12 Research Papers Accepted to EMNLP 2022


Papers from CS researchers were accepted to the Empirical Methods in Natural Language Processing (EMNLP) 2022. EMNLP is a leading conference in artificial intelligence and natural language processing. Aside from presenting their research papers, several researchers also organized workshops to gather conference attendees for discussions about current issues confronting NLP and computer science.   


Massively Multilingual Natural Language Understanding
Jack FitzGerald Amazon Alexa, Kay Rottmann Amazon Alexa, Julia Hirschberg Columbia University, Mohit Bansal University of North Carolina, Anna Rumshisky University of Massachusetts Lowell, and Charith Peris Amazon Alexa

3rd Workshop on Figurative Language Processing
Debanjan Ghosh Educational Testing Service, Beata Beigman Klebanov Educational Testing Service, Smaranda Muresan Columbia University, Anna Feldman Montclair State University, Soujanya Poria Singapore University of Technology and Design, and Tuhin Chakrabarty Columbia University

Sharing Stories and Lessons Learned
Diyi Yang Stanford University, Pradeep Dasigi Allen Institute for AI, Sherry Tongshuang Wu Carnegie Mellon University, Tuhin Chakrabarty Columbia University, Yuval Pinter Ben-Gurion University of the Negev, and Mike Zheng Shou National University of Singapore

Accepted Papers

Help me write a Poem – Instruction Tuning as a Vehicle for Collaborative Poetry Writing
Tuhin Chakrabarty Columbia University, Vishakh Padmakumar New York University, He He New York University

Recent work in training large language models (LLMs) to follow natural language instructions has opened up exciting opportunities for natural language interface design. Building on the prior success of large language models in the realm of computer assisted creativity, in this work, we present CoPoet, a collaborative poetry writing system, with the goal of to study if LLM’s actually improve the quality of the generated content. In contrast to auto-completing a user’s text, CoPoet is controlled by user instructions that specify the attributes of the desired text, such as Write a sentence about ‘love’ or Write a sentence ending in ‘fly’. The core component of our system is a language model fine-tuned on a diverse collection of instructions for poetry writing. Our model is not only competitive to publicly available LLMs trained on instructions (InstructGPT), but also capable of satisfying unseen compositional instructions. A study with 15 qualified crowdworkers shows that users successfully write poems with CoPoet on diverse topics ranging from Monarchy to Climate change, which are preferred by third-party evaluators over poems written without the system.

FLUTE: Figurative Language Understanding through Textual Explanations
Tuhin Chakrabarty Columbia University, Arkadiy Saakyan Columbia University, Debanjan Ghosh Educational Testing Service, and Smaranda Muresan Columbia University

Figurative language understanding has been recently framed as a recognizing textual entailment (RTE) task (a.k.a. natural language inference (NLI)). However, similar to classical RTE/NLI datasets they suffer from spurious correlations and annotation artifacts. To tackle this problem, work on NLI has built explanation-based datasets such as eSNLI, allowing us to probe whether language models are right for the right reasons. Yet no such data exists for figurative language, making it harder to assess genuine understanding of such expressions. To address this issue, we release FLUTE, a dataset of 9,000 figurative NLI instances with explanations, spanning four categories: Sarcasm, Simile, Metaphor, and Idioms. We collect the data through a Human-AI collaboration framework based on GPT-3, crowd workers, and expert annotators. We show how utilizing GPT-3 in conjunction with human annotators (novices and experts) can aid in scaling up the creation of datasets even for such complex linguistic phenomena as figurative language. The baseline performance of the T5 model fine-tuned on FLUTE shows that our dataset can bring us a step closer to developing models that understand figurative language through textual explanations.

Fine-tuned Language Models are Continual Learners
Thomas Scialom Columbia University, Tuhin Chakrabarty Columbia University, and Smaranda Muresan Columbia University

Recent work on large language models relies on the intuition that most natural language processing tasks can be described via natural language instructions and that models trained on these instructions show strong zero-shot performance on several standard datasets. However, these models even though impressive still perform poorly on a wide range of tasks outside of their respective training and evaluation sets.To address this limitation, we argue that a model should be able to keep extending its knowledge and abilities, without forgetting previous skills. In spite of the limited success of Continual Learning, we show that Fine-tuned Language Models can be continual learners.We empirically investigate the reason for this success and conclude that Continual Learning emerges from self-supervision pre-training. Our resulting model Continual-T0 (CT0) is able to learn 8 new diverse language generation tasks, while still maintaining good performance on previous tasks, spanning in total of 70 datasets. Finally, we show that CT0 is able to combine instructions in ways it was never trained for, demonstrating some level of instruction compositionality.

