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  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>Nov</journal-title>
      </journal-title-group>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Preparing a Psychological Experiment on a Tactile Display</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Jan Bernoth</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Yves Wittstock</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Raphael Zender</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Tina Urbach</string-name>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Ulrike Lucke</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Department of Computer Science</institution>
          ,
          <addr-line>A.-Bebel-Str. 89, 14482 Potsdam</addr-line>
          ,
          <country country="DE">Germany</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>University of Potsdam</institution>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2014</year>
      </pub-date>
      <volume>16</volume>
      <issue>2014</issue>
      <abstract>
        <p>Seamless IT interfaces can provide sophisticated environments for experiments. We describe a setting from motivational psychology, targeting to identify the attitudes and strategies of Poker players by observing their individual cards and activities in a non-invasive way. A digitally supported game on a tactile table can help to simulate a typical casino atmosphere even in a lab environment, while necessary data can be directly gathered and stored for later processing. Starting from the requirements defined from psychologists, we describe selected design issues when deploying the Poker game to the tactile display. The paper concludes with findings collected in experiments and recommendations for further work.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;Decision making</kwd>
        <kwd>Poker</kwd>
        <kwd>Tactile interface</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>Permission to make digital or hard copies of part or all of this work for
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      <p>Copyright is held by the owner/author(s).
comparatively stable, that is their decisions are always affected by
the same variables (e.g., quality of own cards, betting behavior of
other players). Other aspects of the environment, like the many
influences that are present in typical scenarios of daily life or
work, can be rather neglected. In such a gaming context, it is
possible to study further determinants of decision making, such as
motivational processes or individuals’ attitudes. The current study
will investigate the interplay of achieving gains versus losses and
individuals’ self-regulation processes, that is how individuals
adapt their behavior and betting decisions to the course of their
play. This makes Poker games a valuable object of study, given
that the conditions are close enough to a common casino setting.
A table with a touch-sensitive display is a proper tool for such
experiments, since it combines the natural appearance and
handling of the game with the possibility to seamlessly measure
all required parameters.</p>
      <p>
        The article describes the design aspects of such experiments,
which were prepared in combined efforts from psychology and
computer science. This work is based on general design guidelines
for haptic interfaces [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] and games [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ], as well as on the concept
of immersion [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. Starting from the specific requirements defined
by the investigators from psychology, along with the framing
conditions of available tools and technologies, we analyzed the
current state of the art and derived our own approach for
designing the experimental setting. This is described in section 2.
The results of our work, with a focus on technical design issues,
are presented in section 3. First results of psychological
experiments are stated in section 4. The article concludes with
some findings from this projects as well as ideas for further work
in section 5.
      </p>
    </sec>
    <sec id="sec-2">
      <title>2. DESIGNING A TACTILE POKER GAME</title>
      <p>The central approach is to support a minimum invasive data
collection by the utilization of a table-sized computer with
interaction patterns that are mentally close to a traditional Poker
game. While the output of the Poker application is audio-visual,
the input of the players is tactile in order to achieve a naturalistic
handling.</p>
    </sec>
    <sec id="sec-3">
      <title>2.1 Identified Requirements</title>
      <p>Besides the main requirement to implement a highly realistic
Poker game, the following sub requirements have been formulated
to ensure valuable experiments:</p>
      <sec id="sec-3-1">
        <title>Support of 4-6 players</title>
      </sec>
      <sec id="sec-3-2">
        <title>Designated cards and chips area for each player</title>
      </sec>
      <sec id="sec-3-3">
        <title>Natural and undisturbed game flow Poker mode: Texas Hold’em (including common rules like rotating dealer, random cards, …)</title>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>2.2 Related Work</title>
      <p>The number of digital and even touch-based Poker games is high.
But, most of them do clearly falsify the flow of a traditional Poker
game. They create a considerable distance between players by
using separate devices or put a specific, non-natural technical
system into the foreground of the gaming environment. Thus, we
focused on Poker games that can be carried out on a table-sized,
touch-based computer to simulate the traditional Poker setting.
Thus, only the following two candidates have been identified to
be relevant for this project.</p>
      <p>
        The Poker surface system [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] has been developed as a
combination of a touch-based table component and a mobile
phone component. The table serves as central gaming area, while
the mobile device shows players their private cards and supports
several interaction gestures. The players may even play tricks
(manipulations) with their chips. In general, this software could
have been a very useful groundwork for our project.
Unfortunately, the code was not accessible for further work.
Moreover, the non-natural way to integrate mobile phones into the
game flow was another drawback of this system.
      </p>
      <p>Another solution for a touch-based table is the Surface 2.0
Multitouch Poker system that was developed in a student project
and published as Open Source1. The software is well-split into
two components: A table-site, open part and a mobile, private
part. Large parts of this solution could be re-used for our project.
