<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>Workshop
October</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>The Importance of Social Relations for Well-Being Change in Old Age - Do Game Preferences Change As Well?</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Maximilian Altmeyer</string-name>
          <email>maximilian.altmeyer@dfki.de</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Pascal Lessel</string-name>
          <email>pascal.lessel@dfki.de</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>DFKI GmbH</institution>
          ,
          <addr-line>Saarland Informatics Campus</addr-line>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2017</year>
      </pub-date>
      <volume>15</volume>
      <issue>2017</issue>
      <abstract>
        <p>Gamified systems may help older adults to remain physically, cognitively and socially active, which has positive effects on well-being. However, social aspects of psychological wellbeing change during life course, i.e., the importance of positive social relationships for well-being increases between young or middle aged persons and seniors. In this paper, we explore whether these changes are reflected in the game preferences of seniors aged 75 and older. We report findings of a semistructured interview and a preliminary player classification survey (N=18, mean age=84.61). We found indications that there are differences in game preferences and the perception of game elements that are related to the increased importance of social relationships for well-being in older ages.</p>
      </abstract>
      <kwd-group>
        <kwd>Author Keywords Older adults</kwd>
        <kwd>gamification</kwd>
        <kwd>game elements</kwd>
        <kwd>interviews</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>
        INTRODUCTION
Ryff [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ] proposes self-acceptance, positive relations with
others, autonomy, environmental mastery, purpose in life and
personal growth as essential features of psychological
wellbeing. It was shown that the perceived importance of these
features differs in old age [
        <xref ref-type="bibr" rid="ref12 ref14 ref15">12, 14, 15</xref>
        ]. One interesting finding
is that positive relations with others are found to be
significantly more important for well-being of seniors [
        <xref ref-type="bibr" rid="ref14 ref15">14, 15</xref>
        ]. Since
social game elements like competition or collaboration are
widely used in the domain of gamification [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ], where game
elements are used in non-game contexts [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ], we aim to
investigate in how far the perception of game elements or game
preferences changes in older ages.
      </p>
      <p>
        Investigating these game preferences is an important step
towards implementing gamified interventions supporting
positive psychological outcomes for seniors, to which we want
to contribute. Even though there are gamified systems
targeting seniors (e.g. [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]), most of those systems do not account
for age-related changes [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ] and are designed for a young
audience [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ]. However, there seems to be huge potential in
designing gamified systems supporting seniors: Besides the
fact that playing digital games was shown to be associated
with successful aging [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ], gamified systems may help older
adults to remain physically, cognitively and socially active [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ],
which has positive effects on health and well-being [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ].
In this paper, we report preliminary findings from a study with
the goal to find differences in the perception of game
preferences between a younger sample and seniors by comparing
the player type distribution of these samples. We moreover
report findings from semi-structured interviews with seniors,
in which we wanted to learn more about their game
experiences, what affects them positively when playing and whether
there are changes in these aspects throughout the life-span.
Our findings suggest that the increased importance of positive
social relationships is reflected in seniors’ game preferences.
We first provide background information about Marczewski’s
Gamification User Types Hexad Model [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. Afterwards, we
present related work and provide information about the study
design. Finally, we report and discuss results of our user study.
HEXAD MODEL
To assess participant’s player type, we used Marczewski’s
Gamification User Types Hexad Model [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ], consisting of
six player types that differ in the degree to which they are
driven by intrinsic or extrinsic factors (as defined by the
SelfDetermination Theory [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ]). Figure 1 illustrates the model and
which underlying motivational factors are relevant for each
user type. Below, we explain these user types based on [
        <xref ref-type="bibr" rid="ref19 ref8">8, 19</xref>
        ]
shortly and exemplary list an incomplete set of relevant game
elements based on findings from Tondello et al. [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ].
Philanthropists
Philanthropists are socially-minded players, who like to bear
responsibility, take care of and share knowledge with others.
They are altruistic and strive for goals having deeper meaning.
The most important motivational factor is purpose.
Game elements: Collecting and Trading, Gifting, Knowledge
Sharing, Administrative Roles
Socializers
Like Philanthropists, Socializers are socially-minded.
However, they are much more interested in interacting with others,
i.e. they like to create relationships and compete or cooperate.
