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      <title-group>
        <article-title>Opportunities and Challenges in Mining Behavioral Economics to Design Persuasive Technology</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Min Kyung Lee</string-name>
          <email>mklee@cs.cmu.edu</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Human-Computer Interaction Institute Carnegie Mellon University Pittsburgh</institution>
          ,
          <addr-line>PA 15213</addr-line>
          <country country="US">USA</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>Behavioral economics examines people's decision making processes in everyday situations. I argue that behavioral economics can provide a repertoire of a tool that can inform the design of persuasive technology. In this position paper, I propose strategies drawn from behavioral economics, and identify opportunities and challenges in applying the strategies to the design of persuasive technology. This position paper is a modification of the paper [16].</p>
      </abstract>
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      <title>-</title>
      <p>
        APPLYING BEHAVIORAL ECONOMICS
Departing from the premise of economics that people make
rational choices, behavioral economists have shown that
people’s decision making processes are biased by various
situational factors, such as the manner in which options are
presented and the times when the choices are offered, and
the emotional or visceral state of the person at the time of
choice [
        <xref ref-type="bibr" rid="ref1 ref12">1, 12</xref>
        ]. This understanding of people’s decision
biases provides a rich repertoire of tools that designers can
leverage. In this section, we present five decision biases and
discuss how these biases can be leveraged in the design of
persuasive technology.
      </p>
      <p>
        Default Bias
When people make choices, they tend to favor the default
option or the status quo, rather than taking the time to
consider and then adopt an alternative state [
        <xref ref-type="bibr" rid="ref11 ref21">11, 21</xref>
        ]. People
tend to take “the path of least resistance,” and keep doing
what they have been doing, or doing what comes
automatically, even when they can make improvements.
The reasons for this decision bias could have roots in
people’s limited attention and tendency to “satisfice” [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ],
their perception that an organization’s selection of a default
option constitutes a recommendation (see [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]), and the
implied popularity of the default option.
      </p>
      <p>
        Default biases have been blamed for a wide range of
undesirable outcomes, including Americans’ excessive
consumption of fries and large sodas as part of “supersized”
meals at McDonald’s [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ]. Yet if carefully designed, the
default bias can be a powerful tool to propel people toward
self-beneficial behaviors (see [
        <xref ref-type="bibr" rid="ref23 ref5">5, 23</xref>
        ]).
      </p>
      <p>Opportunities
Convenience and salience. HCI design can leverage the
default bias in many ways, by making healthy choices more
convenient and salient physically and cognitively. In the
domain of snacking, featured healthy snacks can be made
easy to access, e.g., on websites, on vending carts, and so
forth. For example, on a website, the checkbox of healthy
snacks among available options could be selected as the
default, reducing the need to select one of these options
explicitly. Or when presenting sale items at a bakery, a
system could filter and first offer items that are made with
whole grain flours. For a kiosk system, the placement of
buttons, the number of clicks or the number of screens a
user has to access to choose an item could be decreased or
increased to change the perceived priority of a snack or
sandwich order.</p>
      <p>An eldercare robot working in a nursing home could
organize the physical placement of food in a way that the
healthy food is placed closer to an elder’s room. In addition,
a snack delivery robot might only deliver healthy snacks to
people’s offices, but require people to walk to the robot to
get unhealthy snacks.</p>
      <p>Convenience can be further leveraged using sensing
technologies that tell people when they are near healthy
snacks. For instance, if shoppers are in a food court in a
mall, the system could present healthy choices to them via
mobile phone as convenient food options.</p>
      <p>
        Default bias is different with other biases presented in the
paper; leveraging default bias can be effective, even with
those who are not motivated to change their potentially
problematic behaviors, or are not aware of issues with their
current behaviors [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ].
      </p>
      <p>
        Attention span. People might be more subject to default
bias when their attention spans are limited or when they do
not have enough time to do exhaustive search. HCI
technology can target moments when people’s attention
spans are limited, such as when they are using mobile
devices on the move, or when people are making decisions
with limited time, such as when they are ordering food in a
fast-food restaurant, or making choices in a public kiosk.
Interface components can be also designed to manipulate
people’s attention spans. The use of banners or graphic
images may be distracting [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ], reducing people’s
attentiveness and efforts in making decision.
