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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>What makes a trophy hunter? An empirical analysis of Reddit discussions</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Chien Lu</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Jaakko Peltonen</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Timo Nummenmaa</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Xiaozhou Li</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Zheying Zhang</string-name>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Tampere University</institution>
          ,
          <addr-line>Kalevantie 4, 33100 Tampere</addr-line>
          ,
          <country country="FI">Finland</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2020</year>
      </pub-date>
      <fpage>1</fpage>
      <lpage>3</lpage>
      <abstract>
        <p>In this paper, an empirical data-driven analysis of online discussions of meta-game reward systems is carried out. The data is collected from one of the biggest online discussion forums called Reddit and a text-mining technique called topic modeling is employed. Over 46000 discussion threads from the two most relevant subreddits /r/xboxachievements and /r/Trophies are analyzed and the results of topic modeling shows not only interesting topics but also the (dis)similarity between two text sources the temporal trends of topics. We have found that the volume of related discussions shows an ongoing trend. The topic model results have also revealed that some game genres are more prevalent than others and the (dis)similarities between text sources have been also discovered.</p>
      </abstract>
      <kwd-group>
        <kwd>trophy hunting</kwd>
        <kwd>Reddit</kwd>
        <kwd>topic modeling</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Introduction</title>
      <p>
        It has been noted that games can also be gamified [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ], which has attracted
researchers’ attention [
        <xref ref-type="bibr" rid="ref14 ref9">9,14</xref>
        ]. Early work on applying badge systems to non-game contexts
have also used game achievement systems as a source of inspiration [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]. One of the
gamification design implementations is a meta-game reward system, which awards
visual indicators for completion of tasks and acts as an overarching game in which
players obtain rewards through playing across different games [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ]. In game industries,
meta-game reward systems have been widely used such as badges (STEAM),
achievement points (Xbox) or trophies (PlayStation), etc. [
        <xref ref-type="bibr" rid="ref12 ref15 ref30">12, 15, 30</xref>
        ].
      </p>
      <p>
        Reddit, a major participatory culture platform [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ], wh has more than 138,000
active subreddits (each represents a focused sub-community) and more than 330 million
users. Due to the number of discussions, the text content has been a valuable resource
in various fields [
        <xref ref-type="bibr" rid="ref16 ref22">16, 22</xref>
        ]. There are two subreddits related to our interests:
/r/xboxachievements, a place to “show off achievements” has more than 3 thousand
users and /r/Trophies has more than 25 thousand “trophy hunters”. They both yield an
abundance of discussions that reflect the gamers or potential gamers’ perception.
However, despite containing valuable information, they have not been well explored.
      </p>
      <p>This work performs a large-scale data-driven analysis of gamers’ interests and
attitudes toward two reward systems with comprehensive data collection of discussion
threads in the above described two sources. We use topic modeling to
computationally extract themes of discussion from the huge corpus. How the prevalence of the
extracted themes varies over the two subreddits and over time are further estimated.</p>
      <p>The rest of the paper is structured as follows. Section 2 describes related work.
Section 3 describes data collection and text mining methods. Section 4 describes the
resulting extracted themes. Section 5 provides analysis and discussions. Conclusions,
limitations, and opportunities can be found in Section 6.
2</p>
    </sec>
    <sec id="sec-2">
      <title>Related work</title>
      <p>
        Cruz et al. [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] investigated meta-reward systems for Xbox and Playstation and how
they affect game players’ experience. They collected discussions from focus groups
of 36 console players and used Self-determination theory (SDT), Organismic
integration theory (OIT), Cognitive evaluation theory (CET) and Signaling theory (ST) as
the framework to analyze the discussions. SDT, OIT, CET disclose an individual’s
motivations [
        <xref ref-type="bibr" rid="ref26">26</xref>
        ] and ST provides a framework to understand how the information is
sent and interpreted when communicating [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]. Many studies shed light on importance
of game reward systems towards players’ enjoyment and motivation. Jakobsson,
based on study of the Xbox 360 achievement system, indicates it not only works as a
reward system but also as a multiplayer online game in which all Xbox players
participate compulsorily [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. Wang and Sun suggest players enjoy game rewards and react
to the motivation they provide while indicating that reward mechanisms foster
intrinsic motivation and give extrinsic rewards based on relevant psychological theories
[
        <xref ref-type="bibr" rid="ref27">27</xref>
        ]. By studying the reward system of World of Warcraft, Rapp emphasizes
importance of rewards in shaping player experiences but suggests to consider reward
designs carefully to “surpass the exclusive employment of extrinsic motivators in
gamification design” [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ]. Many studies obtained positive outcomes adopting design
similar to game reward systems in gamification and serious games [
        <xref ref-type="bibr" rid="ref20 ref8">8, 20</xref>
        ].