The most important motivational factor is relatedness.
Game elements: Guilds or Teams, Social Networks, Social
Comparison, Social Competition, Social Discovery
Achievers
Achievers are satisfied when perceiving progress towards
clearly communicated goals. They also like to prove
themselves by completing challenges and diving into complex tasks.
The most important motivational factor is competence.
Free Spirits
Free Spirits are satisfied when they are able to express
themselves and have the opportunity to act without external control.
They seek for new, unconventional ways that can be explored.
The most important motivational factor is autonomy.
Game elements: Exploratory Tasks, Nonlinear Gameplay,
Easter Eggs, Unlockable Content, Learning
Players
Players are more out for their own benefits. They are driven
by the will to win and will do their best (independent of the
type of the activity) to earn rewards. The most important
motivational factor is getting rewards.
      </p>
    </sec>
    <sec id="sec-2">
      <title>Game elements: Points, Prizes, Leaderboards, Badges</title>
      <p>
        Disruptors
This player type is driven by compromising or disrupting
systems. Disruptors aim to trigger changes (positive or negative)
and test the boundaries of a system. The most important
motivational factor is triggering change.
RELATED WORK
Isselsteijn et al. [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] point out several opportunities and benefits
of designing digital games suited for seniors and outline that
there is a great need for research targeting the motivations
of them. This is supported by [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] pointing out chances and
considerations when using gamification for elderly people.
The authors emphasize the positive impact of gamified systems
encouraging physical activity, social relatedness or supporting
cognitive functioning on well-being of older adults.
Exploring the exercise motivations of older adults was the goal
of Kappen et al. [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. As a result of their findings, the authors
gleaned several design strategies for creating meaningful and
playful applications supporting physical activity. They
emphasize the need to consider the life stage without exploiting fears,
to explore ways to provide meaningful feedback to the users
as well as to support socialization around physical activity.
De Schutter [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ] reports findings from an online study in
which playing motives of elderly players were investigated.
Results indicate that a majority of them are solitary players
who like to play casual games. Concerning playing motives,
results revealed relatively low scores for nearly all motives
that were considered. The most popular motive was challenge
and the most important predictor for the time players invest in
playing games was shown to be social interaction.
These findings underline that social relationships are
particularly important in old age. In this paper, we aim to learn
more about whether this effect is transferable to the gaming
context by investigating senior’s attitudes towards social game
elements such as competition and collaboration.
      </p>
      <p>
        Nap et al. [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ] found that staying in touch with society and
escapism are motivators for seniors to play. There also was a
strong indication that participants prefer solitary over
multiplayer play, even though they appreciate socialization in
general. As potential reasons, the authors mention the increased
fear of failure seniors have as well as the unwillingness to be
dependent on other players and their availability. The fact that
participants value socialization relates well to the increased
importance of positive social relationships for well-being in
old age [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ]. Since participants disliked multiplayer games,
it seems like this change is not transferable to the gaming
domain at first glance. However, it might also be the case that the
fear of failure, which was reported by the authors as a
potential reason, only affects competitive games. Potentially, older
people are more inclined to collaboration than competition.
Analyzing this is part of our investigation.
      </p>
      <p>STUDY
The goal of the study was to explore how gamified systems
need to be designed to engage elderly people and to find
potential differences between seniors and a younger audience
that come from changes of relevant well-being aspects. To do
so, we investigate the following research questions:
RQ1: What are underlying factors that motivate older adults
to play games?
RQ2: Are game preferences of seniors related to the
increased importance of positive social relations?