      </p>
      <p>
        Challenges
Depending on the way it is implemented, the default
strategy may harm people’s experience of making a choice
[
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]. Explicitly suggesting a certain options as default may
cause people to feel forced to make those choices. Careful
design of the strategy and iterative testing of its efficacy
and its impact on people’s experiences will be important.
Another caveat in using default strategy might be its lack of
educational effect. In comparison to persuasive techniques
that use informative messages (e.g., indicating
consequences of choices), the default strategy do not
provide any information that people can use to reflect on
their behaviors and learn the consequences of their choices.
If users are subsequently put in a new environment without
the interventions, the changed behaviors may not continue.
Designers using the default strategy should be aware of this
potential problem, and consider using them with
educational methods. New research is needed to understand
the long-term effects of these techniques.
      </p>
      <p>
        Present-biased preference
Present-biased preferences represent people’s tendency to
weigh the pros and cons of present choices more heavily
than future choices, and to underestimate their needs in the
future. This decision bias is also known as “time
discounting” [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]. The tendency typically promotes
unhealthy eating because the immediate pull of tasty food is
likely to eclipse considerations of future health
consequences. However, present-biased preferences can be
used to encourage healthier choices if people are asked to
plan ahead. Read and van Leeuwen [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ] gave their
participants a choice of snack to be eaten in one week or at
the time of eating, the next week. They found that their
participants chose far more unhealthy snacks for immediate
choice than for advance choice.
      </p>
      <p>
        Opportunities
Strategic design of timing of choice. Present-biased
preferences can be leveraged by strategically designing the
time that technology applications prompt users to make
certain choices. Researchers in context-aware technology
have been designing applications that can sense the current
activity of people and learn their routines over time [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. A
meal planning application or a restaurant reservation system
that nudges people to make a choice when they are less
likely to be hungry (i.e., 1-2 hours after their lunch) might
be as effective as the application that uses persuasive
messages or calorie information, and it might be felt to be
less intrusive.
      </p>
      <p>Challenges
The success of the planning strategy may depend on
people’s satisfaction with the choice made previously at the
time of consumption. Even when people spontaneously
made choices that would have long-term benefits and
delayed gratification (e.g., granola bars over more delicious
chocolate bar), they may not like their choices anymore at
the moment when they experience the outcomes of their
choices. If this experience continues, people may stop using
the technology or change their minds at the time of
consumption. Systems would need to help people stick with
their choices and influence them to stay happy with their
choices. Messages that remind people of the positive
aspects of their choices may mitigate potential negative
feelings.</p>
      <p>
        Diversification heuristic
Diversification heuristic or naïve diversification means
people’s tendency to seek variety when making several
choices at once [
        <xref ref-type="bibr" rid="ref20 ref22">20, 22</xref>
        ]. This bias applies to a lesser degree
when people make the same type of choices sequentially
over time. For example, when people are asked to pick four
snacks for one month at once, they tend to choose four
different snacks; on the other hand, when people are asked
to pick a snack each week, they tend to choose their favorite
snack, having the same four snacks for one month.
Opportunities
Diversification heuristic can be leveraged by prompting
people to make another choices for the future when they
make short-sighted choices. For example, when people
order an unhealthy snack to eat immediately, the system can
prompt them to make a choice for their next snack. Both
diversification heuristic and present-biased preference
suggest that people are more likely to choose healthy
snacks as their next snack. On the other hand, when people
make healthy choices for immediate consumption, the
system may not prompt them for future choices, so that they
do not choose unhealthy choices for the sake of diversity.
Challenges
Providing incentives for people to make choices for future
(e.g., a discount) will be important to encourage people to
take another step to make a future choice.
      </p>
      <p>
        Licensing effect
Licensing effect refers to people’s tendency to indulge
themselves (i.e., making vice choices) after they make
choices that activate a positive self-concept (i.e., making
virtue choices) [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ]. For example, people may feel that they
deserve a high-caloric dessert after having a healthy salad
for lunch. Some research suggests that prior choices can
influence subsequent choices even in different domains. For
instance, after donating their money to a charity, people
may feel licensed to buy a luxurious item for themselves.
Opportunities
Persuasive technology can adaptively change its
information presentation to help people avoid licensing
effect biases. In a system that tracks people’s previous
choices, when they have made virtuous choices (e.g.,
exercising instead of watching TV on a couch, or
carpooling instead of driving), the system may not show or
emphasize the tracked behaviors in order not to encourage
any licensing behaviors.
