Deep Learning for Emoji-Enhanced Emotion Detection
Deep Learning for Emoji-Enhanced Emotion Detection
*Correspondence:
[Link]@[Link]
Abstract
1
Symbiosis Institute The task of emotion detection in online social communication has been explored
of Technology, Symbiosis extensively. However, these studies solely focus on textual cues. Nowadays, emojis
International (Deemed have become increasingly popular, serving as a visual means to express emotions
University), Lavale, Maharashtra
412115, India and ideas succinctly. These emojis can be used supportively or contrastively, even
2
Symbiosis Centre for Applied sarcastically, adding complexity to emotional interpretation. Therefore, incorporating
Artificial Intelligence, Symbiosis emoji analysis is crucial for accurately extracting insights from social media content
International (Deemed
University), Lavale, Maharashtra to support decision-making. This paper aims to investigate to what extent the usage
412115, India of emojis can contribute to the automated detection of emotions in text messages
3
Peoples’ Friendship University with a focus on online social communication. We propose an emoji-aware hybrid deep
of Russia, RUDN University,
Miklukho‑Maklaya Str.6, Moscow, learning framework for multimodal emotion detection. The proposed framework lever-
Russian Federation 117198, ages the feature-level fusion of textual and emoji representations, incorporating con-
Russia ventional and recurrent neural networks, to learn the fused modalities. The proposed
approach was extensively evaluated on the GoEmotions dataset with different perfor-
mance metrics. The experimental results indicate that emoji features can significantly
improve emotion classification accuracy, highlighting their potential for enriching
emotion understanding in online social communication.
Keywords: Multimodal, Fusion, Emoji, Text-based emotion detection, Deep learning,
Early fusion
Introduction
The era of Web 4.0, a symbiotic or mobile web, symbolises the advancement of inter-
net technologies to their next stage. This advancement will have a symbiotic relationship
between humans and machines, where machines will learn from human interactions
and help humans make decisions. The Internet has become an integral part of human
life, where people generate social content by communicating through social media sites
and reviews by sharing experiences and opinions on topics of interest. Likewise, with the
advent of Artificial Intelligence (AI), people interact with intelligent dialogue machines
in conversational AI systems. Understanding the sentiments and emotions behind this
massive amount of online information has become a necessity. Emotional expressions
and detection have become crucial parts of human–machine interaction [1] People
© The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 Inter-
national License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you
give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified
the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The
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credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by
statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of
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Kusal et al. Journal of Big Data (2025) 12:32 Page 2 of 25
express deep and complex emotions with a handful of words, and it has remained a chal-
lenge for machines to identify emotions and sentiments.
Human communication involves a variety of senses or modalities. These modalities
work in concert to clarify concepts and emphasize ideas in discussions by resolving
ambiguity. Similarly, nowadays, people are using various modalities in digital communi-
cations. People have adopted diversity in writing styles when it comes to communication
with Individuals. One of the popular writing styles people favour these days is emojis
in their interactions. The Oxford Dictionary states [2],” Emoji is a small digital image or
icon used to express an idea or emotion in electronic communication”. The word “emoji”
is borrowed from the Japanese language, and it is partitioned as” e”, meaning”picture”,
and”moji” meaning” letter or character”. Emojis consist of smilies and hearts and are
essentially the subsequent natural development of emoticons such as:) And:D. These
days, emoticon means objects represented by standard character sequences, and emoji
means self-reported labels as a piece of visual information users provide to express emo-
tions in textual interactions to improve interpretability, particularly in short, complex
interactions. Emojis can be found in various genres, such as smiles and people, animals
and nature, food and drinks, travel and places, activities and objects. There are thou-
sands upon thousands of emojis, each with a distinct meaning. This visual language is
currently used as the de facto standard for online communication and can be found on
Facebook, Instagram, WhatsApp, Twitter, and other major websites.
This visual information [2] in written text can express affective states, making it an
appropriate means of expressing sentiment and emotion. These emojis and the text
represent the user’s emotional state more faithfully. Analysing the text without emojis
would lead to the loss of important information that conveys people’s feelings or clari-
fies the meaning of the text. In some instances, such as sarcastic phrases [3] a user may
convey positive emotions in the text, but by utilising emoticons or emojis, they may con-
vey negative emotions. In these situations, emojis might assist in determining the user’s
actual feelings. Emojis and emoticons are visual cues that aid in understanding natural
language. For example, I’m satisfied with the service!
In contrast, emojis are also not considered a direct expression of the emotions. Emojis
can have several meanings based on the context and other emojis since they are defined
without precise semantics [4]. So, text and emojis can play a complementary role in text-
based emotion detection to comprehend people’s emotions. Table 1 presents the sample
text along with the accurate emotion label, the text emotion label, and the emoji emotion
label. Despite their prevalence as language form, emojis and their underlying semantics
have not been widely studied from a natural language processing (NLP) perspective.
The complementary role of text and emojis is not explored in-depth by researchers who
have combined features of text and emojis. So, in this work, the authors propose treating
emojis as a new modality with text to enhance emotion detection. The text with emojis
could accurately communicate the genuine feelings or emotions of the people they are
trying to express.