Procedure and Method
We recruited participants from three nursing homes and
participants that are living on their own. To ensure that they do not
suffer from severe mental diseases and are able to
communicate without problems, we consulted the nursing management
(having access to disease-specific diagnosis of all residents),
that recommended participants. All participants agreed on
taking part in this study voluntarily. The study started with
a short questionnaire covering demographical data and
gaming frequency (both for analog as well as digital games) with
statements to be answered on 5-point Likert scales. A
semistructured interview followed to learn more about their gaming
experience, their motivation for playing games and potential
age-related changes in these aspects. The semi-structured
interviews were directly transcribed and were conducted in
faceto-face conversations alone with the participants in separate
rooms (in the nursing homes) or in participants’ apartments
(for those living on their own).</p>
      <p>
        After the interview, we determined the player type of
participants using Marczewski’s Hexad model [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ] to get further
insights about motivating factors for this age group and to
learn more about suitable game elements. To do so, we used
the German Hexad questionnaire of Korbas [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]. We
additionally classified a much younger sample using the same
questionnaire. This was done to investigate whether there are
age-related changes in game preferences. The survey consists
of 24 statements that are divided into four blocks consisting
of six elements, each representing one player type. We gave
the printed statements in four blocks one after another to the
participants to not overwhelm them (following the
recommendations from Smeddinck et al. [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]).
      </p>
      <p>The study took approximately one hour per participant and
was approved by the Ethical Review Board of the Faculty of
Mathematics and Computer Science at Saarland University.
During the study, drinks and snacks were provided to the
participants and breaks could be taken at any time.
Results
In total, 18 German participants took part in the study (10
female, 8 male – 13 living in nursing homes and 5 living on
their own) aged 84.61 years on average (Mdn=86, Min=75,
Max=93). Participants reported not to be familiar with
technology (M=1.5, SD=1.01, Mdn=1). However, they agreed
to being interested in accumulating more experience with
technology (M=3.83, SD=1.12, Mdn=4). In addition,
participants reported playing parlor games multiple times a week
(M=3.72, SD=0.80, Mdn=4) but never play video games
(M=1.39, SD=0.83, Mdn=1). One notable outlier is P15, who
reported being experienced with digital technology and is used
to playing digital games.</p>
      <sec id="sec-2-1">
        <title>Game Preferences and Reasons to Play (cf. RQ1)</title>
        <p>In the interview, participants reported to enjoy playing card
games like Rummy or Skip-Bo, followed by the lottery game
Bingo and board games like Ludo, Merels or Checkers. They
emphasized to enjoy and value the time spent playing: “After
playing games, I have the feeling of accomplishment, that time
was not wasted”1 (P3). Even those that do not play parlor
games regularly stated that this is mostly because they do not
have people to play with: “When my children were younger
we used to have a whole cupboard full of games and played
really a lot. Today I don’t have people to play with. [...] I
would definitely like to play more games again” (P16).
The questions about reasons for playing revealed a clear
picture: The main reason (mentioned by all participants), is
maintaining social contacts or socializing with others (“I often play
card games together with my roommate [...]. Most of the times
we play to spend time together and talk about our everyday
life” (P3)). They also reported seeing games as a starter for
conversations and that playing games provides an opportunity
to meet new people (“The Bingo evenings here helped me to
get in touch with other seniors living here” (P2)). We
furthermore found evidence that elderly people have fun watching
others play and use the occasion to get in touch with them
(reported by 5 participants): “Sometimes I just sit there and
watch others playing. It is fun to see their reactions and it
offers me the opportunity to talk to them” (P9).</p>
      </sec>
      <sec id="sec-2-2">
        <title>Social Aspects in Games (cf. RQ2)</title>
        <p>A vast majority of participants (16) reported not to be driven by
winning the game in first place but instead enjoy spending time
with others: “It is not about winning at all, it’s about spending
time together” (P3). While for 6 participants winning does not
matter at all, 10 participants stated that they also like to win,
but that is not most important: “The main reason [to play]
for me is to avoid being alone and enjoy time with others.
However, winning a game is also nice sometimes” (P10). We
also found that elderly people prefer collaborating in teams
instead of playing on their own: “We sometimes do teamwork
when playing Skip-Bo. [...] Winning as a team makes me much
happier than winning on my own” (P6). Since Skip-Bo is a
competitive game in which players normally play against each
other, this statement underlines the strive for collaboration
even more. In addition, the aspect of taking care of others
was mentioned by almost all participants (17). They indicated
to have a better experience when all players are satisfied: “It
is not too much about winning, it is more about ensuring
everybody has a good time” (P9).