      </p>
      <p>
        Challenges
There is little consensus on how people make decisions in
responses to their prior choices. Transtheoretical model
suggests that the system needs to applaud people making
progresses in changing their behaviors in relation to their
goals [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. Licensing effects suggest that emphasizing their
previous good behaviors can induce people to feel deserved
to deviate from the good behaviors. More research is
needed to better understand what factors cause the
differences in their subsequent choices [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ].
      </p>
      <p>
        Asymmetrically dominated choices
People tend to make choices that are easier to judge as
superior than other alternatives. One example of this
tendency is the “asymmetric dominated choice” [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ], which
means placing a choice option next to an inferior option to
increase its attractiveness.
      </p>
      <p>Opportunities
Asymmetrically dominated choices can be leveraged by
intentionally including an inferior option when presenting
many options. For instance, consider a cookie as compared
to a large, shiny Fuji apple and a small withered apple. By
pairing the Fuji with the withered apple, the Fuji’s value
seems much higher, and choices of the Fuji will increase.
Challenges
Paring only a few options with obviously inferior ones can
make users feel suspicious about the systems. In addition,
in many choices, finding a clearly inferior option is
difficult, which makes this approach practical only to a
certain type of choices.</p>
      <p>
        NEEDS FOR SYSTEMATIC DESIGN AND EVALUATION
In the previous sections, I described several decision biases
drawn from behavioral economics, and opportunities and
challenges in leveraging them in the design of persuasive
technology. Theory-based design should be implemented
through iterative design processes and evaluated
systematically to test its efficacy as documented in [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ].
Previous research has showed that some design features do
not work in the real world, even when theory predicted their
effect [
        <xref ref-type="bibr" rid="ref1 ref16">1, 16</xref>
        ]. In the real world, there might be other factors
that may eclipse the power of the intervention strategy.
Characteristics of different design media (website, mobile
phone, and/or robot) can influence how theory would work.
CONCLUSION
Behavioral economics research suggests that extremely
simple changes in user interfaces can have a substantial
impact on people’s choices. In this workshop, I hope to
have a lively discussion on strengths and weaknesses of
design strategies drawn from behavioral economics, and
identify domains and situations where these approaches
would be most appropriate and useful.
      </p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <surname>Beenen</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ling</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Wang</surname>
            ,
            <given-names>X.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chang</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Frankowski</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Resnick</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          , and
          <string-name>
            <surname>Kraut</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          (
          <year>2004</year>
          ).
          <article-title>Using social psychology to motivate contributions to online communities</article-title>
          .
          <source>In Proceedings of CSCW'04</source>
          ,
          <fpage>212</fpage>
          -
          <lpage>221</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          2.
          <string-name>
            <surname>Burke</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Hornof</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Nilsen</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          , and
          <string-name>
            <surname>Gorman</surname>
            ,
            <given-names>N.</given-names>
          </string-name>
          (
          <year>2005</year>
          ).
          <article-title>High-cost banner blindness: Ads increase perceived workload, hinder visual search, and are forgotten</article-title>
          .
          <source>ACM Transactions on Computer-Human Interaction</source>
          ,
          <volume>12</volume>
          ,
          <issue>4</issue>
          ,
          <fpage>423</fpage>
          -
          <lpage>445</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          3.
          <string-name>
            <surname>Camerer</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Issacharoff</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Samuel</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Loewenstein</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          (
          <year>2003</year>
          ).
          <article-title>Regulation for Conservatives: Behavioral Economics and the Case for "Asymmetric</article-title>
          <string-name>
            <surname>Paternalism.</surname>
          </string-name>
          " University of Pennsylvania Law Review,
          <volume>151</volume>
          ,
          <fpage>1211</fpage>
          -
          <lpage>1254</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          4.
          <string-name>
            <surname>Dey</surname>
            ,
            <given-names>A. K.</given-names>
          </string-name>
          (
          <year>2001</year>
          ).
          <article-title>Understanding and using context</article-title>
          .
          <source>Journal of Personal and Ubiquitous Computing</source>
          ,
          <fpage>4</fpage>
          -
          <lpage>7</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          5.