      </p>
      <p>
        One example of using empirical data is the work of Wells et al. [
        <xref ref-type="bibr" rid="ref28">28</xref>
        ] who analyzed
30,227 PlayStation user profiles to explore how factors including, PlayStation Plus
subscriptions, player regions, etc., influence earning achievements. Using data from
Steam, O'Neill indicates achievements may incentivize more playtime from players
who would have otherwise played less [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ]. Players' achievements data and data
mining methods are also used in analyzing their performance in serious games towards
enhancement of players' motivation and engagement [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]. Many studies have chosen
Reddit as their data source when researching users' opinions on various topics [
        <xref ref-type="bibr" rid="ref13 ref29">13,
29</xref>
        ]. We didn’t find works analyzing text of online discussion regarding meta-game
reward systems, perhaps due to difficulties when it comes to a large amount of data.
We tackle the issue by a computer-aided solution explained in Section 3.
      </p>
      <p>We aim to answer three research questions. RQ1. Is discussion of the meta-game
reward system an ongoing trend? RQ2. What kind of games are more mentioned
concerning meta-game reward systems? RQ3. What are similarities &amp; dissimilarities
of discussion between Xbox and PS about the meta-game reward system?
3</p>
    </sec>
    <sec id="sec-3">
      <title>Method</title>
      <p>Data Collection and Processing. Reddit threads from the two subreddits between
2014 and 2019 (until the 17th of October) were collected via the pushshift API1. The
text was lemmatized and stop words removed. Each submission with its comments
was aggregated as a document. We eliminated submissions without comments as they
did not evoke discussions. Documents with less than five words were filtered out after
processing. In total, we obtained 1384 documents from /r/xboxachievements and
45145 documents from /r/trophies, more details shown in Table 1.</p>
      <p>
        Text Mining. We used a text mining technique called topic modeling to analyze the
collected online discussions. It is a probabilistic model that represents each document
as a mixture of several latent topics. Each topic speaks for a specific semantic theme
within the data collection. The topics are not provided by a human expert but are
learned by an algorithm in a data-driven manner. Topic models such as Latent
Dirichlet Allocation [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] have been used in domains including game studies (e.g. [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]).
      </p>
      <p>
        The basic representations found by a topic model are: 1) The strength (prevalence)
of the latent topics; each topic has a prevalence in each document, represented as
proportions that sum to one, and can be summarized over different data subsets. 2)
The vocabulary of the topics, represented as a distribution over typical words in each
topic. In this work, a more advanced approach called Structural Topic Model (STM,
[
        <xref ref-type="bibr" rid="ref25">25</xref>
        ]) is employed. It is a topic model where the strength of topics within a document
can depend on document-level covariates, enabling us to model both text content of
the documents, and how they are affected by annotations. We take the document
source (subreddit) and submission time (initial time of the discussion series) as
document-level covariates. The two covariates are taken to model (dis)similarity between
two subreddits and the temporal dynamics. Compared to conducting topic modeling
in two sources separately (e.g. [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]), this provides an integrated solution via directly
treating the effect of the source as a learned parameter in the model.
      </p>
      <p>
        We use held-out likelihood as the criterion to decide the number of topics K, the
user-specified parameter of STM. For efficiency we first searched from K = 10 to 500
with an interval of 5; the best setting was K = 355. We investigated exhaustively from
K = 351 to 359 and K = 355 was still the best. We set up 10 initializing models with K
= 355; the model with best semantic coherence [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ] was adopted as the final model.
4
      </p>
    </sec>
    <sec id="sec-4">
      <title>Results</title>
      <p>tics of the top words and example documents of the topic (having high prevalence of
the topic). Topics whose top words prominently contained words for specific game
titles or characters were denoted as specific topics about those games; such topics
might concern multiple games, such as a game series, if often discussed together.
