=Paper= {{Paper |id=Vol-2769/58 |storemode=property |title=AriEmozione: Identifying Emotions in Opera Verses |pdfUrl=https://ceur-ws.org/Vol-2769/paper_58.pdf |volume=Vol-2769 |authors=Francesco Fernicola,Shibingfeng Zhang,Federico Garcea,Paolo Bonora,Alberto Barrón-Cedeño |dblpUrl=https://dblp.org/rec/conf/clic-it/FernicolaZGBB20 }} ==AriEmozione: Identifying Emotions in Opera Verses== https://ceur-ws.org/Vol-2769/paper_58.pdf
          AriEmozione: Identifying Emotions in Opera Verses
            Francesco Fernicola1 , Shibingfeng Zhang1 , Federico Garcea1
                   Paolo Bonora2 , and Alberto Barrón-Cedeño1
                      1
                        Department of Interpreting and Translation
                           Università di Bologna, Forlı̀, Italy
                 2
                   Department of Classical Philology and Italian Studies
                          Università di Bologna, Bologna, Italy

             {francesco.fernicola, zhang.shibingfeng}@studio.unibo.it
                {federico.garcea2, paolo.bonora, a.barron}@unibo.it

                        Abstract                         whole (Zoppelli, 2001; McClary, 2012). Be-
                                                         ing able to automatically identify the emotions
    We present a new task: the identifi-                 expressed by the different arias of each work
    cation of the emotions transmitted in                would provide scholars with a useful tool for a
    Italian opera arias at the verse level.              systematic study of the repertoire. The tech-
    This is a relevant problem for the orga-             nology to identify the emotion(s) expressed by
    nization of the vast repertoire of Ital-             an aria represents an effective tool to study
    ian Opera arias available and to enable              the vast repertoire of arias and characters of
    further analyses by both musicologists               this period for musicologists and the lay pub-
    and the lay public.                                  lic alike. As an aria may express more than
    We shape the task as a multi-class su-               one emotion, we go one granularity level lower
    pervised problem, considering six emo-               —at the verse level. The task is defined as
    tions: love, joy, admiration, anger, sad-            follows:
    ness, and fear. In order to address it,              Identify the emotion expressed in a verse, in
    we manually-annotated an opera cor-                  the context of an aria.
    pus with 2.5k verses —which we re-
    lease to the research community— and                    In order to do that we created the
    experimented with different classifica-              AriEmozione 1.0 corpus: a collection of 678
    tion models and representations. Our                 operas with 2.5k verses, each of which has
    best-performing models reach macro-                  been manually annotated with respect to emo-
    averaged F1 measures of ∼0.45, always                tion. We experimented with different super-
    considering character 3-grams repre-                 vised models (e.g., SVMs, neural networks)
    sentations. Such performance reflects                and text (e.g., character n-grams and dis-
    the difficulty of the task at hand, par-             tributed representations).
    tially caused by the size and nature                    Our experiments show that, regardless of
    of the corpus, which consists of rel-                the model, character 3-grams outperform
    atively short verses written in 18th-                all other representations, reaching weighted
    century Italian.                                     macro-averaged F1 measures of ∼0.45. Under-
                                                         represented classes (e.g., fear) are the hard-
1   Introduction                                         est to identify. Others, such as anger and
                                                         sadness, being both negative, are often con-
Opera lyrics have the function of expressing
                                                         fused between each other.
the emotional state of the singing character.
In 17th- and 18th-century operas, characters                The rest of the contribution is dis-
brought on stage passions induced in their               tributed as follows. Section 2 describes the
souls by the succession of events in the drama.          AriEmozione 1.0 corpus. Section 3 describe
Musicological studies use these affects as one           the explored models and representations. Sec-
of the interpretative keys of the work as a              tion 4 discusses the experiments and obtained
                                                         results. Section 5 overviews some related
    Copyright ©2020 for this paper by its authors. Use
permitted under Creative Commons License Attribu-        work. Section 6 closes with conclusions and
tion 4.0 International (CC BY 4.0).                      proposals for future work.
 First of all, thank you for helping with this work.