However, user tests have revealed several discrepancies between
expected and occurring system behavior, i.e. Poker rules were not
adequately implemented, and some functions were buggy.
Therefore, several modifications have been made. Furthermore,
the software lacks ofs appropriate logging mechanisms for the
collection of the required experimental data. These have been
added.</p>
      <p>Both systems have been developed for the Microsoft PixelSense
platform (formerly: Surface), one of the most popular and
affordable multi-touch table computers. The same hardware will
be used in this project.</p>
    </sec>
    <sec id="sec-5">
      <title>2.3 Approach for Development</title>
      <p>
        As we decided to use the Micosoft PixelSense table computer, our
tactile Poker game benefits from the Surface 2.0 Multitouch Poker
software.
1 https://github.com/B3J4y/Poker
The chosen hardware is a Samsung SUR40, running the Microsoft
PixelSense platform [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. The table computer has a 1080p LCD
HD display with a screen diagonal of 40”. Per 8 pixels one optical
sensor recognizes objects on the display surface. Pre-defined
shapes are used to identify objects like fingers and optical
PixelSense tags. A powerful AMD Athlon II CPU as well as a
Radeon HD 6700M graphics board ensure smooth handling even
with this high resolution and touch recognition. The system is able
to simultaneously handle up to 52 fingers and other objects. The
PixelSense uses a modified Windows 7 operating system. Figure 1
depicts an empty gaming environment.
      </p>
      <p>The Surface 2.0 Multitouch Poker software for this hardware
already covers central game mechanics and comes with a pleasant
graphical design. However, some fundamental changes had to be
implemented to fulfill the defined requirements:
•
•
•
•
•</p>
      <p>No use of mobiles, to reduce the technical distraction as well
as the setup time to a minimum (just to the table computer)
Implementation of an alternative mechanism for private
areas/cards as we do not use mobiles
Implementation of appropriate logging mechanisms to collect
data about decision making
Correction and optimization of tactile interaction
mechanisms regarding to initial Poker tests with the
unmodified software
Implementation of helpful gaming instructions for Poker
beginners
The following section explains and illustrates the resulting Poker
software in more detail.</p>
    </sec>
    <sec id="sec-6">
      <title>3. THE TACTILE POKER ENVIRONMENT</title>
      <p>One of the central requirements was the creation of a mostly
realistic Poker setting. IT tools like the PixelSense table are used
to log the player actions. Though, players should feel and act as in
a traditional casino atmosphere. The following design issues of
the resulting Poker@PixelSense have been considered due to this
philosophy, based on the previously defined requirements.</p>
    </sec>
    <sec id="sec-7">
      <title>3.1 Special Design Issues on a Tactile Display</title>
      <p>The implementation of our Poker@PixelSense system was
designed for up to six players. This number of players is typical
for Poker games. Moreover, this is the maximum of players to be
conveniently placed around the table (size: 108 cm × 70 cm).
To ensure consistent experimental settings over multiple game
runs, the software performs all tasks of a dealer. This includes:
Thus, the experiment investigator’s tasks are limited to the setup
of a game:
After the start of a game round, the table presents the Poker
environment as depicted in Figure 3. The number of player areas
depends on the number of registered players. Four to six players
are a valuable number. The player area is labeled by the player’s
name or – as for anonymous data collection – just by a number.
Furthermore, the current player amounts are given for a simple
orientation.</p>
      <sec id="sec-7-1">
        <title>Dealing and uncovering of cards</title>
      </sec>
      <sec id="sec-7-2">
        <title>Automated collection of blinds</title>
      </sec>
      <sec id="sec-7-3">
        <title>Monitoring of correct bet and call amounts</title>
      </sec>
      <sec id="sec-7-4">
        <title>Interpretation of cards</title>
      </sec>
      <sec id="sec-7-5">
        <title>Proclamation of the winner(s)</title>
      </sec>
      <sec id="sec-7-6">
        <title>Distribution of the pot</title>
      </sec>
      <sec id="sec-7-7">
        <title>Placing of players at the table</title>
      </sec>
      <sec id="sec-7-8">
        <title>Registration of players’ names in the software</title>
      </sec>
      <sec id="sec-7-9">
        <title>Initial sizing of players’ stacks</title>
      </sec>
      <sec id="sec-7-10">
        <title>Initial sizing of the blind Start of the game</title>
        <p>•
•
•
•
•
•
•
•
•
•
•
Each player area includes multiple elements. One of the most
important elements is the personal set of two virtual gaming cards.
In general, the use of physical Poker cards instead of digital cards
would increase the immersion of the Poker setting. Unfortunately,
this is not feasible because of the low recognition resolution of the
hardware and other recognition restrictions (e.g. red color is not
recognized due to the light spectrum used by the optical sensors).