While separation of topics on specific games into genres cannot be made fully
conclusively, each topic was tagged with one or more genres. Non-game-specific topics
were labeled according to semantic themes they contained. Topics with no clear
semantic theme were labeled as linguistic topics that provide nuance to the Reddit
discussion but which are not a focus of our analysis. Note that each topic may weakly
contain other thematic content besides the main one marked as their label.</p>
      <p>The /r/Trophies subreddit introduced a bot ‘PSNTrophyBot’ in 2018 which
describes a game’s trophies, for example, “God of War has 37 trophies: 22 bronze, 8
silver, 6 gold, and platinum...”. The bot adds ‘I am a bot’ to the end of its posts; thus
topics where ‘bot’ was among the top words were considered related to bot activity
and are shown in the online full table but not focused on in later analysis. A selection
of found topics are in Tables 2 - 32. We discuss selected examples next.</p>
      <p>Game related topics. 105 of the 355 topics (30% of the topics) turned out to be
game-specific (see online full table). The most discussed game-specific topics were
about games PlayerUnknown’s Battlegrounds, the ‘Infamous’ series, point and click
adventure games from Telltale Games, the ‘Far Cry’ series, Uncharted the Lost
Legacy and Conan Exiles, the ‘Assassin’s Creed’ series, the Lego video games series, the
‘God of War’ series for Playstation portable, Demon’s Souls and Bloodborne, and
Rocket League and Teslagrad. We do not present their top words in Tables 2-3 as
they are game-specific: for example, the Telltale Games topic contained words like
‘walk’, ‘telltale’, ‘episode’, ‘dead’, ‘tale’, ‘batman’, ‘borderland’, and ‘season’
referencing games like ‘The Walking Dead’ and ‘Tales from the Borderlands’. However,
examples of game-specific time courses are shown in Fig. 1 to demonstrate the rise
and fall of a game’s popularity for trophy-hunting: PlayerUnknown’s Battlegrounds
(Plot (a), Fig.1) is slowly declining, whereas Grim Fandango and Day of the Tentacle
(Plot (b), Fig.1) have a strong Playstation peak in 2017. See the full set of plots for
other games: e.g. Tomb Raider has little change on Playstation but has a peak around
2016 on Xbox, and Uncharted a broad Playstation peak around 2017. The broader the
peaks, the more enduring the game and its reward mechanism are for trophy hunters;
the strongest ones can serve as examples for future design.</p>
      <p>2 Full table at shorturl.at/hrtH5, all time plots at shorturl.at/ t/uFGN.
Topic
Boss fights and weapon upgrades
Shooting and kills
Fan hopes for sequels
Purchasing modes and preordering
Getting trophies
Milestone
Frustration and perseverance
Enjoyment and motivation
Multiplayer gaming
Bugs in games
Memories and nostalgia
Attempting and memorizing
moves and routes</p>
      <p>Reward related topics include going for certain types of rewards, earning rewards,
reward difficulties, congratulates others, and discussing rewards themselves. Some
share feelings of accomplishment, topics Earning trophies and happiness,
Milestone, Enjoyment and motivation indicate pride and celebration. In Milestone, a
user stated: “...I’d share my 100% of this as I hit level 100 yesterday, the game is
consuming my life at the moment!”. Some topics imply the achievement difficulty
level, e.g. Easiness and achievability and Difficulty of getting trophies; topics like
Achieving trophies after long time and Dedication required from players imply
perseverance and commitment. In Easiness and achievability, a user stated: “...I just
kept at it until I got em. Otherwise, the trophies in both Pac-Man games are pretty
simple...”. Topics about feelings (Fun of playing) and fandom (Memories and
nostalgia indicate players’ memorable experiences of the games, and lifestyle (Time
allocation to playing, relationship) indicates players’ commitment to playing as part
of their life. Wastefulness and pointlessness expresses a feeling of time waste, and</p>
      <sec id="sec-4-1">
        <title>Frustration with difficulty and perseverance, Games becoming boring or stale,</title>
        <p>and Grinding and monotony indicate mixed feelings for the reward system. A user
stated in Wastefulness and pointlessness: “...played both games over 200 hours and
fully enjoyed them but can never waste time collecting pointless...”. Seek
information about a trophy reflects information sharing among users.</p>
        <p>Gameplay related topics. These topics indicate players hunting for trophies aim to
find information to excel and to be aware of the games’ problems and updates,
including gameplay experiences (Multiplayer gaming, Fighting moves: combos,
countering and blocking and Boss fights and weapon upgrades) and technical aspects
(Patches and glitches, Bugs in games, Saving and restoring progress, corruptions
and backups). Enjoyment and recommendation of entertainment and Fan hopes
for sequels link individual games to larger entertainment culture. Buying in packs
for discounts, Downloadable content and expansions and Purchasing modes and
pre-ordering indicate financial planning of trophy hunters.</p>
        <p>Temporal Dynamics. Trends of selected topics are in Fig 1. E.g. Grinding and
monotony on Playstation peaks in 2016 but is rising on Xbox in 2018-2019;
Deciding to try a platinum trophy peaks on Playstation in 2017. Dotted lines represent
95% confidence intervals; non-overlapping intervals of two curves suggest
significantly different prevalences. Some topics are Domain-specific. Game-specific topics</p>
      </sec>
      <sec id="sec-4-2">
        <title>PlayerUnknown’s BattleGrounds and the “Tomb Raider” series are more preva</title>
        <p>lent in /r/xboxachievements whereas Grim Fandango, Day of the Tentacle,
“Spider-Man” series and Uncharted The Lost Legacy, Conan Exiles are more
prevalent in /r/Trophies. Besides, topics Messaging and invites, Completion percentage,</p>
      </sec>
      <sec id="sec-4-3">
        <title>Requesting and appreciating help, are found to be more mentioned in</title>
        <p>/r/xboxachievements whereas Games becoming boring or stale, Grinding and
monotony, Time allocation to playing, Deciding to try a platinum trophy and
Congratulations are more mentioned in /r/Trophies. Attempting moves and routes has
an attention shift, as the trends have opposite directions in the two sources.