                                                                                       ammirazione
 We are a group of researchers from the D. of Clas-




                                                                                                              tristezza
 sical Philology and Italian Studies and the D. of In-




                                                                                                                                  nessuna
                                                                                                     rabbia
                                                                       amore

                                                                               gioia




                                                                                                                          paura



                                                                                                                                            total
 terpreting and Translation, both at UniBO. Your
 work will help us to produce artificial intelligence
 models to analyse the lyrics in music.
                                                              train   289 274 289 414 503 166 38 1,973
 At this stage we are focused on opera. You will an-
                                                              dev      36 31 23 84 61 12 3         250
 notate arie in Italian from diverse periods, looking
                                                              test     37 39 30 64 54 15 11        250
 for the emotions that they express. Your work con-
                                                              overall 362 344 342 562 618 193 52 2,473
 sists of identifying the emotion expressed in each
 of the verses composing an aria. You can choose
 among six emotions (or none of them), which are             Table 1: AriEmozione 1.0 corpus statistics.
 defined next: [. . . ]

 Each row is divided in six columns:                        The first level of such tree includes six primary
 id A unique id, tied to the verse. Do not modify it.       emotions: love, joy, surprise, anger, sadness,
 verse A verse, inside of an aria. This is the text
 that you are going to analyse.                             and fear. Based on the nature of the material
 emotion Here you can select the expressed emotion          under review, we substitute surprise with ad-
 (or none of them)                                          miration, ending with the following six classes:
 emotion sec. This is available to choose a sec-
 ondary emotion, in case it is really difficult to choose   Amore (love) incl. affection, lust, longing.
 just one                                                   Gioia (joy) incl. cheerfulness, zest, content-
 confidence Not being 100% sure is ok. If that is
 the case, please let us know by choosing the right         ment, pride, optimism, enthrallment, relief.
 confidence level (default: “I am sure”).                   Ammirazione (admiration) admiration or
 comments Feel free to tell us something about this         adoration of someone’s talent, skill, or other
 instance, if you feel like.
                                                            physical or mental qualities.
Figure 1: Instructions given to the annotators              Rabbia (anger) incl. irritability, exaspera-
of the emotions in the AriEmozione 1.0 corpus.              tion, rage, disgust, envy, torment.
                                                            Tristezza (sadness) incl. suffering, disap-
                                                            pointment, shame, neglect, sympathy.
2   The AriEmozione 1.0 Corpus                              Paura (fear) incl. horror and nervousness.
                                                            An extra class nessuna (none) applies mostly
The corpus AriEmozione 1.0 is a subset of
                                                            to verses with non-actionable words only, ne-
the materials collected by project CORAGO.1
                                                            glected in the current experiments.
AriEmozione 1.0 contains a selection of 678 op-
                                                               Two native speakers of Italian annotated all
eras composed between 1655 and 1765. We
                                                            2,473 instances independently considering the
consider the lyrical text in the arias only. A.
                                                            instructions displayed in Figure 1. They were
Zeno and P. Metastasio are among the most
                                                            asked to include (i) the emotion transmitted
represented librettists in the corpus (∼ 30% of
                                                            by the verse, (ii) an optional secondary label
the operas); they are two of the most represen-
                                                            (in case they perceived a second emotion), and
tative and prolific librettists of the 18th cen-
                                                            (iii) their level of confidence: total confidence,
tury. All texts are written in the 18th century
                                                            partial confidence, or very doubtful.
Italian and articulated in verses and stanzas.
                                                               We measured the Cohen’s kappa inter-
   We labeled the emotions transmitted by ev-               annotator agreement (Fleiss et al., 1969) at
ery single verse, as we observed that this is the           this stage on the primary emotion. The re-
right granularity to obtain full text snippets              sult was 32.30, which is considered as a fair
expressing one single emotion. René Descartes              agreement. This value results from the per-
wrote in 1649 “Les passions de l’âme”, a sort              fect matching between the two annotators in
of compendium of all possible emotions and                  44% of the instances. When considering the
their possible causes (Garavaglia, 2018). For               secondary emotion as well, the two annota-
the sake of concreteness, we leveraged Par-                 tors coincided in 68% of the instances. These
rott’s (2001) tree of emotions classification.              numbers reflect the complexity of the task.
   1
     CORAGO is the Repertoire and archive of Ital-          The same annotators gathered together to dis-
ian opera librettos. It constitutes the first imple-        cuss and consolidate all dubious instances. Ta-
mentation of the RADAMES prototype (Repertori-              ble 1 shows the number of instances per class
azione e Archiviazione di Documenti Attinenti al Melo-
dramma E allo Spettacolo) (Pompilio et al., 2005);          for each corpus partition: training, develop-
http://corago.unibo.it.                                     ment, and test set. The verse average length
         id         verse                                                                             class
    ZAP1593570 03   Non ho più lagrime; non ho più voce; non posso piangere; non so parlar          Tristezza
                    I have no more tears; I have no more voice; I cannot cry; I
                    don’t know how to speak