The usage of deep learning techniques has increased with the introduction of big data
[5]. Specifically, in sentiment analysis and emotion detection research, deep learning
techniques have played significant roles. Deep learning techniques improve accuracy
and performance by automatically learning and extracting information. Techniques like
Kusal et al. Journal of Big Data (2025) 12:32 Page 3 of 25
Table 1 Sample Sentences with emotion label of text from the dataset, emotion label of emoji and
valid sentence label
Convolutional neural network (CNN), Recurrent Neural Networks (RNN), Long Short-
Term Memory (LSTM), Gated Recurrent Units (GRU), and their bi-directional variants,
transformer-based models like BERT have proved highly effective in natural language
processing tasks such as sentiment analysis, emotion detection. Advanced deep learn-
ing techniques [6] such as Generative Adversarial Net- works (GAN), Autoencoder (AE),
Graph Neural Networks and Attention mechanisms are progressively used in NLP tasks.
Emojis embedded in the text can help to recognize feelings or emotions; this paper
aims to identify emotions using deep learning techniques from text-based online com-
munication with emojis. This study makes comprehensive use of emojis in text, as well
as the relation between text and emojis. A multimodal deep learning model based on
convolutional and recurrent networks with emojis is proposed for emotion detection in
text-based online communication. Therefore, this multimodal model we develop must
determine which underlying emotion class the input corresponds to given one or more
input modalities. The authors used an emoji-text integrated GoEmotions dataset to pro-
pose a multimodal deep-learning model for better emotion detection. The main contri-
butions of this paper are summarized as follows:
The remainder of this paper is organized as follows. Sect. "Related Work" introduces
the related work on multimodal fusion, unimodal and multimodal emotion detection,
discussing deep learning-based techniques in emotion detection. Sect. "Multimodal
Fusion" provides an overview of the dataset. A detailed explanation of the emoji-aware
proposed framework is found in Sect. "Early Fusion". Sect. "Late Fusion" provides a
detailed description of the experimental setup and the analysis of the results obtained
from the GoEmotions dataset. Sect. "Intermediate Fusion" provides concluding remarks
and presents the future research directions.
Related work
Emotion detection has become increasingly popular in the academic and research com-
munities recently. There are various ways to detect human emotions, such as speech and
facial emotion recognition. Similarly, through EEG signals, emotions can be detected.
However, text-based emotion detection needs to be explored considering the latest
developments in online text communication and the progress to increasing the emo-
tional intelligence of human–computer interaction. As people are using multiple visual
information such as emojis, emotion recognition from text and emojis needs to be stud-
ied. This section surveys literature from three perspectives: (1) Multimodal Fusion (2)
Unimodal text-based emotion detection, (3) Multimodal Emotion detection using text
and emojis.
Multimodal fusion
In today’s online communication era, multiple modes are used to communicate and
present ideas and information. Information is disseminated through written text, audio,
and visuals, including images, videos, and emojis. Social networking sites are account-
able for the continuous increase in the amount of information offered in visual forms.
The potential for communication that visual representation offers is diverse. According
to [14], the world as it is presented differs from the world as it is narrated or written.
The term”multimodality” describes the presentation of information by combining or’in
a sense fusing’ many media formats. This fused representation of different media like
text and visual or text and audio helps users to describe and understand the context in
a profound manner. Multimodality in natural language processing tasks has remained
in focus in recent years in the form of different modalities. Tasks include caption gen-
eration, speech recognition, sentiment analysis, and emotion recognition, where visual
and audio with text modalities have been used. A summary of various representative
multimodality-based NLP task works is provided in Table 2. The authors analyzed these
works based on the modalities used, the kind of fusion, the approach employed, and the
tasks for which it is utilized. Figure 1 shows the basic outline of the multimodal system.
The process of integrating or fusing data from two or more modalities to make a predic-
tion, classification or regression is known as fusion in multimodality. The multimodal
data fusion process is characterized by the level at which the fusion of input modalities
occurs in the network, like early fusion, late fusion, and intermediate fusion. Figure 2
presents the overview of the early and late fusion systems.
Kusal et al. Journal of Big Data (2025) 12:32 Page 5 of 25
Table 2 Literature survey based on types of modalities used, fusion types used, and type task
performed using multimodal fusion
References Type of modalities Fusion types Technique Task
[7] Visual, text, acoustic Early fusion/cross- Deep Learning—Encoder Sentiment analysis
modal with an attention mechanism
[8] Visual, text, acoustic Early fusion Deep learning—LSTM, BERT, Sentiment analysis
CNN
[9] Text, acoustic Late fusion Deep Learning—Attention Emotion recognition
with auto- encoder, Bi-LSTM
[10] Visual, text, emoji, Early fusion Deep Learning—Bi-GRU, Sarcasm detection
acoustic Gated attention mechanism
[11] Image, text Early fusion Deep Learning—RNN, Pre- Machine translation
trained CNN
[12] Text, emoji Late fusion Deep learning—Bi− GRU Emotion detection
with attention
[12] Text, emoji Late fusion SVM, Deep learning—Bi- Sentiment analysis
LSTM, CNN
[13] Text, acoustic Late fusion Deep learning—Bi-RNN, Self- Emotion recognition
Attention, BERT
[2] Text, emoji Early fusion Deep Learning—FastText, Emotion classification
Pre-trained FastText
Early fusion
It is the traditional way of fusion, also called a feature or data-level fusion. In early
fusion, data fusing involves concatenating original data or extracted features, i.e., data
transformed into features at the input level before input to a unified single model that
accepts all modalities in one model. Data fusion takes place in many ways, typically
pooling or concatenation. A Unified model can be any machine learning algorithm
such as Random forest, SVM or deep learning model like CNN, RNN, etc. In early
fusion, to accommodate multiple data modalities into a unified model, data trans-
formation into a single feature vector is essential [15]. Proposed early data fusion by
concatenating textual, acoustic and visual features in the multimodal stream for senti-
ment analysis.
