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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>You Are What You Post: What the Content of Instagram Pictures Tells About Users' Personality</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Bruce Ferwerda</string-name>
          <email>bruce.ferwerda@jku.at</email>
          <email>bruce.ferwerda@ju.se</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Author Keywords</string-name>
          <xref ref-type="aff" rid="aff3">3</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>*Also affiliated with the Department of Computational Perception,</string-name>
          <email>tria), bruce.ferwerda@jku.at</email>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Marko Tkalcic</string-name>
          <email>marko.tkalcic@unibz.it</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Department of Computer Science and Informatics, School of Engineering, Jönköping University</institution>
          ,
          <addr-line>P.O. Box 1026, SE-551 11, Jönköping</addr-line>
          ,
          <country country="SE">Sweden</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Faculty of Computer Science, Free University of Bozen-Bolzano</institution>
          ,
          <addr-line>Piazza Domenicani 3, I-39100, Bozen-Bolzano</addr-line>
          ,
          <country country="IT">Italy</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Johannes Kepler University</institution>
          ,
          <addr-line>Altenberger Strasse 69, 4040, Linz (Aus</addr-line>
        </aff>
        <aff id="aff3">
          <label>3</label>
          <institution>Personality</institution>
          ,
          <addr-line>Instagram, picture content, social media</addr-line>
        </aff>
      </contrib-group>
      <abstract>
        <p>Instagram is a popular social networking application that allows users to express themselves through the uploaded content and the different filters they can apply. In this study we look at the relationship between the content of the uploaded Instagram pictures and the personality traits of users. To collect data, we conducted an online survey where we asked participants to fill in a personality questionnaire, and grant us access to their Instagram account through the Instagram API. We gathered 54,962 pictures of 193 Instagram users. Through the Google Vision API, we analyzed the pictures on their content and clustered the returned labels with the k-means clustering approach. With a total of 17 clusters, we analyzed the relationship with users' personality traits. Our findings suggest a relationship between personality traits and picture content. This allow for new ways to extract personality traits from social media trails, and new ways to facilitate personalized systems.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>
        INTRODUCTION
Personality traits have shown to be a useful concept to rely
on when considering personalizations of user experiences in
a system. This because personality has shown to be a stable
construct over time, and reflects the coherent patterning of
one’s affect, cognition, and desires (goals) as it leads to
behavior [
        <xref ref-type="bibr" rid="ref23">22</xref>
        ]. The stability and coherency that personality bring, has
shown to be useful for systems to infer users’ preferences and
to provide personalized experiences to users (e.g., [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]).
Systems that use personality-based personalizations have shown
©2018. Copyright for the individual papers remains with the authors.
Copying permitted for private and academic purposes.
      </p>
      <p>
        HUMANIZE ’18, March 11, 2018, Tokyo, Japan
to have an advantage over systems not using personality
information [
        <xref ref-type="bibr" rid="ref16">15</xref>
        ]; an advantage is created in terms of increased
users’ loyalty towards the system and decreased cognitive
effort.
      </p>
      <p>
        The usefulness of personality for personalization is shown
in its domain independency: once the personality of users is
known, it can be used across domains for personalization [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ].
This allows for personality extraction in one domain and
implementation in another. Hence, the relationships between
personality traits and users’ behavior preferences and needs
are increasingly being investigated (e.g., health [
        <xref ref-type="bibr" rid="ref15 ref26">14, 25</xref>
        ],
education [
        <xref ref-type="bibr" rid="ref20 ref3">3, 19</xref>
        ], movies [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ], music [
        <xref ref-type="bibr" rid="ref10 ref12 ref27 ref5 ref6 ref7 ref8">6, 8, 5, 7, 11, 26</xref>
        ],
marketing [
        <xref ref-type="bibr" rid="ref21">20</xref>
        ]) in order to learn about the connection between
personality traits and specific behaviors.
      </p>
      <p>
        Since personality traits of users are increasingly being used
to provide a personalized experience to users, there is an
increased interest in how to implicitly acquire these traits for
implementation. A useful source of information are social
networking services (SNSs). SNSs are increasingly
interconnected with applications through so called "single sign-on
buttons" (SSO buttons). 1 The abundance of information that
becomes available from the connected SNSs can be used to
infer users’ personality traits from (e.g., Facebook [
        <xref ref-type="bibr" rid="ref10 ref7">7</xref>
        ],
Twitter [
        <xref ref-type="bibr" rid="ref22 ref25">21, 24</xref>
        ], and Instagram [
        <xref ref-type="bibr" rid="ref11 ref9">9, 10</xref>
        ]).