5</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Discussion</title>
      <p>As shown in Table 1, the data volume is drastically growing indicating growth of the
communities and impact of meta-game reward systems on gameplay and social
media, so we answer our RQ1: the trend is clearly ongoing.</p>
      <p>
        A sizable proportion of topics were game-specific indicating which games are most
discussed, answering RQ2. Action-adventure games were the most discussed genre
(topics with that genre tag had a total prevalence 0.069), followed by first-person
shooters (0.022), role-playing games (0.022) and platformers (0.020). The rest had a
prevalence of under 0.010. Discussions on multi-player games (e.g. PlayerUnknown’s
Battlegrounds) can be connected to the statement by Jakobsson [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ] that the reward
system can itself be a massive multiplayer online game. Topics such as Requesting
and appreciating help, Congratulations are related to the relatedness in SDT.
      </p>
      <p>The (dis)similarity of focus in the two subreddits is learned by STM and can be
evaluated from its parameters, answering RQ3. Topics that are more prevalent in
/r/xboxachivements such as Messaging and invites, Completion percentage and
Request, appreciate help are more related to pragmatic means of achieving scores.</p>
      <p>While /r/Trophies has a wider variety of discussions, from perceived emotions
(Games becoming boring or stale, Grinding and monotony and Congratulations)
to decision making (Time allocation to playing, Deciding whether to try a
platinum trophy and Difficulty of getting trophies, note that, although the last two topics
contain PlayStation-specific words such as “platinum” and “trophy”, other terms
(“decide”, “tricky”) can convey general semantic meanings so that they may also
appear in /r/xboxachievements threads). This could be due to that PlayStation has
different levels of rewards from Bronze to Platinum. This layered design enhances the
complexity and potentially enrichs the online discussions. The r/xboxachievements
subreddit is also smaller by comparison which means some of the discussion on Xbox
achievements has spread out more to other venues, such as r/xbox, a more general
discussion venue on Xbox related topics.</p>
    </sec>
    <sec id="sec-6">
      <title>Conclusions, limitations, and opportunities</title>
      <p>We presented a data-driven topic modeling study of player’s interests and attitudes to
reward systems based on two subreddit corpora. Our qualitative analysis of text
content was assisted by computational text mining. The results were both interesting on
their own and supported human interpretation and efficient analysis of a large amount
of text data. We found semantically meaningful topics on game series, trophy-hunting
techniques, appreciation of achievements, dissatisfaction with difficulty, grinding, and
time use, and their temporal fluctuation. Appreciation or frustration revealed by the
topics can help promote a similar appreciation and avoid frustration in future
gamification design. The topics provide an understanding of players’ attitudes and opinions
regarding gamification (i.e., badge and achievement systems) of games. The topics
show players commit game achievement-related behaviors, e.g., expressing
frustration, asking for help, appreciating help, and etc. via online forums. Benefits of such
behaviors towards continuous engagement in achievement pursuing and game playing
can be useful for other gamification applications.</p>
      <p>
        This work used only Reddit discussions; other large-volume venues include the
Playstation Forum and Xbox achievement discussion forum. This can lead to a bias as
most Reddit users are from the United States. More categorical analysis can be
conducted in future by combining data sources, e.g., Twitter, Steam Community, etc., or
comparing to other methods, e.g., Non-Negative Matrix Factorization (NMF) [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ].
      </p>
      <p>Deepened understanding of player behavior regarding game trophies and
achievements can facilitate the design of personalized gamification, and application of such
computational methods towards the understanding of player communities can enrich
game studies. We expect the computational approach will inspire similar studies,
especially in game studies. The discovered topics and temporal trends can further be
used to establish research questions or directions in related fields.</p>
    </sec>
    <sec id="sec-7">
      <title>Acknowledgments References</title>
      <p>The work was supported by Academy of Finland decisions 312395, 313748 and
327352.</p>
    </sec>
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