Kusal et al. Journal of Big Data (2025) 12:32 Page 6 of 25
Late fusion
Late fusion is also termed decision-level fusion as it aggregates predictions or results at
the decision level. In late fusion, a number of algorithmic models are trained, typically
one model per modality type. By combining the decisions from multiple models into a
unified decision, a conclusion can be drawn. An ensemble approach inspires late fusion.
In the ensemble approach, multiple models are trained on the same data, whereas in
late fusion, multiple models are trained on different data. In late fusion, models must
attempt to predict the same outcome. In late fusion, the number of models to be trained
depends on the number of data modalities to be fused. To fuse the decisions from dif-
ferent models, different rules are used, such as the Bayes model, max-fusion, average
fusion, etc. Late fusion is simpler than early fusion as compared from an architecture
point of view. Data from different modalities are handled by multiple models individu-
ally and dealt with independently, so errors are also handled by models independently or
uncorrelated, so late fusion gives good performance compared to early fusion [16]. Used
an attention-based late fusion mechanism for task adaptation in natural language under-
standing. The authors developed a late fusion method capable of aggregating representa-
tion from intermediate layers of the pre-trained BERT model to adapt to a downstream
NLU task.
Intermediate fusion
It is also called hybrid or joint fusion. In intermediate fusion, multiple models are trained
but in a stepwise manner. The output of some models with input features from different
modalities is given to subsequent models for outcome. Similar to early fusion, interac-
tion effects between the parameters take place. Models are trained in a stepwise fash-
ion so loss from the second model can be propagated back to the first model, updating
weights for both models. Intermediate fusion is based on deep neural networks, allowing
the most flexible fusion of features at different depths of model training. So, it is built
in a very conscientious manner. Intermediate fusion provides significantly improved
Kusal et al. Journal of Big Data (2025) 12:32 Page 7 of 25
analyze emotions. the authors used the Sina social net- working site for Chinese micro-
blog reviews. To obtain emoji embeddings, the emoji vectorization method was used
in which the authors applied multidimensional emotion and emotional value to trans-
form emojis into equivalent emoji vectors using word2vec. The text was also converted
to vectors using word2vec. Linear SVM, random forest and LSTM models were evalu-
ated on the dataset using macro precision, recall and F1-Score [12]. Presented a SEER
model to capture the emotions of words and used emoticons to enhance the emotion
detection task. The authors used the Bi-GRU model to capture semantic information,
whereas statistical analysis of emoticons from datasets was used to extract emotional
information from emoticons. Different machine learning and deep learning models,
including SVM, GRU, LSTM and its bi-directional variants and CNN-Bi-LSTM, were
assessed on NLPCC2013 and NLPCC2014 datasets using precision, recall and F1-Score.
The authors [22] curated a large dataset of 58 k English Reddit comments with twenty-
eight emotion classes. It is an emoji-integrated text dataset annotated using principal
preserved component analysis (PCA). The authors used transfer learning based on the
BERT model and evaluated the F1- score, precision, and recall along with Bi-LSTM as
the baseline model [23]. Presents emojis that could contribute to automating sentiment
analysis. The authors created an Arabic-language Twitter tweet dataset. In order to inte-
grate text and emojis at the feature, score, decision, and hybrid levels, the authors sug-
gested early and late fusion. For text feature extraction, TF-IDF, CBOW and Skip-gram
approaches were employed, whereas emoji frequency, lexicon-based, emoji CBOW and
emoji skip-gram methods were utilized for emoji extraction. These features were classi-
fied using SVC and LR and evaluated using precision, recall, F1-score and accuracy [24].
Developed a speech act classification to determine the intent of Twitter. The authors
generated a dataset from the speech act on Twitter and named it EmoTA. The dyadic
attention mechanism was introduced to fuse the modalities in the intra-model and inter-
model attention ways. The authors used BERT for text feature extraction and emoji2Vec
representation for emoji feature extraction. Bi-directional LSTM was used in a multi-
tasking framework using a fully shared and shared private model. When this multitask,
framework was evaluated based on accuracy and F1-score, the multimodal results out-
performed the unimodal ones.
