Mithun Das


2024

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Evaluating ChatGPT against Functionality Tests for Hate Speech Detection
Mithun Das | Saurabh Kumar Pandey | Animesh Mukherjee
Proceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation (LREC-COLING 2024)

Large language models like ChatGPT have recently shown a great promise in performing several tasks, including hate speech detection. However, it is crucial to comprehend the limitations of these models to build robust hate speech detection systems. To bridge this gap, our study aims to evaluate the strengths and weaknesses of the ChatGPT model in detecting hate speech at a granular level across 11 languages. Our evaluation employs a series of functionality tests that reveals various intricate failures of the model which the aggregate metrics like macro F1 or accuracy are not able to unfold. In addition, we investigate the influence of complex emotions, such as the use of emojis in hate speech, on the performance of the ChatGPT model. Our analysis highlights the shortcomings of the generative models in detecting certain types of hate speech and highlighting the need for further research and improvements in the workings of these models.

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Low-Resource Counterspeech Generation for Indic Languages: The Case of Bengali and Hindi
Mithun Das | Saurabh Pandey | Shivansh Sethi | Punyajoy Saha | Animesh Mukherjee
Findings of the Association for Computational Linguistics: EACL 2024

With the rise of online abuse, the NLP community has begun investigating the use of neural architectures to generate counterspeech that can “counter” the vicious tone of such abusive speech and dilute/ameliorate their rippling effect over the social network. However, most of the efforts so far have been primarily focused on English. To bridge the gap for low-resource languages such as Bengali and Hindi, we create a benchmark dataset of 5,062 abusive speech/counterspeech pairs, of which 2,460 pairs are in Bengali, and 2,602 pairs are in Hindi. We implement several baseline models considering various interlingual transfer mechanisms with different configurations to generate suitable counterspeech to set up an effective benchmark. We observe that the monolingual setup yields the best performance. Further, using synthetic transfer, language models can generate counterspeech to some extent; specifically, we notice that transferability is better when languages belong to the same language family.

2023

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hate-alert@DravidianLangTech: Multimodal Abusive Language Detection and Sentiment Analysis in Dravidian Languages
Shubhankar Barman | Mithun Das
Proceedings of the Third Workshop on Speech and Language Technologies for Dravidian Languages

The use of abusive language on social media platforms is a prevalent issue that requires effective detection. Researchers actively engage in abusive language detection and sentiment analysis on social media platforms. However, most of the studies are in English. Hence, there is a need to develop models for low-resource languages. Further, the multimodal content in social media platforms is expanding rapidly. Our research aims to address this gap by developing a multimodal abusive language detection and performing sentiment analysis for Tamil and Malayalam, two under-resourced languages, based on the shared task Multimodal Abusive Language Detection and Sentiment Analysis in Dravidian Languages: DravidianLangTech@RANLP 2023”. In our study, we conduct extensive experiments utilizing multiple deep-learning models to detect abusive language in Tamil and perform sentiment analysis in Tamil and Malayalam. For feature extraction, we use the mBERT transformer-based model for texts, the ViT model for images and MFCC for audio. In the abusive language detection task, we achieved a weighted average F1 score of 0.5786, securing the first rank in this task. For sentiment analysis, we achieved a weighted average F1 score of 0.357 for Tamil and 0.233 for Malayalam, ranking first in this task.

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hate-alert@LT-EDI-2023: Hope Speech Detection Using Transformer-Based Models
Mithun Das | Shubhankar Barman | Subhadeep Chatterjee
Proceedings of the Third Workshop on Language Technology for Equality, Diversity and Inclusion

Social media platforms have become integral to our daily lives, facilitating instant sharing of thoughts and ideas. While these platforms often host inspiring, motivational, and positive content, the research community has recognized the significance of such messages by labeling them as “hope speech”. In light of this, we delve into the detection of hope speech on social media platforms. Specifically, we explore various transformer-based model setups for the LT-EDI shared task at RANLP 2023. We observe that the performance of the models varies across languages. Overall, the finetuned m-BERT model showcases the best performance among all the models across languages. Our models secured the first position in Bulgarian and Hindi languages and achieved the third position for the Spanish language in the respective task.