15 participants reported that they were more inclined to
competition at younger ages: “When I was young I was a swimmer
and very ambitious [...]. Today I don’t want to compete against
others, those times are over” (P5). In addition, there is less
pressure to win a game and a more relaxed atmosphere during
play: “I think what has changed is that we don’t take things
too seriously when playing” (P4). A majority (14) of
participants stated that they value social contacts and communication
with others much more than in their younger years: “You get
more relaxed with increasing age and value different things. I
cherish social contacts or getting in touch with others much
more today” (P9), “Once you are old and live alone you
realize that having people around you is the most valuable thing
you can have” (P18).</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>1All statements were translated from German to English</title>
      <sec id="sec-3-1">
        <title>Player Types (cf. RQ1, RQ2)</title>
        <p>
          Considering the player types of seniors, the large majority
of them (83.3%) were classified as philanthropists, equally
followed by socializer (5.6%), player (5.6%), achiever (5.6%)
and no participants being classified as free spirits (see
Figure 2a). To investigate age-related changes in game
preferences, we compared this distribution to a much younger
sample consisting of 31 participants that were recruited from our
university (20 male, 11 female) having a mean age of 25.61
years (SD=4.64, Mdn=24). The player type distribution of
the younger sample was much more diverse than in the older
sample (supporting findings from Korbas [
          <xref ref-type="bibr" rid="ref6">6</xref>
          ] and from an
online survey using a different player type instrument2 both also
considering a younger sample, see Figure 2c). 29.41% of the
younger sample were classified as philanthropists, followed by
free spirits (20.59%), players (17.65%), achievers (17.65%)
and socializers (14.71%) (see Figure 2b).
        </p>
        <p>
          Discussion
Overall, results suggest that when conceptualizing gamified
interventions aiming for positive psychological outcomes among
seniors, changes in relevant aspects of well-being and the
specific needs of this audience should be considered.
We learned that socializing is a core motivator for seniors to
play. More specifically, we found that seniors play to
communicate and maintain social contacts and not to win the game
in first place. In addition, they considered taking care of and
collaborating with other players to be very important, as they
do not want to make other players feel sad. These findings
indicate that the importance of positive relations for well-being,
that increases with older age [
          <xref ref-type="bibr" rid="ref14 ref15">14,15</xref>
          ], also plays a major role in
the gaming context. We therefore suggest using collaborative
game elements over competitive ones (which is also reported
in an online study with 140,000 gamers3) and integrating
communication capabilities to support the need for social exchange
when aiming for positive psychological outcomes.
2https://gamified.uk/UserTypeTest2016/
user-type-test-results.php, last accessed September 15,
2017
3http://quanticfoundry.com/2016/02/10/gamer-generation/,
last accessed September 15, 2017
We moreover found indications that the importance of games
as catalyzer for social relationships increases in older ages and
that winning the game is not as important as it is in younger
ages. These changes are very transferable to the changes of
well-being aspects that were reported. The increased
importance of positive relationships relates well to the importance of
games to build social relationships, to the aspect of care-taking
and to the strive to ensure all players feel well. The changes are
also reflected in the distribution of player types in our sample
as a vast majority is classified as philanthropists, a
sociallyminded, altruistic player type that loves to share knowledge
and take care of others. Since socializers are motivated by
competition, this player type seems to be the most appropriate
one regarding the results we have from the interviews. The
altruism and care-taking aspect underline the requirement to
build positive relations with others even more.