Dataset
In order to train the predictive models in supervised machine learning algorithms,
labelled datasets are needed. A significant amount of human effort is needed to cresate
annotated or labelled datasets. One of the significant challenges in multimodality is
choosing a multimodal dataset. The authors surveyed three datasets suitable for mul-
timodal analysis with text and emojis. The authors studied GoEmotions [22], EmoCon-
text [25], and TweetEval [26] datasets curated from social media sites such as Twitter or
Reddit. After thoroughly looking at the datasets based on the number of records, num-
ber of emotions, and sources from where they were curated, the authors preferred to
go with the GoEmotions. The GoEmotions dataset offers the most comprehensive cov-
erage of expressed emotions and minimum overlap between emotions, so the authors
preferred it. It was built on 27 emotion labels with neutral categories. These 28 emotion
labels from the dataset are easily mapped further to the Ekman model of emotions. This
Kusal et al. Journal of Big Data (2025) 12:32 Page 9 of 25
collection of 58 K records has been compiled from Reddit comments. It is available for
public use*. Data was gathered from the platform from Reddit’s founding in 2005 until
January 2019.
The dataset contains the records with only text and emojis. Some records include sim-
ple text, text with one emoji, and text with more than two emojis. Although data con-
tains two modalities, text and emojis, the dataset is annotated only for text information.
It is observed from Fig. 3 that there is a significant discrepancy in terms of emotion fre-
quencies. For example, adoration is 30 times more frequent than grief. Figure 3 presents
the emotion categories with the number of samples. we have analyzed the total number
of entries in the training, validation, and testing sets that include emojis incorporated
in the textual description. It was observed that around 3.51% of the samples had emojis.
Proposed methodology
This section outlines the overall architecture for the multimodal framework using text
and emojis and implementation details. Figure 4 displays the overall architectural dia-
gram of the suggested system. Our approach is based on extracting features from two
distinct modalities: text and emojis. They are described as follows:
Fig. 3 Statistics on the total number of samples with single and multiple labels for each emotion category
Kusal et al. Journal of Big Data (2025) 12:32 Page 10 of 25
ling. Textual data is pre-processed with data cleaning, normalization and vectoriza-
tion.
(a) Data Cleaning: We have performed the following stages to remove noise and
inconsistencies from the text data, typically including:
(b) Tokenization/Segmentation: In this step, the text is divided into distinct chunks
known as tokens, which are usually words or morphemes. As a result, the original
text is represented by a series of tokens that may be further processed and analyzed.
(c) Normalization: This step improves consistency and facilitates analysis by reducing
morphological variants of words to their regular forms. Stemming and lemmati-
zation are two typical methods of normalizing. We have applied lemmatization to
identify the grammatical root of a word (lemma) based on its context and linguis-
tics.
2. Textual Feature Extraction—Then, the second step is to extract the features from
pre-processed textual data. Our approach leverages pre-trained NNLM embeddings
to represent words as vectors within a d-dimensional space. These embeddings,
trained on the GoEmotion corpus, provide a sophisticated comprehension of word
Kusal et al. Journal of Big Data (2025) 12:32 Page 11 of 25
meanings and emotions. The NNLM algorithm [27],) introduced the idea of train-
ing word embeddings in a statistical neural network language model (NNLM). This
novel methodology aimed to predict the subsequent word in a sequence by lever-
aging the previous words, effectively capturing the semantic and syntactic connec-
tions among them. NNLM embeddings, context-based representations, are token-
based text embeddings trained on diverse English Google News 200B corpus. In this,
each word (token) is mapped to a 128-dimension fixed-length vector representing its
meaning and relationships with other words, which means capturing semantic and
syntactic relationships between words, even for out-of-vocabulary (OOV) words.
• The first step is One-Hot Encoding, where each word from preprocessed input w ∈ V
is mapped to a one-hot vector of dimension |V | and given by equation 1:
where:
ℎwi: 1 if and only if i = w and 0 otherwise
These vectors are sparse and computationally expensive due to their high
dimensionality.
Emoji modality
1. Emoji Processing—We have used emoji, a Python-based library for separating the
visual representation of an emoji, to extract the emoji features from the input text.
There are 1816 distinct kinds of emojis accessible in all.
2. Emoji Feature Extraction—Then, we employed Emoji2Vec, a pre-trained word
embedding model specifically designed for emojis for emoji representation. This
Kusal et al. Journal of Big Data (2025) 12:32 Page 12 of 25
Fusion of modalities
Early fusion or feature fusion approach is applied to combine the features from text and
emojis. This approach merges information from different modalities by directly concat-
enating their extracted features. This generates an augmented feature vector in a higher-
dimensional space, encompassing the combined information. The extracted feature
vectors or embeddings of text modality and emoji modality are concatenated. It employs
a simple feature-level fusion approach by concatenating the extracted textual and emoji
features. Mathematically, let Ŵ = (f1 , f2 , . . . , fd ) be the textual feature vector with d
dimensions, represented in Rd where d = 128, E = (e1, e2, . . . , en) be the emoji feature
vector with n dimensions, represented in Rn where n = 300. The combined feature vector
C is then obtained by directly concatenating these two vectors:
C = f1 , f2 , ..., fd , e1 , e2 , ..., en .