      </p>
      <p>
        In this work we join the personality extraction research. We
specifically focus on Instagram, a popular mobile
photosharing, and SNS, with currently over 800 million users. 2
With the content as well as with the filters that Instagram
allows users to apply to their pictures, users are able to express
a personal style and create a seeming distinctiveness. Hence,
personality information about users may be hidden in the
pictures that users upload to Instagram. Whereas prior work on
Instagram focused on the picture properties (i.e., hue,
saturation, valence relationship) [
        <xref ref-type="bibr" rid="ref11 ref9">9, 10</xref>
        ], we focus on the content of
the posted pictures on Instagram and explore the relationship
with the personality traits of Instagram users. By analyzing the
Instagram pictures on their content using the Google Vision
1Buttons that allow users to easily register and log in to a system
with their social media account.
2 https://instagram.com/press/ (accessed: 08/12/2017)
API 3, we were able to find distinct correlations between users’
personality traits and the content of the pictures they post on
Instagram.
      </p>
      <p>
        RELATED WORK
There is an increasing body of work that looks at how to
implicitly acquire personality traits of users. Since all kind of
information can relate to personality traits, even information
that is not directly relevant for a specific purpose may contain
information that is useful for the extraction of personality
(e.g., Facebook [
        <xref ref-type="bibr" rid="ref10 ref7">7</xref>
        ], Twitter [
        <xref ref-type="bibr" rid="ref22 ref25">21, 24</xref>
        ], and Instagram [
        <xref ref-type="bibr" rid="ref11 ref9">9, 10</xref>
        ]).
The increased connectedness between SNSs and applications
through SSO buttons provide an abundance of information
that can be exploited to implicitly acquire personality traits of
users.
      </p>
      <p>
        Quercia et al. [
        <xref ref-type="bibr" rid="ref22">21</xref>
        ] looked at Twitter profiles and were able
to predict users’ personality traits by using their number of
followers, following, and listed counts. With these three
characteristics they were able to predict personality scores with
a root-mean-square error 0.88 on a [
        <xref ref-type="bibr" rid="ref1 ref5">1,5</xref>
        ] scale. Similar work
has been done by Golbeck, Robles, and Turner [
        <xref ref-type="bibr" rid="ref14">13</xref>
        ] on
Facebook profiles. They mainly looked at the sentiment of posted
content and were able to create a reliable personality predictor
with that information. A more comprehensive work on the
prediction of personality and other user characteristics using
Facebook likes has been proposed by Kosinski, Stillwell and
Graepel [
        <xref ref-type="bibr" rid="ref19">18</xref>
        ].
13 }, {
14
Besides posted content on SNSs, the characteristics of pictures 15
has shown to consist of personality information as well. Celli, 16
Bruni, and Lepri [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] showed that Facebook profile pictures 17 }, {
consist of indicators of users’ personality. An extension of 18
this work has been recently published [
        <xref ref-type="bibr" rid="ref24">23</xref>
        ]. Work of Ferwerda, 19
Schedl, and Tkalcic [
        <xref ref-type="bibr" rid="ref11 ref13">12, 10</xref>
        ] on Instagram pictures, showed 20
that the way filters are applied to create a certain
distinctiveness that can be used to predict personality traits of the poster. 21 }, {
In this work we expand the work of Ferwerda et al. [
        <xref ref-type="bibr" rid="ref11 ref13">12, 10</xref>
        ]
on Instagram pictures. Instead of looking at the picture
characteristics (i.e., how filters are applied), we look at the posted
content itself.
      </p>
      <p>
        METHOD
To investigate the relationship between personality traits and
picture features, we asked participants to fill in the 44-item
BFI personality questionnaire (5-point Likert scale; Disagree
strongly - Agree strongly [
        <xref ref-type="bibr" rid="ref17">16</xref>
        ]). The questionnaire includes
questions that aggregate into the five basic personality traits
of the FFM. Additionally, we asked participants to grant us
access to their Instagram account through the Instagram API,
in order to crawl their pictures.
      </p>
      <p>
        We recruited 233 participants through Amazon Mechanical
Turk, a popular recruitment tool for user-experiments [
        <xref ref-type="bibr" rid="ref18">17</xref>
        ].
Participation was restricted to those located in the United States,
and also to those with a very good reputation ( 95% HIT
approval rate and 1000 HITs approved) 4 to avoid careless
3https://cloud.google.com/vision/
4HITs (Human Intelligence Tasks) represent the assignments a user
has participated in on Amazon Mechanical Turk prior to this study.
contributions. Several control questions were used to filter
out fake and careless entries. This left us with 193 completed
and valid responses. Age (18-64, median 30) and gender (104
male, 89 female) information indicated an adequate
distribution. Pictures of each participant were crawled after the study.