          <string-name>
            <surname>Downs</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Loewenstein</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Wisdom</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          (
          <year>2009</year>
          )
          <article-title>Strategies for promoting healthier food choices</article-title>
          .
          <source>American Economic Review</source>
          ,
          <volume>99</volume>
          ,
          <fpage>159</fpage>
          -
          <lpage>164</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          6.
          <string-name>
            <surname>Feldman</surname>
            ,
            <given-names>M.S.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>March</surname>
            ,
            <given-names>J.G.</given-names>
          </string-name>
          (
          <year>1981</year>
          ).
          <article-title>Information in organizations as signal and symbol</article-title>
          .
          <source>Administrative Science Quarterly</source>
          ,
          <volume>26</volume>
          (
          <issue>2</issue>
          ),
          <fpage>171</fpage>
          -
          <lpage>186</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          7.
          <string-name>
            <surname>Fogg</surname>
            ,
            <given-names>B.J.</given-names>
          </string-name>
          (
          <year>2002</year>
          ).
          <article-title>Persuasive technology: Using computers to change what we think and do</article-title>
          . Morgan Kaufmann.
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          8.
          <string-name>
            <surname>He</surname>
            ,
            <given-names>H. A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Greenber</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          , and
          <string-name>
            <surname>Huang</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          (
          <year>2010</year>
          ).
          <article-title>One size does not fit all: Applying the transtheoretical model to energy feedback technology design</article-title>
          .
          <source>In Proceedings of CHI'10</source>
          ,
          <fpage>927</fpage>
          -
          <lpage>936</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          9.
          <string-name>
            <surname>Huber</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Payne</surname>
            ,
            <given-names>J. W.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Puto</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          (
          <year>1982</year>
          ).
          <article-title>Adding asymmetrically dominated alternatives: Violations of regularity and the similarity hypothesis</article-title>
          .
          <source>Journal of Consumer Research</source>
          ,
          <volume>9</volume>
          ,
          <fpage>90</fpage>
          -
          <lpage>98</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          10.
          <string-name>
            <surname>Huber</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Goldsmith</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          , and
          <string-name>
            <surname>Mogilner</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          (
          <year>2008</year>
          ).
          <article-title>Reinforcement versus balance response in sequential choice</article-title>
          .
          <source>Marketing letters</source>
          ,
          <volume>19</volume>
          ,
          <fpage>229</fpage>
          -
          <lpage>239</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          11.
          <string-name>
            <surname>Kahneman</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Knetsch</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Thaler</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          (
          <year>1991</year>
          ).
          <article-title>Anomalies: The endowment effect, loss aversion, and status quo bias</article-title>
          .
          <source>Journal of Economic Perspectives</source>
          ,
          <volume>5</volume>
          ,
          <issue>1</issue>
          ,
          <fpage>193</fpage>
          -
          <lpage>206</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          12.
          <string-name>
            <surname>Kahneman</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          (
          <year>2003</year>
          ).
          <article-title>Maps of bounded rationality: Psychology for behavioral economics</article-title>
          .
          <source>American Economic Review</source>
          ,
          <fpage>1449</fpage>
          -
          <lpage>1475</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          13.
          <string-name>
            <surname>Khan</surname>
            ,
            <given-names>U.</given-names>
          </string-name>
          and
          <string-name>
            <surname>Dhar</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          (
          <year>2006</year>
          ).
          <article-title>Licensing effect in consumer choice</article-title>
          .
          <source>Journal of Marketing Research</source>
          ,
          <fpage>259</fpage>
          -
          <lpage>266</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          14.
          <string-name>
            <surname>Kahn</surname>
            <given-names>U.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Dhar</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          (
          <year>2007</year>
          ).
          <article-title>Where there is a way, is there a will? The effect of future choices on self-control</article-title>
          .
          <source>Journal of Experimental Psychology</source>
          ,
          <fpage>277</fpage>
          -
          <lpage>288</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          15.
          <string-name>
            <surname>Lee</surname>
            ,
            <given-names>M.K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Forlizzi</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Rybski</surname>
            ,
            <given-names>P.E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Crabbe</surname>
            ,
            <given-names>F.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chung</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Finkle</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Glaser</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Kiesler</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          (
          <year>2009</year>
          ).
          <article-title>The Snackbot: Documenting the design of a robot for longterm Human-Robot Interaction</article-title>
          .