Model architecture
The combined feature vector C is made to pass through the modality encoder. The pro-
posed multimodal emotion detection using a hybrid convolutional-recurrent model is
shown in Fig. 5. In Fig. 5, red circles show the emoji representations, while green circles
show textual representations. Similarly, the circle shape represents the recurrent com-
ponent, and the square shape represents the convolutional component in the modality
encoder of the system. The modality encoder is a neural network which predicts the final
class label using the SoftMax function, as it is a multiclass classification detection prob-
lem. The Convolutional neural network layers are used for local feature extraction to
identify the patterns that might be indicative of specific emotions and, similarly, recur-
rent layers to capture long-range dependencies and con- textual information from the
sequence of text with emojis. Given an input text t with emojis, the proposed multimodal
model calculates a probability for each 28-emotion label using a series of layers. These
layers utilize the pre-trained word embeddings, where NNLM pre-trained embeddings
Kusal et al. Journal of Big Data (2025) 12:32 Page 13 of 25
are used to convert each word in the phrase into a high-dimensional vector representa-
tion, and Emoji2Vec pre-trained embeddings are used in the case of emojis. Combined
vectors capture semantic and contextual information about the word and emojis, allow-
ing the model to learn essential features from the entire sequence. The authors experi-
mented with the combined architecture of CNN- LSTM and CNN-Bi-LSTM. Similarly,
the authors have used LSTM and bidirectional LSTMs (Bi-LSTMs). We adopted LSTM
to understand the long-term dependencies with context and a Bi-LSTM network to cap-
ture the sequence’s forward and backward context. LSTM, CNN-LSTM, BiLSTM, and
CNN-BiLSTM models are proficient at catching sequential and contextual dependen-
cies in data. So, when emojis and text are combined in an early approach, these models
learn combined embeddings, allowing them to comprehend emoji meanings based on
the surrounding textual context. Also, bidirectional models can process input from both
directions, forward and back- ward, aiding the model in contextualizing emojis more
effectively in broader sentences. CNN can capture local patterns and relationships and
inherently shift-invariants. So, combining the characteristics of convolutional features
with sequential modeling will enhance the extraction of local patterns, which may dis-
ambiguate emoji meanings to improve understanding of multimodal emotion detection.
ci = f F ∗ e(i:i+s−1) + b (2)
where:
f: Non-linear ReLU function.
b: Bias-vector.
Each filter, in the convolution operation, slides across all possible windows
of features in the sequence. This process generates a feature map, denoted as
cm = [cm1 , cm2 , . . . , cm(n−s+1) ], where n is the sentence length and s is the filter size. In
the first stage, if k filters are used, this operation creates k distinct feature maps. In this
specific case, the convolutional layer employs 128 filters, resulting in the generation of
128 distinct feature maps. After the convolutional layer, a max pooling layer is applied to
get 128 feature values corresponding to 128 feature maps. Then, these feature values are
provided to the recurrent layer sequentially.
cm1, cm2, ..., cmk, which are sequentially sent to the recurrent layer. For each combined
vector (denoted by cmi), LSTM computes only using one hidden state. At the same time,
the Bi-LSTM computes it’s forward and backward hidden states, denoted by ℎi−1 and
ℎi+1, respectively. These are obtained using the following equations Equation 3 and 4:
Forward hidden state:
The final hidden state matrix for the feature vector representation of user input, ℎu,
is then constructed by concatenating the forward and backward hidden states for each
word in the sequence and is expressed by Eq. 5:
Final hidden state matrix:
Here, nc is the sequence length, dl is the number of hidden units in each LSTM
layer, and ℎu is the concatenation of ℎif and ℎib. This final matrix, Hu, captures the
Kusal et al. Journal of Big Data (2025) 12:32 Page 15 of 25
contextualized representation of the entire user input, serving as the input for subse-
quent processing. At each time step t, the recurrent network takes the input cmt and the
output of the previous step ℎt−1. It then creates the current output ℎt by applying a linear
transformation following a non-linear activation function and expressed by Eqs. 6 and 7.
yt = tanh Why ∗ ht + by (7)
where:
ℎt: hidden state in time t.
cmt:input feature vector from the convolutional layer in time t.
yt: output in time t.
Wcmℎ:Weight matrix for input to the hidden connection.
Wℎℎ:Weight matrix for hidden-to-hidden connection.
Wℎy:Weight matrix for hidden-to-output connection.
b: Bias vector for the hidden layer.
by: Bias vector for the output layer.
The final classification stage takes the output from the recurrent layer as input. In
simpler terms, the SoftMax function takes the recurrent layer’s output (Eq. 8)(possibly
containing high-dimensional representations) and transforms it into a probability dis-
tribution over the N possible output labels (emotions) for a given text input. And output
layer is defined as follows –
where:
P (e): the probability distribution over emotion classes.