This resulted in a total of 54,962 pictures.
      </p>
      <p>
        To analyze the content of the pictures, we used the Google
Vision API. The Google Vision API uses a deep neural
network to analyze the pictures and assign tags ("description")
with a confidence level ("score": re [
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ]) to classify the
content (example given in Listing 1).
Using the Google Vision API, we were able to retrieve 4090
unique labels from the Instagram pictures. In order to create
an initial clustering of the labels, we used a k-means
clustering method that is applied to the vectors that represent the
terms in the joint vector space. The vectors were generated
with the doc2vec approach using a set of embeddings that are
pre-trained on the English Wikipedia 5. Using this method we
collated the labels into 400 clusters. 6 After that, the output of
the k-means was manually checked and the clusters were
further (manually) collated into similar categories. This resulted
into 17 categories representing:
5https://github.com/jhlau/doc2vec
6The k-means clustering method allows for setting a parameter for
the number of clusters to be forced. Different number of clusters were
tried out. Setting the k-means to automatically define 400 clusters
resulted in clusters with least errors in clustering the labels.
1. Architecture
2. Body parts
3. Clothing
4. Music instruments
5. Art
6. Performances
7. Botanical
8. Cartoons
9. Animals
10. Foods
11. Sports
12. Vehicles
13. Electronics
14. Babies
15. Leisure
16. Jewelry
17. Weapons
      </p>
      <p>
        For each participant, we accumulated the number of category
occurrences in their Instagram picture-collection. Since the
number of Instagram pictures in each picture-collection is
different, we normalized the number of category occurrences
to represent a range of re [
        <xref ref-type="bibr" rid="ref1">0,1</xref>
        ]. This in order to be able to
compare users with differences in the total amount of pictures.
RESULTS
We used the Spearman’s correlation analysis to analyze the
correlations between the picture content categories and
personality traits. Alpha levels were adjusted using the Bonferroni
correction to limit the chances of a Type I error. The reported
significant results adhere to alpha levels of p &lt;.001 (see
Table 1). Several correlations were found that indicate a higher
usage of posting pictures with a certain content depending on
personality traits. The correlations between the picture content
categories and personality traits are discussed below.
      </p>
      <p>Openness to experience: Openness to experience was found
to correlate with the music instruments category (category
#4). This shows that those scoring high in the openness to
experience trait in general post more pictures consisting of
music instruments.</p>
      <p>Conscientiousness: A positive correlation was found
between conscientiousness and the categories #3 (clothing)
and #11 (sports). This indicates that conscientious participants
more frequently shared pictures consisting of content with
clothing or sports.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17</p>
      <p>Extraversion: We found a correlation between
electronics (category #13) and extraversion. Extraverts tend
to post pictures on their Instagram account consisting of
electronics.</p>
      <p>Agreeableness: Positive correlations were found
between agreeableness and the the categories #3 (clothing)
and #15 (leisure). This means that the Instagram
picturecollections of agreeable participants consist of pictures with
clothing or leisure content.</p>
      <p>Neuroticism: A negative correlation was found with
category #3 (clothing) and a positive correlation was found
with category #16 (jewelry) and those scoring high on
neuroticism. The results show that people who score high on
neuroticism tend to have less pictures with clothing content,
but in general have more content with jewelry.</p>
      <p>CONCLUSION AND OUTLOOK
We found the content of Instagram picture features to be
correlated with personality. A summary of the correlations between
the picture content and personality traits can be found in
Table 2.</p>
    </sec>
    <sec id="sec-2">
      <title>Personality</title>
      <p>Openness to experience
Conscientiousness
Extraversion
Agreeableness
Neuroticism</p>
    </sec>
    <sec id="sec-3">
      <title>Picture content</title>
      <p>Music instruments
Clothing, sports
Electronics
Clothing, leisure
Clothing (-), jewelry</p>
      <p>
        The identification of the correlations between image categories
and user personality is the first step towards unobtrusive
personality detection and personalization. In future work we plan
to use the automatically detected categories as features for the
unobtrusive prediction of personality using machine learning
techniques. With this work we are complementing prior work
of Ferwerda et al. [
        <xref ref-type="bibr" rid="ref11 ref13">12, 10</xref>
        ] in which they used the picture
properties of Instagram pictures to find relations with personality
traits as well creating a predictive model of personality traits.
Future work will focus on combining the relevant picture
features of prior work with the categories that we laid out in this
work to improve the predictive models that can be created for
personality prediction.
      </p>
      <p>ACKNOWLEDGEMENTS
We would like to thank Marcin Skowron for his help and
expertise on processing the data into clusters.</p>
    </sec>
  </body>
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