    ZAP1596431 00   Barbaro! Oh dio mi vedi divisa dal mio ben; barbaro, e non concedi ch’io          Rabbia
                    ne dimandi almen
                    Barbarian! Oh Lord, you see me separated from my own good;
                    barbarian, you don’t even allow me but one demand

    ZAP1593766 01   Guardami e tutto obblio e a vendicarti io volo; di quello sguardo solo io         Amore
                    mi ricorderò
                    Look at me, all else is forgotten and I haste to avenge you;
                    only I shall remember that gaze

    ZAP1594229 00   Su la pendice alpina dura la quercia antica e la stagion nemica per lei fatal     Ammirazione
                    non è;
                    Up on the slope of the mountain the ancient oak tree still
                    lives on, and the adverse season poses no fatal threat

    ZAP1596807 00   In questa selva oscura entrai poc’anzi ardito; or nel cammin smarrito timido      Paura
                    errando io vo
                    I entered this dark forest not too long ago, boldly; having now
                    lost the path I wander around, shyly

    ZAP1599979 01   Vede alfin l’amate sponde, vede il porto, e conforto prende allor di riposar      Gioia
                    Finally, the beloved shores, the harbor, are all in sight and
                    with them come solace and sleep


Table 2: Instances from the AriEmozione 1.0 corpus, including unique identifier, verse in Italian
and English translation, and class. We include free (unofficial) translations for clarity.


is 72.5 ± 31.6 characters and the corpus con-                Model    Settings
                                                             k-NN     L2-Norm exploring with k ∈ [1, . . . 9].
tains 34, 608 (4, 458) tokens (types).2                      SVM      RBF; both explored with c                    ∈
   Table 2 shows examples of verses in the cor-                       [1, 10, 100, 1000] and γ ∈ [1e − 3, 1e − 4].
pus, including one of each of the six emotions.              Log Reg Multinomial Logistic Regression with
                                                                      Newton-CG solver.
                                                             NN       2 (3) hidden layers with size ∈
3       Models and Representations                                    [32, 64, 96, 128, 256] (∈ [8, 16, 32, 64, 96]);
                                                                      20% dropout; ReLu for input/hidden lay-
The nature of the corpus —a small amount of                           ers; softmax for output layer; categor-
                                                                      ical cross-entropy loss function; Adam;
short verses written in 18th-century Italian—
                                                                      epochs ∈ [1, . . . 15]
led us to select a humble set of models and                  FastText 300d embeddings with or without pre-
representation alternatives. The baseline is                          training; learning rate ∈ [0.3, 0.6, 1];
                                                                      epochs ∈ [1, 3, 5, 10, . . . , 100]
a k–Nearest Neighbors algorithm (kNN), con-
sidered thanks to its success in classification               Table 3: Experimental settings overview.
tasks (Zhang and Zhou, 2007). We also ex-
periment with multi-class SVMs, logistic re-
gression, and neural networks. Regarding the                 As for the text representations, we consider
latter, we experiment with a number of archi-              TF–IDF vectors of both character 3-grams and
tectures with two and three hidden layers. Fi-             word 1-grams (no higher n values are consid-
nally, we experiment with a FastText classi-               ered due to the corpus dimensions). For pre-
fier (Joulin et al., 2017). Table 3 summarizes             processing, we employ the spacy Italian tok-
the explored configurations.3                              enizer4 and casefold the texts. We also explore
                                                           with dense representations, derived from the
    2
      The corpus is available at https://zenodo.org/       TF–IDF vectors, by means of both LDA (Hoff-
record/4022318.
    3
      The code is available at https://github.com/         man et al., 2010) and LSA (Halko et al., 2011).
TinfFoil/AriEmozione. We used Sklearn for the
kNN, SVM, and logistic regression models; Keras            org, https://keras.io/, and https://github.com/
for the neural networks, and the Facebook-provided         facebookresearch/fastText).
library for FastText (cf.      https://scikit-learn.          4
                                                                https://spacy.io/models/it
                                                                     ammirazione
    model               10-fold CV    test
      representation