Experiments
Evaluation measures
In order to evaluate proposed multimodal system, we adopted accuracy, weighted pre-
cision, weighted recall, and weighted F1 score. Evaluating the performance of emo-
tion detection models presents a challenge as an intrinsic imbalance in emotion class
distributions within most real-world benchmark datasets. Accuracy alone is a biased
measure in imbalanced classification problems. No single metric can definitively cap-
ture the model’s effectiveness in such scenarios. Therefore, to gain a more comprehen-
sive understanding of the model’s performance, we have also used a classification report
and confusion matrix to analyze the emotion class-wise performance as it is a multiclass
classification problem. Similarly, accuracy and loss curves against time were used to
show the performance of the proposed system. Distinct colors are utilized to depict vari-
ous models in curves, while the continuous line signifies the accuracy and loss during
training. On the other hand, dashed lines indicate the accuracy and loss of the validation.
Kusal et al. Journal of Big Data (2025) 12:32 Page 16 of 25
Algorithm 1 Algorithm
Experimental settings
The GoEmotion dataset was divided randomly into two parts of 80% 20% split for train
and test sets, respectively. And again, from the training set, 20% was used as a valida-
tion set. The statistics of the training, validation, and test set are shown in Table 3. For
single modality and multimodal classification, LSTM, Bi-LSTM and Hybrid architec-
tures of CNN-LSTM and CNN-Bi-LSTM were adopted. To optimize performance, the
Kusal et al. Journal of Big Data (2025) 12:32 Page 17 of 25
Convolutional parameters
Embeddings NNLM embeddings,
Emoji2Vec embeddings
Filter size 128
Kernel size 5
Pooling Max = 2
Stride Default = 1
Padding Same
Activation function ReLU
Recurrent parameters
Hidden units 64
Number of layers 1
Epochs 20
Activation functions SoftMax
Loss function Categorical Cross Entropy
Optimizer Adam optimizer
Learning rate 0.001
Batch size 512
Table 4 Results of proposed multimodal models in terms of accuracy, precision, recall and weighted F1-score
Model Only text Only emoji Combined (text + emoji)
Accuracy Precision recall F1-score Accuracy Precision recall F1-score Accuracy Precision recall F1-score
Training validation Training validation Training validation
LSTM 60.82 57.34 53.81 57.57 54.47 43.81 35.91 36.63 35.91 32.31 75.94 72.01 69.91 72.24 70.64
CNN-LSTM 67.32 62.00 60.83 63.84 61.73 51.93 37.72 46.68 37.72 38.94 72.45 67.70 65.32 67.60 65.96
Bi-LSTM 69.64 61.80 68.37 70.67 68.80 50.37 36.95 42.18 36.95 35.63 77.03 72.15 69.61 71.97 70.08
CNN-Bi-LSTM 70.28 65.57 68.57 70.62 69.14 53.70 37.99 45.52 36.43 36.96 77.80 73.29 71.01 72.96 71.68
Page 19 of 25
Kusal et al. Journal of Big Data (2025) 12:32 Page 20 of 25
Fig. 6 Accuracy curves and loss curves for proposed multimodal models on the GoEmotions dataset
Table 5 Comparison of SOTA methods with our results on the Empathetic dialogue dataset for
emotion detection
No Reference Deep learning method Performance
metrics
in the matrix represents the frequency of predictions made by the model for a certain
class label, compared to the actual class label in the data. Optimally, the diagonal ele-
ments, which indicate correctly categorized instances, possess greater values, indicat-
ing successful predictions. Whereas off-diagonal elements shows misclassifications. In
Fig. 8, all models shown diagonally high values which means correct predictions of the
models in each emotion class. As the authors can figure out from confusion matrix of
CNN-Bi-LSTM model has shown, “grief ”, “relief ”, “pride”, “nervousness” and “fear” are
Kusal et al. Journal of Big Data (2025) 12:32 Page 21 of 25
Fig. 8 Presents a confusion matrix for (a) LSTM, (b) Bi-LSTM, (c) CNN-LSTM, and (d) CNN-Bi-LSTM models
the emotions that are better predicted. Similarly, class “neutral” has the less number of
correct classifications. There are some emotion class pairs where we could see misclas-
sifications, like in between “neutral and approval”, “neutral” and disapproval”. The less
accuracy for these emotions might indicates a similarity in the words, phrases and emo-
jis used to convey them.
Ablation study
An ablation study is an effective technique used in artificial intelligence to analyse the
specific impacts of various components of a model on its overall performance. It entails
methodically eliminating or altering components of the model and analyzing the impact
of these modifications on its output. To understand the effect of emoji and the effect of
the convolutional component on the proposed model, we perform an ablation study. The
results are shown in Table 5. For the setups, we observe that the best-proposed model
outperformed w/o emoji and the proposed w/o convolutional component.
