and whether
auditory features influence behaviour over repeated sessions of game play. This
follows previous research which found that EGM players perceived the audio emitted
from machines as enjoyable but they became dissatisfied with the audio over time
(Livingstone et al., 2008).
The findings of this study are somewhat limited in that they may not
generalise to other slot-themed social casino games and online slot machine games.
The methodology of this case study permits highly detailed findings about two games,
however this has the consequence of not producing results that are necessarily
representative of the wide number of games available. There are a vast number of
slot-themed social casino games and online slot machine games, which may vary in
terms of their design, their content, and functionality. Future studies may examine
other features utilised within slot-themed social casino games and online slot machine
games to investigate, for example, whether auditory and visual features interact. The
first author who was musically trained conducted the analysis of the auditory features
for this study. However future studies could recruit a second rater to improve
reliability. This study identified that the manner in which auditory features are
utilised in both online slot machines and slot-themed social casino games may
converge with land-based slot machines. Future studies could assess the role of sound
across these three activities. Lastly, our findings suggest the possibility that the sound
heard during slot-themed social casino games may be more reinforcing to players
because sound is heard more frequently because of the game’s mechanics. Further
research is required in order to determine to what extent auditory features reinforce,
shape and maintain play within slot-themed social casino games.
In conclusion, this study is the first to suggest that there are similarities
between the auditory features utilised within slot-themed social casino games and
online slot machine games. Auditory features may initiate, maintain or reinforce play,
and influence players’ interpretations of play (i.e., estimation of wins) in these types
of games. This study therefore acts as a starting point from which future research can
explore how players’ experience certain auditory features.
The manuscript does not contain clinical studies, participant or patient data.
Conflicts of interest:
The authors declare that they have no conflict of interest.
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