          <source>In Proceedings of HRI'09</source>
          ,
          <fpage>7</fpage>
          -
          <lpage>14</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          16.
          <string-name>
            <surname>Lee</surname>
            ,
            <given-names>M. K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kiesler</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          , and
          <string-name>
            <surname>Forlizzi</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          <article-title>(in press). Mining behavioral economics to design persuasive technology for healthy choices</article-title>
          . To appear
          <source>in Proceedings of CHI'11.</source>
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          17.
          <string-name>
            <surname>Loewenstein</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brennan</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          and
          <string-name>
            <surname>Volpp</surname>
            ,
            <given-names>K.G.</given-names>
          </string-name>
          (
          <year>2007</year>
          ).
          <article-title>Protecting people from themselves: using decision errors to help people improve their health</article-title>
          .
          <source>Journal of the American Medical Association</source>
          .
          <volume>298</volume>
          (
          <issue>20</issue>
          ),
          <fpage>2415</fpage>
          -
          <lpage>2417</lpage>
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          18.
          <string-name>
            <surname>Loewenstein</surname>
            , G.,
            <given-names>O</given-names>
          </string-name>
          <string-name>
            <surname>'Donoghue</surname>
            ,
            <given-names>T.M.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Rabin</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          (
          <year>2003</year>
          ).
          <article-title>Projection bias in predicting future utility</article-title>
          .
          <source>Quarterly Journal of Economics</source>
          ,
          <volume>118</volume>
          ,
          <fpage>1209</fpage>
          -
          <lpage>1248</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          19.
          <string-name>
            <surname>Read</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          , &amp; van
          <string-name>
            <surname>Leeuwen</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          (
          <year>1998</year>
          ).
          <article-title>Predicting hunger: The effects of appetite and delay on choice</article-title>
          .
          <source>Organizational Behavior and Human Decision Processes</source>
          ,
          <volume>76</volume>
          (
          <issue>2</issue>
          ),
          <fpage>189</fpage>
          -
          <lpage>205</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          20.
          <string-name>
            <surname>Read</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Loewenstein</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          , and
          <string-name>
            <surname>Kalyanaraman</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          (
          <year>1999</year>
          ).
          <article-title>Mixing virtue and vice: Combining the immediacy effect and the diversification heuristic</article-title>
          .
          <source>Journal of Behavioral Decision Making</source>
          ,
          <volume>12</volume>
          ,
          <fpage>257</fpage>
          -
          <lpage>273</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref21">
        <mixed-citation>
          21.
          <string-name>
            <surname>Samuelson</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          &amp;
          <string-name>
            <surname>Zeckhauser</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          (
          <year>1988</year>
          ).
          <article-title>Status quo bias in decision making</article-title>
          .
          <source>Journal of Risk and Uncertainty</source>
          ,
          <volume>1</volume>
          ,
          <fpage>7</fpage>
          -
          <lpage>59</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref22">
        <mixed-citation>
          22.
          <string-name>
            <surname>Simonson</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          and
          <string-name>
            <surname>Tversky</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          (
          <year>1992</year>
          ).
          <article-title>Choice in context: Tradeoff contrast and extremeness aversion</article-title>
          .
          <source>Journal of Marketing Research</source>
          ,
          <fpage>28</fpage>
          -
          <lpage>295</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref23">
        <mixed-citation>
          23.
          <string-name>
            <surname>Thaler</surname>
            ,
            <given-names>R.H.</given-names>
          </string-name>
          &amp;
          <string-name>
            <surname>Benartzi</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          (
          <year>2004</year>
          ).
          <article-title>Save more tomorrow: Using behavioral economics to increase employee saving</article-title>
          .
          <source>Journal of Political Economy</source>
          ,
          <volume>112</volume>
          ,
          <fpage>164</fpage>
          -
          <lpage>187</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref24">
        <mixed-citation>
          24.
          <string-name>
            <surname>Thaler</surname>
            ,
            <given-names>R. H.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Sunstein</surname>
            ,
            <given-names>C. R.</given-names>
          </string-name>
          (
          <year>2008</year>
          ).
          <article-title>Nudge: Improving decisions about health, wealth, and happiness</article-title>
          . New Haven: Yale University Press.
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>