Kusal et al. Journal of Big Data (2025) 12:32 Page 22 of 25
Impact of emojis
Although our main focus is to study the effect of emojis on emotion detection, from
Tables 4, 6 and 7, We observe that emojis are helpful in improving the performance
of emotion detection. Empirically, we have shown that emoji helps emotion detection
(Table 6). We took some examples from the dataset (Table 7) and off the dataset also,
which are sentences that include emojis to show the effect of emojis. Each example
has an implicit/explicit emotion with emojis. We have included examples in both ways
where emojis are supporting text and where emojis are contrasting the text, such as sar-
castically or ironically. Table 7 shows the sample text with an emoji with the predicted
label. Table 7 shows the predicted label for examples and whether the proposed model
predicted the label correctly or not by human evaluation. Interestingly, the predictions
made by the model were correct in many sarcastic cases, but in some cases, they were
incorrect. We observe that emoji’s emotion plays an important role in emotion detec-
tion. In the example,”I am happy with service! ”, the emotion displayed by the emojis is
negative, whereas the text is positive. This aids the model in understanding the contra-
distinction between the emotion displayed by the text and the emoji. Thus, it correctly
Kusal et al. Journal of Big Data (2025) 12:32 Page 23 of 25
interprets that the example is sarcastic. In the example,”I’m scared to even ask my mom;
I might get yelled at ”, the model fails to comprehend the precise distinction between
the text as the emojis do not provide any further distinguishable information to the
model about it in training.
The proposed system can be integrated into existing systems or current frameworks
where text and emoji-based emotion detection can be used as a supplemen-tary task.
In chatbots or virtual assistants, the proposed model can be used to detect the emo-
tions of input text and to generate responses empathetically. Emotions such as happi-
ness, confusion, and frustration can be easily recognized by combining text and emoji
cues, and more effective communication can be achieved. Similarly, in recommendation
systems, Community Management Tools, and Customer-Centric Marketing Systems,
the proposed model can provide more nuanced emotion detection by understanding the
emotional tone of emojis with text.
Various fields, including healthcare, e-commerce, and social media, have distinct usage
patterns for emojis. In healthcare, emojis are used to denote symptoms or mental state
through emotions. In e-commerce, emojis are used to indicate product characteristics
or feelings related to product or service use. The proposed model can be trained using
domain-specific datasets, allowing predictions to be customized to the distinct needs of
each domain.
Despite their widespread use, emojis may have variable meanings depending on the
languages and cultures. As per cultures, people use different emojis to convey their
thoughts and emotions. E.g., An emoji , for instance, may mean ”thank you” in one
culture and ”prayer” in another. The proposed model, which utilizes Emoji2Vec embed-
dings to transform emojis into semantic vector spaces depending on their usage in
natural language, enhances its ability to recognize intended meanings across many cul-
tural contexts. Similarly, Cross-linguistic and cultural adaptability can addressed by
training and fine-tuning the proposed model using multilingual datasets. To ensure it
understands cultural and linguistic fineness in emoji use, the proposed model can be
pre-trained on datasets annotated with different languages and then fine-tuned using
domain-specific data, which can further enhance the interpretation of emojis.
Kusal et al. Journal of Big Data (2025) 12:32 Page 24 of 25
Conclusion
This study presents a comprehensive review of work related to emoji-based emotion
and sentiment analysis in online social communication. This work investigates the role
of emojis in emotion detection and multimodality in text-based emotion detection. The
authors explored the potential of multimodal text-emoji fusion for text-based emotion
detection on the GoEmotions dataset using baseline deep neural networks. In the pro-
posed hybrid framework of convolutional and recurrent networks, the authors effec-
tively combined textual and emoji features, achieving superior performance compared
to models relying solely on text. It highlights the significant emotional information
embedded within emojis and their cooperative effect with textual cues. Additionally,
the ablation study provided valuable insights into the contribution of each modality,
revealing the importance of both textual and emoji features for optimal performance.
So, the simplicity of the concatenation of two modalities at the feature level makes it a
straightforward to implement and computationally efficient system. Additionally, com-
bining features from various modalities has been empirically shown to improve predic-
tion performance, leading to its widespread adoption within the research com- munity.
Future research directions include investigating the impact of different emoji embedding
techniques such as transformer-based embeddings can offer robust solutions for disam-
biguating emojis and improving the precision of the system to further enhance emotion
detection accuracy in online social communication. Similarly, the late fusion approach of
modalities could be evaluated to investigate the impact of emojis.
Acknowledgment
This paper has been supported by the RUDN University Scientific Projects Grant System, Project 202235-2-000.
Author contributions
Conceptualization, S.K., S.P., and K.K.; Methodology, S.K., S.P., and K.K.; Software, S.K.; Validation, S.K., S.P., and K.K., formal
analysis, S.K., and S.P.; investigation, S.K., S.P., and K.K; resources, S.K. and S.P.; data curation, S.K., and S.P.; writing—original
draft preparation, S.K.; writing—review and editing, S.P.; visualization, S.K.; supervision, K.K.; project administration, S.P.;
funding acquisition, K.K. All authors have read and agreed to the published version of the manuscript.
Funding
Open access funding provided by Symbiosis International (Deemed University). This work was supported by the
Research Support Fund (RSF) of Symbiosis International (Deemed) University, Pune, India.
Data availability
No datasets were generated or analysed during the current study.
Declarations
Ethics approval and consent to participate
Not applicable.
Competing interests
The authors declare no competing interests.