                                                                                                                    tristezza
                         F1   Acc   F1 Acc
    kNN




                                                                                                           rabbia
                                                                                   amore

                                                                                           gioia

                                                                                                   paura
      char 3-grams      0.38 38.51 0.35 35.15
      words             0.36 36.08 0.35 34.73
      LDA char          0.30 29.97 0.31 30.54
                                                        ammirazione 0.37 0.03 0.18 0.07 0.11 0.06
    SVM–RBF
                                                        amore       0.03 0.43 0.13 0.00 0.09 0.17
      char 3-grams      0.44 43.70 0.43 43.00
                                                        gioia       0.27 0.16 0.31 0.20 0.09 0.07
      words             0.42 42.00 0.44 44.00
                                                        paura       0.10 0.03 0.00 0.40 0.02 0.07
      LDA char          0.28 28.00 0.30 30.00
                                                        rabbia      0.20 0.14 0.03 0.13 0.64 0.17
    Log reg
                                                        tristezza   0.17 0.14 0.13 0.07 0.19 0.48
      char 3-grams      0.44 45.57 0.42 43.10
      words             0.41 43.20 0.41 43.10
      LDA char          0.28 30.63 0.29 30.96       Table 5: Confusion matrix for the 2-layers neu-
    2-layers NN                                     ral network with TF-IDF character 3-grams.
      char 3-grams      0.42 43.61 0.47 46.86
      words             0.42 42.91 0.43 43.10
      LDA char          0.27 29.56 0.27 31.80       for FastText, on which we test with and with-
    3-layers NN
      char 3-grams      0.49 41.86 0.40 41.84       out pre-trained embeddings. Notice that we
      words             0.47 42.60 0.40 41.84       are not interested in combining features, but
      LDA char          0.26 31.41 0.30 31.80
    FastText
                                                    in observing their performance in isolation.
      char 3-grams      0.43 45.00 0.41 42.37          The most promising representation on cross-
      pre-trained chars 0.43 47.00 0.41 41.00       validation appears to be the simple charac-
      words             0.42 42.56 0.39 44.07
      pre-trained words 0.38 41.00 0.40 42.00       ter 3-grams, with which we obtained the best
                                                    results across all models; although it also
Table 4:     F1 and accuracy on cross-              features the highest variability across folds.
validation held-out test for some of the            Among all 3-gram derived representations,
model/representation combinations.                  LDA consistently obtained the worst results
                                                    across all models. Still, it is more stable across
                                                    folds than the sparse 3-gram representation.
In both cases, we target reductions to 16, 32,
                                                    As for fastText, with the same epoch num-
and 64 dimensions. As for embeddings, we
                                                    ber and learning rate, the character 3-gram
adopted the pre-trained 300-dimensional Ital-
                                                    vectors always achieved much higher accuracy
ian vectors of FastText (Joulin et al., 2017),
                                                    than the word vectors.
and tried with character 3-grams and words.
                                                       Similar patterns are observed when project-
4   Experiments                                     ing to the unseen test set. The character 3-
                                                    grams in general hold the best performance,
We conducted several experiments to find the        while the 3-gram LDA tends to remain the
best combination of parameters and represen-        worst in spite of the model used. This be-
tations. Given the amount of instances avail-       havior does not hold in all cases. For instance,
able, we merged the training and development        the logistic regression model achieves F1 =0.44
partitions and performed 10-fold cross valida-      on cross-validation, but drops to 0.42 on test.
tion. As standard, the test partition was left      This might be the result of over-fitting.
aside and only one prediction was carried out          It is worth noting that all models tend to
on it, after identifying the best configurations.   confuse rabbia and tristezza. Table 5 shows
   We evaluate our models on the basis of accu-     the confusion matrix for the best model on
racy and weighted macro-averaged F1 measure         test. These two emotions get confused be-