Thus, a pure digital game without physical artefacts has been
developed.</p>
        <p>The players can look “under” their cards by using their fingers to
slightly move the deck image to one side. As Figure 4 illustrates,
the players in our experiments mostly used their other hand to
hide the exposed cards – as known from a traditional Poker game.
All other elements in the gaming area are hidden for non-active
players. This design issue became important after the first user
tests and because of two reasons: First, the active player is clearly
identified by his active elements on the table. Second, non-active
users may put their arms on the table to feel comfortable without
evocation of a software reaction.</p>
        <p>The chips on a player area are typically used to visualize the
player’s available amount, as well as to place bet and call
amounts. The players place their chips by simply moving them
into the bet area with their fingers.</p>
        <p>In addition, two buttons are provided in the player area to easily
raise the pot with an “all in” (if possible) and to fold.</p>
        <p>The second important area on the board is the public area with all
common board cards. As typical for a Texas Hold’Em, the dealer
uncovers the five cards round by round.
Each round, another player becomes the formal dealer for this
round. As the software covers nearly all dealer responsibilities,
the dealer button on the board only serves as a marker to indicate
who starts a betting phase.</p>
        <p>For Poker beginners in particular, the values of their different
hands (along with consequences for their further play) may be
unclear. That’s why we introduced a help sheet to make the
introduction of Poker rules more effective.</p>
        <p>At the end of each game, the software announces the winner(s)
and uncovers the winning cards. The other players may
voluntarily uncover their cards as well, or may decide to still hide
them to prevent other players from deriving their strategy.
During the game, a menu symbol allows to setup, start or cancel a
Poker game. In addition, it provides the possibility to raise the
blinds during a game.</p>
        <p>Beyond a standard game course including logging mechanisms,
the Poker@PixelSense system may run in a training mode without
logging to introduce new players to Poker in general as well as to
this special software.</p>
      </sec>
    </sec>
    <sec id="sec-8">
      <title>3.2 Gathering and Logging Data</title>
      <p>The main goal of our Poker game is data collection for the
psychological experiments on decision making. Thus, logging of
the game status and all player activities is one of the central
functionalities of Poker@PixelSense.</p>
      <p>All player activities are stored in a simple text-based log file.
Figure 5 shows an excerpt of a typical log. Each line in the text
file stores details of one activity. The nine attributes of the activity
are separated by semicolons.</p>
      <p>Each activity is identified by a timestamp. This is followed by the
name of the acting player or “dealer” if the software performs this
task. The next attributes are the action that was carried out, the
current amount of the player, the hand cards of the player as well
as the common board cards and the current pot value. For an easy
interpretation of the player’s decision the software calculates the
win probability of the current player based on his hand cards and
the common board cards.
Figure 5 highlights the four bet rounds of a typical Texas Hold'Em
game that can be tracked in the log file. During the preflop round
each player only knows his two hand cards. At timestamp 575930,
the dealer discovers the first 3 board cards (flop). This round is
followed by discovering the turn card (timestamp 628265) and the
final bet round (river card) with all cards discovered (timestamp
646974).</p>
      <p>During the rounds, the win probabilities of players change and
they adapt their activities. For instance, player 14 has a win
probability of 68% in the preflop round (timestamp 529349). He
decides to raise by only 100 credits. In the turn card round, player
14 wins by a probability of 88% and bets the high amount of 1000
credits.</p>
      <p>We decided to use a simple plain text format to log the actions.
CSV files can be easily read and edited with any text editor or
data analysis tool. Moreover, this helps to minimize the
integration effort when using the file as input format for another
software tool.</p>
    </sec>
    <sec id="sec-9">
      <title>3.3 Preparing the Lab Setting</title>
      <p>As already mentioned the investigator has the responsibility to
setup and monitor the experiment.</p>
      <p>After defining date and time of the game as well as the involved
players, he or she prepares the given lab environment in order to
achieve a comfortable, casino-like atmosphere. This can be
addressed by a quiet room with closed sun-blinds (better are
curtains), comfortable seats, some snacks and drinks, as well as
dimmed light.</p>
      <p>Moreover, the investigator has to care for requirements of the
technical environment. Technology does also benefit from
dimmed light, since the touch recognition hardware is based on
optical pattern recognition. A direct and bright light incidence
massively disturbs the recognition and must be prevented.
Furthermore, configuration of the game has to be carried out.