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BanglaAbuseMeme: A Dataset for Bengali Abusive Meme Classification
Mithun Das | Animesh Mukherjee
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing

The dramatic increase in the use of social media platforms for information sharing has also fueled a steep growth in online abuse. A simple yet effective way of abusing individuals or communities is by creating memes, which often integrate an image with a short piece of text layered on top of it. Such harmful elements are in rampant use and are a threat to online safety. Hence it is necessary to develop efficient models to detect and flag abusive memes. The problem becomes more challenging in a low-resource setting (e.g., Bengali memes, i.e., images with Bengali text embedded on it) because of the absence of benchmark datasets on which AI models could be trained. In this paper we bridge this gap by building a Bengali meme dataset. To setup an effective benchmark we implement several baseline models for classifying abusive memes using this dataset. We observe that multimodal models that use both textual and visual information outperform unimodal models. Our best-performing model achieves a macro F1 score of 70.51. Finally, we perform a qualitative error analysis of the misclassified memes of the best-performing text-based, image-based and multimodal models.

2022

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hate-alert@DravidianLangTech-ACL2022: Ensembling Multi-Modalities for Tamil TrollMeme Classification
Mithun Das | Somnath Banerjee | Animesh Mukherjee
Proceedings of the Second Workshop on Speech and Language Technologies for Dravidian Languages

Social media platforms often act as breeding grounds for various forms of trolling or malicious content targeting users or communities. One way of trolling users is by creating memes, which in most cases unites an image with a short piece of text embedded on top of it. The situation is more complex for multilingual(e.g., Tamil) memes due to the lack of benchmark datasets and models. We explore several models to detect Troll memes in Tamil based on the shared task, “Troll Meme Classification in DravidianLangTech2022” at ACL-2022. We observe while the text-based model MURIL performs better for Non-troll meme classification, the image-based model VGG16 performs better for Troll-meme classification. Further fusing these two modalities help us achieve stable outcomes in both classes. Our fusion model achieved a 0.561 weighted average F1 score and ranked second in this task.

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HateCheckHIn: Evaluating Hindi Hate Speech Detection Models
Mithun Das | Punyajoy Saha | Binny Mathew | Animesh Mukherjee
Proceedings of the Thirteenth Language Resources and Evaluation Conference

Due to the sheer volume of online hate, the AI and NLP communities have started building models to detect such hateful content. Recently, multilingual hate is a major emerging challenge for automated detection where code-mixing or more than one language have been used for conversation in social media. Typically, hate speech detection models are evaluated by measuring their performance on the held-out test data using metrics such as accuracy and F1-score. While these metrics are useful, it becomes difficult to identify using them where the model is failing, and how to resolve it. To enable more targeted diagnostic insights of such multilingual hate speech models, we introduce a set of functionalities for the purpose of evaluation. We have been inspired to design this kind of functionalities based on real-world conversation on social media. Considering Hindi as a base language, we craft test cases for each functionality. We name our evaluation dataset HateCheckHIn. To illustrate the utility of these functionalities , we test state-of-the-art transformer based m-BERT model and the Perspective API.

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Which One Is More Toxic? Findings from Jigsaw Rate Severity of Toxic Comments
Millon Das | Punyajoy Saha | Mithun Das
Proceedings of the Third Workshop on Threat, Aggression and Cyberbullying (TRAC 2022)

The proliferation of online hate speech has necessitated the creation of algorithms which can detect toxicity. Most of the past research focuses on this detection as a classification task, but assigning an absolute toxicity label is often tricky. Hence, few of the past works transform the same task into a regression. This paper shows the comparative evaluation of different transformers and traditional machine learning models on a recently released toxicity severity measurement dataset by Jigsaw. We further demonstrate the issues with the model predictions using explainability analysis.

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Hate Speech and Offensive Language Detection in Bengali
Mithun Das | Somnath Banerjee | Punyajoy Saha | Animesh Mukherjee
Proceedings of the 2nd Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics and the 12th International Joint Conference on Natural Language Processing (Volume 1: Long Papers)

Social media often serves as a breeding ground for various hateful and offensive content. Identifying such content on social media is crucial due to its impact on the race, gender, or religion in an unprejudiced society. However, while there is extensive research in hate speech detection in English, there is a gap in hateful content detection in low-resource languages like Bengali. Besides, a current trend on social media is the use of Romanized Bengali for regular interactions. To overcome the existing research’s limitations, in this study, we develop an annotated dataset of 10K Bengali posts consisting of 5K actual and 5K Romanized Bengali tweets. We implement several baseline models for the classification of such hateful posts. We further explore the interlingual transfer mechanism to boost classification performance. Finally, we perform an in-depth error analysis by looking into the misclassified posts by the models. While training actual and Romanized datasets separately, we observe that XLM-Roberta performs the best. Further, we witness that on joint training and few-shot training, MuRIL outperforms other models by interpreting the semantic expressions better. We make our code and dataset public for others.