        </p>
        <p>Given that the younger sample we considered showed a much
more heterogeneous player type distribution, it would be
interesting to investigate reasons for this as we cannot reliably
say whether people turn into philanthropists with increasing
age, whether the difference is attributable to the generation in
which participants were born or whether the instrument we
used to determine the player type is not suitable for older
populations. Given our current results, we think that the perception
of certain game aspects changes during life-span, as a majority
of participants explicitly stated that they were more ambitious
in games and that the aspect of social relationships in games
was reasonably lower when they were younger.</p>
        <p>Important to note is that the results are preliminary and should
be seen in this light as more studies with larger sample sizes
are needed ultimately draw conclusions. Moreover, the fact
that a huge majority of participants were recruited from
nursing homes might have an impact on their attitude towards
social aspects in games, additionally affecting the
generalizability. Nevertheless, we argue that the presented investigation
provides interesting insights into game preferences of seniors
and how changes in well-being aspects might be transferable
to the gaming domain that open up questions and directions
for discussion and future work such as considering reasons for
changes of game preferences in old age.</p>
        <p>
          CONCLUSION
Although there is huge potential in improving well-being
of older adults through gamified systems [
          <xref ref-type="bibr" rid="ref2">2</xref>
          ], these systems
mostly do not account for age-specific changes [
          <xref ref-type="bibr" rid="ref5">5</xref>
          ]. To
inform the design of such systems, we investigated attitudes
towards game aspects and changes of game preferences of
seniors. Results suggest that changes in well-being aspects are
reflected in the gaming context, i.e. we found that seniors value
communication and collaboration much more than winning
the game and strive to ensure every player enjoys the game
equally. These changes are supported by differences in the
player type distribution between seniors and a younger sample,
suggesting that game preferences change throughout the
lifespan. Thus, we conclude that these specific needs should be
considered when creating gamified interventions supporting
psychological well-being in old age.
        </p>
        <p>For future work, it would be interesting to investigate
reasons for the differences in the player type distribution and
to validate our findings with more participants in order to
derive guidelines supporting the design of gamified systems
encouraging well-being for seniors.</p>
      </sec>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <given-names>Sebastian</given-names>
            <surname>Deterding</surname>
          </string-name>
          and
          <string-name>
            <given-names>Dan</given-names>
            <surname>Dixon</surname>
          </string-name>
          .
          <year>2011</year>
          .
          <article-title>From Game Design Elements to Gamefulness: Defining "Gamification"</article-title>
          .
          <source>Proceedings of the 15th International Academic MindTrek Conference. ACM</source>
          ,
          <year>2011</year>
          . (
          <year>2011</year>
          ),
          <fpage>9</fpage>
          -
          <lpage>15</lpage>
          . DOI:http://dx.doi.org/10.1145/2181037.2181040
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          2.
          <string-name>
            <given-names>Kathrin</given-names>
            <surname>Maria</surname>
          </string-name>
          Gerling and
          <string-name>
            <given-names>Maic</given-names>
            <surname>Masuch</surname>
          </string-name>
          .
          <year>2011</year>
          .
          <article-title>Exploring the Potential of Gamification Among Frail Elderly Persons</article-title>
          .
          <source>Proceedings of the CHI 2011 Workshop Gamification</source>
          :
          <article-title>Using Game Design Elements in Non-Game Contexts (</article-title>
          <year>2011</year>
          ),
          <fpage>1</fpage>
          -
          <lpage>4</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          3.
          <string-name>
            <given-names>Wijnand</given-names>
            <surname>Ijsselsteijn</surname>
          </string-name>
          , Henk Herman Nap, Yvonne Kort, and
          <string-name>
            <given-names>Karolien</given-names>
            <surname>Poels</surname>
          </string-name>
          .
          <year>2007</year>
          .
          <article-title>Digital Game Design for Elderly Users</article-title>
          .
          <source>Proceedings of the 2007 conference on Future Play</source>
          (
          <year>2007</year>
          ),
          <fpage>17</fpage>
          -
          <lpage>22</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          4.
          <string-name>
            <surname>Dennis L Kappen</surname>
          </string-name>
          , Lennart E Nacke,
          <string-name>
            <surname>Kathrin M Gerling</surname>
            , and
            <given-names>Lia E</given-names>
          </string-name>
          <string-name>
            <surname>Tsotsos</surname>
          </string-name>
          .
          <year>2016</year>
          .
          <article-title>Design Strategies for Gamified Physical Activity Applications for Older Adults</article-title>
          .
          <source>Hawaii International Conference on System Sciences</source>
          (
          <year>2016</year>
          ),
          <fpage>1309</fpage>
          -
          <lpage>1318</lpage>
          . DOI: http://dx.doi.org/10.1109/HICSS.
          <year>2016</year>
          .166
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          5.
          <string-name>
            <given-names>Jonna</given-names>
            <surname>Koivisto</surname>
          </string-name>
          and
          <string-name>
            <given-names>Juho</given-names>
            <surname>Hamari</surname>
          </string-name>
          .
          <year>2014</year>
          .