Rules are explained to the players, and a pre-phase for training on
the software takes place. Afterwards, the experiment itself starts,
consisting of 10 rounds of Poker. Beyond automated recording of
the game, additional information on attitudes, motivation and
emotions of the players is gathered in between rounds via an
online survey on a tablet computer.</p>
      <p>Finally, the investigator is responsible to save the log file for
further analysis at the end of an experiment.</p>
    </sec>
    <sec id="sec-10">
      <title>4. FINDINGS FROM EXPERIMENTS</title>
      <p>When the Poker@PixelSense prototype was completed, we
carried out some beta tests with interested colleagues and students
from our team in order to identify weaknesses and possible
improvements of the system. This was also used to verify if logics
and handling of the game are appropriate, especially if the
implemented mechanisms to reveal one’s personal cards are
suitable. This could be confirmed, and the system is now available
in a stable version.</p>
      <p>Starting from summer 2014, we conducted the experiments. The
sample consists of about 60 players, formed to groups of 4 to 6
players according to their level of Poker experience and their
availability on-site. This results in more than 30.000 activities
logged during the experiments (around 10 MB of logging data).
Players are University students from different disciplines.
The usefulness of the gathered data for psychological research is
very high, since the players’ behavior is directly recorded by the
gaming environment itself. This is real behavioral data, which is
extremely useful because it is very valid and exact. This is in
strong contrast to other approaches based on self-reports, since it
is not biased by memory effects or individuals’ motivation.
Moreover, the data is immediately recorded during the decision
making process, without distracting players from their game,
which is a great benefit for accuracy and expressiveness of the
gathered data. Finally, automated recording saves a lot of time and
money, as the alternative would be to have students record the
information while watching the players. This data can then be
combined with the data assessed through the online survey,
allowing for complex statistical models of participants’ cognition,
motivation, emotion, and actual behavior.</p>
      <p>At the time this article is finalized, most of the experiments are
successfully completed. A first analysis of the gathered data
promises interesting insights on decision-making strategies and
motivational processes of Poker players. Results of the upcoming
in-depth analysis will be prepared for further discussion in the
scientific community. The aim is to learn from this well-defined
game setting how surrounding conditions influence personal
motivation and decision making, in order to transfer these findings
to other fields which are harder to study.</p>
      <p>From a technical point of view, the suitability of the tactile Poker
game could be proven. Only minimal problems were reported by
the players, which could be quickly solved on-site and did not
influence the experiments.</p>
    </sec>
    <sec id="sec-11">
      <title>5. CONCLUSION AND FURTHER WORK</title>
      <p>In this article we present the development of a digital Poker game
on a touch-based, table-sized computer. The main objective was
to automatically gather most accurate and immediate information
on the status of the game and the activities of the players, in order
to study their motivation and decision making. Thus, a second
objective (with even higher impact on the design process) was to
create a tactile gaming application which is as close as possible to
a common casino-like game. We identified the requirements that
come along with these objectives, analyzed existing software and
described our design approach to fulfill these requirements.
As a result from this objective, and in contrast to previous work,
we decided to integrate the private areas of the players directly
into the game table. We could show that this is a suitable
approach, since like in traditional settings players simply cover
their cards with their hands when slightly uncovering them. Thus,
complex mechanisms for coupling the table with mobile phones
of the players could be avoided. Again, this makes it easier to
gather synchronized data on the game.</p>
      <p>Analysis of recorded data is subject of current work. Additionally,
we think about possible improvements. A higher degree of
immersion could be reached by using physical gaming cards, as
far as they can be recognized by the table. A solution to
circumvent the infra-red sensors’ problem in detecting red color
could be to use old German gaming cards (with black and green
instead of black and red symbols). However, this will be hard for
Poker games, but rather suitable for Skat or the like. Finally, the
recognition resolution of the table still has to improve in order to
detect card symbols of regular size. Extended usability studies
with players could then reveal whether these changes produce a
more realistic and sound game flow than exclusively playing with
digital cards.</p>
      <p>The flexibility of the system would further allow for programming
specific experimental manipulations, such as non-random game
flow or “planned” gains or losses for certain players. This would
enable us to study specific situational influence factors or events.
Experimentally manipulating these factors would further
strengthen the causality of the observed effects.</p>
      <p>Beyond studying players’ behavior in different types of games,
the approach of in-situ monitoring could be of certain value also
to other fields. This includes complex business simulations,
group-based problem solving etc. Moreover, the experimental
setup could be extended to further sources of data. With regard to
individual decision making, information on physiological data
would add to the explanatory value of the gathered data.
Indicators such as participants’ heart rate or blood pressure could
be used to investigate the psycho-physiological processes behind
decision-making, such as situation-induced strain. In addition to
logging information on individuals’ touching of certain features
on the display, eye-tracking devices could provide more
information on information-seeking behavior prior to actually
touching the display. Video recording could be used to document
the social interaction and communication between actors, which
would be particularly interesting in group task simulations.
Increasing the complexity of the obtainable data will improve the
precision with which we can map and predict individuals’
decision-making and behavior. However, the variety of sensors
involved in such an experiment would require a complex
infrastructure to ensure synchronicity and interoperability of
related data and tools. This is an important subject of upcoming
research in our group.</p>
    </sec>
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