to account for the class imbalance. Table 4         tween each other on an average of 18% of
shows the results obtained with some inter-         the cases. The classifiers tend to confuse
esting configurations and representations both      ammirazione for gioia as well, which is un-
for the cross-validation and on the test set.5      derstandable given their semantic closeness.
Character and word n-grams TF-IDF, LSA,
and LDA were tested with all models except          5    Related Work
   5
     The full batch of results is available at      Building on the numerous pre-existing stud-
https://docs.google.com/spreadsheets/d/
1Ztjry2mJs6ufCZM1O5CQRyZ8pA5YDnToN0h0NGX1nW0/       ies focusing on sentiment analysis (Ain et al.,
edit?usp=sharing                                    2017; Shi et al., 2019), some researchers have
been seeking to dig deeper, towards multi-class     tristezza, which tend to be confused with
emotion analysis. Most of the work thus far         each other, followed by ammirazione, which
has focused on social media (e.g. Twitter).         is often confused by gioia. In order to fos-
Bouazizi and Ohtsuki (2016) built a classi-         ter the research on this topic, we release the
fier for seven emotions: happiness, sadness,        AriEmozione 1.0 corpus to the community (cf.
anger, love, hate, sarcasm and neutral; i.e.        footnote 2).
an overlap of five classes with respect to the         As for the future work, we intend to in-
ones in ariEmozione. In contrast to our exper-      crease the size of the AriEmozione 1.0 corpus
iments, they focused on exploiting the polarity     by means of active learning (Yang et al., 2009).
of the words from each instance to be fed to a      Once a larger data volume is produced, we
random forest classifier.                           plan to explore with models to identify the
   Balabantaray et al. (2012) tried to distin-      emotion at the aria rather than at the verse
guish among happy, sad, anger, disgust,             level. Following the theory of emotion pro-
fear and surprise using WordNet Af-                 posed by Plutchik (1980), we could identify
fect (Valitutti et al., 2004). Given that no        the emotion of a whole aria by combining the
Word-net-Affect is currently available for Ital-    emotions at the verse level, and then con-
ian, such an approach is unfeasible.                duct experiments to verify which granularity
   Promising work has been carried out on           is more adequate as a single emotion unit. In
news articles (Ye et al., 2012), news head-         order to address the issue of emotional poly-
lines (Strapparava and Mihalcea, 2007) and          semy and ambiguity of aria verses, we aim at
children’s narrative (Alm et al., 2005). While      producing explainable models by highlighting
a lexical-based approach is the most frequent       the specific fragments expressing the emotion.
to determine the binary positive vs nega-              Another interesting alternative is the one
tive classification, Strapparava and Mihal-         highlighted by Zhao and Ma (2019), who
cea (2007) combined a high-dimensional word         adopted an efficient meta-learning approach
space produced from word TF-IDF vectors             to augment the learning ability of emotion
with a set of seed words to predict the va-         distribution; i.e. the intensity values of a
lence of a text exploiting the syntagmatic re-      set of emotions within a single sentence,
lations between words. A bottom-up semantic         when the training dataset is small, as in the
approach has also been proposed (Seal et al.,       AriEmozione 1.0 corpus.
2020).
   To the best of our knowledge, no work in the
                                                    Acknowledgments
field of either emotion or sentiment analysis       This research is carried out in the frame-
has been performed on operas.                       work of CRICC: Centro di Ricerca per
                                                    l’interazione con le Industrie Culturali e Cre-
6   Conclusions and Future Work                     ative dell’Università di Bologna; a POR-FESR
                                                    2014-2020 Regione Emilia-Romagna project
We addressed the novel problem of emotion
                                                    (https://site.unibo.it/cricc).
classification of opera arias at the verse level.
                                                       We thank Ilaria Gozzi and Marco Schillaci,
The task is interesting because of the lack of
                                                    students at Università di Bologna, for their
automated tools for the analysis of operas and
                                                    support in the manual annotation of the
challenging due to both the language used in
                                                    AriEmozione 1.0 corpus.
17th- and 18th-century lyrics and the com-
plexity to produce the necessary amount of
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