          <article-title>Demographic Differences in Perceived Benefits From Gamification</article-title>
          .
          <source>Computers In Human Behavior</source>
          <volume>35</volume>
          (
          <year>2014</year>
          ),
          <fpage>179</fpage>
          -
          <lpage>188</lpage>
          . DOI: http://dx.doi.org/10.1016/j.chb.
          <year>2014</year>
          .
          <volume>03</volume>
          .007
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          6.
          <string-name>
            <given-names>Sebastian</given-names>
            <surname>Korbas</surname>
          </string-name>
          .
          <year>2015</year>
          .
          <article-title>Gamification User Types zur Unterstützung der Konzeption in der Softwareentwicklung</article-title>
          . Mensch und Computer 2015 - Workshopband (
          <year>2015</year>
          ),
          <fpage>367</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          7.
          <string-name>
            <surname>Bruce</surname>
            <given-names>W Lemon</given-names>
          </string-name>
          , Vern L Bengtson, and James A Peterson.
          <year>1972</year>
          .
          <article-title>An Exploration of the Activity Theory of Aging: Activity Types and Life Satisfaction among In-Movers to a Retirement Community</article-title>
          .
          <source>Journal of Gerontology 27</source>
          ,
          <issue>4</issue>
          (
          <year>1972</year>
          ),
          <fpage>511</fpage>
          -
          <lpage>523</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          8.
          <string-name>
            <given-names>Andrzej</given-names>
            <surname>Marczewski</surname>
          </string-name>
          .
          <year>2015</year>
          .
          <article-title>Even Ninja Monkeys Like to Play: Gamification, Game Thinking and Motivational Design</article-title>
          . CreateSpace Independent Publishing Platform.
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          9.
          <string-name>
            <given-names>Anne</given-names>
            <surname>Collins Mclaughlin</surname>
          </string-name>
          and
          <string-name>
            <given-names>Maribeth</given-names>
            <surname>Gandy</surname>
          </string-name>
          .
          <year>2013</year>
          .
          <article-title>Successful Aging Through Digital Games: Socioemotional Differences Between Older Adult Gamers</article-title>
          and
          <string-name>
            <surname>Non-Gamers</surname>
          </string-name>
          .
          <source>Computers In Human Behavior December</source>
          <year>2016</year>
          (
          <year>2013</year>
          ). DOI: http://dx.doi.org/10.1016/j.chb.
          <year>2013</year>
          .
          <volume>01</volume>
          .014
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          10.
          <string-name>
            <surname>Alberto</surname>
            <given-names>Mora</given-names>
          </string-name>
          , Carina González, Joan Arnedo-Moreno, and
          <string-name>
            <given-names>Alexis</given-names>
            <surname>Álvarez</surname>
          </string-name>
          .
          <year>2016</year>
          .
          <article-title>Gamification of cognitive training: a crowdsourcing-inspired approach for older adults</article-title>
          .
          <source>Proceedings of the XVII International Conference on Human Computer</source>
          Interaction - Interacción '
          <volume>16</volume>
          '
          <fpage>16</fpage>
          (
          <year>2016</year>
          ),
          <fpage>1</fpage>
          -
          <lpage>8</lpage>
          . DOI: http://dx.doi.org/10.1145/2998626.2998663
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          11.
          <string-name>
            <surname>H.H. Nap</surname>
            , Y.a.
            <given-names>W.</given-names>
            De Kort, and W.
          </string-name>
          <article-title>a</article-title>
          .
          <source>IJsselsteijn</source>
          .
          <year>2009</year>
          . Senior Gamers: Preferences,
          <source>Motivations and Needs. Gerontechnology 8</source>
          ,
          <issue>4</issue>
          (
          <year>2009</year>
          ),
          <fpage>247</fpage>
          -
          <lpage>262</lpage>
          . DOI: http://dx.doi.org/10.4017/gt.
          <year>2009</year>
          .
          <volume>08</volume>
          .04.003.00
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          12.
          <string-name>
            <surname>Gary</surname>
            <given-names>Reker</given-names>
          </string-name>
          , Edward Peacock, and
          <string-name>
            <given-names>Paul</given-names>
            <surname>Wong</surname>
          </string-name>
          .