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Class imbalance in emotion detection datasets poses significant challenges, as models tend to favor the dominant class, thus leading to biased predictions that neglect minority classes. This is evident in the 'neutral' class, which often has a higher number of samples compared to other emotion classes. To mitigate these challenges, techniques such as using precision, recall, and F1-score over accuracy provide a better assessment of model performance in imbalanced scenarios. Additionally, oversampling strategies are employed to balance the dataset by augmenting the number of underrepresented class samples, ensuring that all classes are adequately represented during model training and evaluation .
Visual cues like emojis significantly enhance user understanding in text-based communication by providing an additional layer of emotional context that text alone might lack. Emojis help clarify the tone or intention behind messages, reducing ambiguity and misunderstanding. They can convey emotions such as happiness, confusion, and frustration more directly, thus facilitating more straightforward and effective interaction. In environments such as social media and customer-centric communication, emojis complement written words to create a richer, more nuanced expression of emotions, enabling more accurate sentiment analysis and communication .
Experiments to evaluate the performance of the proposed multimodal emotion detection system involved a thorough analysis using the GoEmotions dataset. The dataset was split into training and test sets, with specific partitions for validation. The model's performance was assessed using measures like accuracy, precision, recall, and F1-score, particularly focusing on handling class imbalance in the dataset. Various architectures, including LSTM, Bi-LSTM, CNN-LSTM, and CNN-Bi-LSTM were tested with different modalities. Among these, the CNN-Bi-LSTM model showed the highest overall performance. The experiments also included visual evaluations using accuracy and loss curves to compare training and validation phases across modalities .
The proposed hybrid framework enhances emotion detection on the GoEmotions dataset by incorporating emojis as an integral modality alongside text. This is achieved through a multimodal fusion approach that combines convolutional and recurrent neural networks, specifically CNN-LSTM models. By treating emojis as an additional feature, the model can extract complementary emotional cues that are not evident in text alone. The incorporation of Emoji2Vec embeddings further enriches the semantic interpretation of emojis, enabling the model to better understand and classify the emotions expressed in online text communications. This results in a more accurate and comprehensive emotion detection system .
The use of emojis in natural language processing tasks enhances emotion detection by serving as a complementary modality alongside text. Emojis provide visual cues that help interpret the actual feelings conveyed in written communication, especially when the text's tone or context is ambiguous. By combining text with emojis, a multimodal approach is developed, which leverages deep learning techniques like CNN and RNN to enrich sentiment analysis and achieve more accurate emotion recognition. This complementary role is particularly highlighted in the proposed emoji-aware multimodal hybrid framework, which effectively combines textual and emoji features, thus improving the precision in emotion detection tasks .
The advantages of using a multimodal approach in text-based emotion detection include enhanced accuracy and depth of emotional understanding. By integrating textual and visual modalities, such as emojis, into a unified framework, multimodal systems can capture a broader range of emotional cues that a singular modality might miss. This approach addresses ambiguities and provides a more robust interpretation of emotions, leveraging the strengths of each modality. The hybrid framework explored in the study demonstrates that combining text and emoji data significantly improves performance metrics like F1-score, precision, and recall, compared to using text alone .
Precision and recall are crucial for evaluating models on unbalanced datasets because they provide insights that accuracy alone cannot. Precision measures the proportion of true positive predictions among all positive predictions made by the model, indicating its accuracy in labeling positive instances. Recall, on the other hand, measures the proportion of true positives out of all actual positives, showing the model's ability to identify all relevant instances within the data. These metrics are especially valuable when dealing with unbalanced datasets, where accuracy might be misleading due to a large number of majority class predictions. Precision and recall offer a more nuanced view of the model's performance, helping identify how well the model handles minority class predictions .
Domain-specific customization can improve the effectiveness of emotion detection models by tailoring the model to recognize unique patterns and nuances present in specific fields, such as healthcare, e-commerce, or social media. By training models on domain-specific datasets, the system can adapt to the particular semantic usages of emojis and textual expressions within each context. For instance, in healthcare, emojis might represent symptoms, while in e-commerce, they might reflect product satisfaction. This customization enables the models to accurately interpret emotions and provide more personalized and relevant outcomes, thereby enhancing their utility and accuracy across different professional environments .
To address cultural variability in emoji interpretation across different linguistic contexts, a cross-linguistic and cultural adaptability approach is proposed. The use of Emoji2Vec embeddings allows the transformation of emojis into semantic vector spaces that vary based on their usage in natural language, accounting for diverse cultural meanings. Additionally, training the proposed model on multilingual datasets with annotations for different languages and fine-tuning it using domain-specific data ensures effective cultural adaptation. This method helps the model understand and interpret emojis' intended meanings across various cultural and linguistic settings, enhancing the model's effectiveness in global applications .
Deep learning techniques significantly improve the performance of emotion detection systems by automatically learning intricate patterns and features embedded in data, which are crucial for recognizing complex emotional states. Techniques such as CNN, RNN, LSTM, and transformer-based models like BERT have shown effectiveness in capturing the nuances of both textual and visual elements like emojis. These methods enhance the accuracy and robustness of predictions by integrating various modalities and leveraging large-scale datasets. For instance, the proposed emoji-aware multimodal framework uses a combination of convolutional and recurrent networks to achieve superior performance in detecting emotions from text-based online communication .