          <year>1987</year>
          .
          <article-title>Meaning and Purpose in Life and Well-Being: A Life-SPan Perspective</article-title>
          .
          <source>Journal of Gerontology</source>
          (
          <year>1987</year>
          ),
          <fpage>44</fpage>
          -
          <lpage>49</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          13.
          <string-name>
            <surname>Richard M Ryan and Edward L Deci</surname>
          </string-name>
          .
          <year>2000</year>
          .
          <article-title>Self-Determination Theory and the Facilitation of Intrinsic Motivation, Social Development</article-title>
          , and
          <string-name>
            <surname>Well-Being</surname>
          </string-name>
          .
          <source>American Psychologist</source>
          <volume>55</volume>
          ,
          <issue>1</issue>
          (
          <year>2000</year>
          ),
          <fpage>68</fpage>
          -
          <lpage>78</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          14.
          <string-name>
            <given-names>Carol</given-names>
            <surname>Ryff</surname>
          </string-name>
          .
          <year>1989</year>
          .
          <article-title>Happiness is Everything, or Is It? Explorations on the Meaning of Psychological Well-Being</article-title>
          .
          <source>Journal of Personality and Social Psychology</source>
          (
          <year>1989</year>
          ),
          <fpage>1069</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          15.
          <string-name>
            <surname>Carol</surname>
            <given-names>D</given-names>
          </string-name>
          <string-name>
            <surname>Ryff and Corey Lee M Keyes</surname>
          </string-name>
          .
          <year>1995</year>
          .
          <article-title>The Structure of Psychological Well-Being Revisited</article-title>
          .
          <volume>69</volume>
          ,
          <issue>4</issue>
          (
          <year>1995</year>
          ),
          <fpage>719</fpage>
          -
          <lpage>727</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          16. Bob De Schutter.
          <year>2010</year>
          .
          <article-title>Never Too Old to Play: The Appeal of Digital Games to an Older Audience</article-title>
          .
          <source>Games and Culture</source>
          (
          <year>2010</year>
          ),
          <fpage>1</fpage>
          -
          <lpage>16</lpage>
          . DOI: http://dx.doi.org/10.1177/1555412010364978
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          17.
          <string-name>
            <given-names>Katie</given-names>
            <surname>Seaborn</surname>
          </string-name>
          and
          <string-name>
            <given-names>Deborah</given-names>
            <surname>Fels</surname>
          </string-name>
          .
          <year>2015</year>
          .
          <article-title>Gamification in Theory and Action: A survey</article-title>
          .
          <source>International Journal of Human-Computer Studies</source>
          <volume>74</volume>
          (
          <year>2015</year>
          ),
          <fpage>14</fpage>
          -
          <lpage>31</lpage>
          . DOI: http://dx.doi.org/10.1016/j.ijhcs.
          <year>2014</year>
          .
          <volume>09</volume>
          .006
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          18.
          <string-name>
            <given-names>Jan</given-names>
            <surname>Smeddinck</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M</given-names>
            <surname>Herrlich</surname>
          </string-name>
          , and
          <string-name>
            <given-names>M</given-names>
            <surname>Krause</surname>
          </string-name>
          .
          <year>2012</year>
          .
          <article-title>Did They Really Like the Game?-Challenges in Evaluating Exergames with Older Adults</article-title>
          .
          <source>CHI 2012 Workshop on Game User Research: Exploring Methodologies</source>
          (
          <year>2012</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          19.
          <string-name>
            <surname>Gustavo F Tondello</surname>
          </string-name>
          ,
          <string-name>
            <surname>Rina R Wehbe</surname>
            , Lisa Diamond, Marc Busch, Andrzej Marczewski, and
            <given-names>Lennart E</given-names>
          </string-name>
          <string-name>
            <surname>Nacke</surname>
          </string-name>
          .
          <year>2016</year>
          .
          <article-title>The Gamification User Types Hexad Scale The Gamification User Types Hexad Scale. The ACM SIGCHI Annual Symposium on Computer-Human Interaction in Play (</article-title>
          <year>2016</year>
          ). DOI: http://dx.doi.org/10.1145/2967934.2968082
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>