Multitask Instruction-based Prompting for Fallacy Recognition
Tariq Alhindi Columbia University, Tuhin Chakrabarty Columbia University, Elena Musi University of Liverpool, and Smaranda Muresan Columbia University

Fallacies are used as seemingly valid arguments to support a position and persuade the audience about its validity. Recognizing fallacies is an intrinsically difficult task both for humans and machines. Moreover, a big challenge for computational models lies in the fact that fallacies are formulated differently across the datasets with differences in the input format (e.g., question-answer pair, sentence with fallacy fragment), genre (e.g., social media, dialogue, news), as well as types and number of fallacies (from 5 to 18 types per dataset). To move towards solving the fallacy recognition task, we approach these differences across datasets as multiple tasks and show how instruction-based prompting in a multitask setup based on the T5 model improves the results against approaches built for a specific dataset such as T5, BERT or GPT-3. We show the ability of this multitask prompting approach to recognize 28 unique fallacies across domains and genres and study the effect of model size and prompt choice by analyzing the per-class (i.e., fallacy type) results. Finally, we analyze the effect of annotation quality on model performance, and the feasibility of complementing this approach with external knowledge.

CONSISTENT: Open-Ended Question Generation From News Articles
Tuhin Chakrabarty Columbia University, Justin Lewis The New York Times R&D, and Smaranda Muresan Columbia University

Recent work on question generation has largely focused on factoid questions such as who, what, where, when about basic facts. Generating open-ended why, how, what, etc. questions that require long-form answers have proven more difficult. To facilitate the generation of open-ended questions, we propose CONSISTENT, a new end-to-end system for generating open-ended questions that are answerable from and faithful to the input text. Using news articles as a trustworthy foundation for experimentation, we demonstrate our model’s strength over several baselines using both automatic and human=based evaluations. We contribute an evaluation dataset of expert-generated open-ended questions.We discuss potential downstream applications for news media organizations.

SafeText: A Benchmark for Exploring Physical Safety in Language Models
Sharon Levy University of California, Santa Barbara, Emily Allaway Columbia University, Melanie Subbiah Columbia University, Lydia Chilton Columbia University, Desmond Patton Columbia University, Kathleen McKeown Columbia University, and William Yang Wang University of California, Santa Barbara

Understanding what constitutes safe text is an important issue in natural language processing and can often prevent the deployment of models deemed harmful and unsafe. One such type of safety that has been scarcely studied is commonsense physical safety, i.e. text that is not explicitly violent and requires additional commonsense knowledge to comprehend that it leads to physical harm. We create the first benchmark dataset, SafeText, comprising real-life scenarios with paired safe and physically unsafe pieces of advice. We utilize SafeText to empirically study commonsense physical safety across various models designed for text generation and commonsense reasoning tasks. We find that state-of-the-art large language models are susceptible to the generation of unsafe text and have difficulty rejecting unsafe advice. As a result, we argue for further studies of safety and the assessment of commonsense physical safety in models before release.

Learning to Revise References for Faithful Summarization
Griffin Adams Columbia University, Han-Chin Shing Amazon AWS AI, Qing Sun Amazon AWS AI, Christopher Winestock Amazon AWS AI, Kathleen McKeown Columbia University, and Noémie Elhadad Columbia University

In real-world scenarios with naturally occurring datasets, reference summaries are noisy and may contain information that cannot be inferred from the source text. On large news corpora, removing low quality samples has been shown to reduce model hallucinations. Yet, for smaller, and/or noisier corpora, filtering is detrimental to performance. To improve reference quality while retaining all data, we propose a new approach: to selectively re-write unsupported reference sentences to better reflect source data. We automatically generate a synthetic dataset of positive and negative revisions by corrupting supported sentences and learn to revise reference sentences with contrastive learning. The intensity of revisions is treated as a controllable attribute so that, at inference, diverse candidates can be over-generated-then-rescored to balance faithfulness and abstraction. To test our methods, we extract noisy references from publicly available MIMIC-III discharge summaries for the task of hospital-course summarization, and vary the data on which models are trained. According to metrics and human evaluation, models trained on revised clinical references are much more faithful, informative, and fluent than models trained on original or filtered data.

Mitigating Covertly Unsafe Text within Natural Language Systems
Alex Mei University of California, Santa Barbara, Anisha Kabir University of California, Santa Barbara, Sharon Levy University of California, Santa Barbara, Melanie Subbiah Columbia University, Emily Allaway Columbia University, John N. Judge University of California, Santa Barbara, Desmond Patton University of Pennsylvania, Bruce Bimber University of California, Santa Barbara, Kathleen McKeown Columbia University, and William Yang Wang University of California, Santa Barbara

An increasingly prevalent problem for intelligent technologies is text safety, as uncontrolled systems may generate recommendations to their users that lead to injury or life-threatening consequences. However, the degree of explicitness of a generated statement that can cause physical harm varies. In this paper, we distinguish types of text that can lead to physical harm and establish one particularly underexplored category: covertly unsafe text. Then, we further break down this category with respect to the system’s information and discuss solutions to mitigate the generation of text in each of these subcategories. Ultimately, our work defines the problem of covertly unsafe language that causes physical harm and argues that this subtle yet dangerous issue needs to be prioritized by stakeholders and regulators. We highlight mitigation strategies to inspire future researchers to tackle this challenging problem and help improve safety within smart systems.

Affective Idiosyncratic Responses to Music
Sky CH-Wang Columbia University, Evan Li Columbia University, Oliver Li Columbia University, Smaranda Muresan Columbia University, and Zhou Yu Columbia University

Affective responses to music are highly personal. Despite consensus that idiosyncratic factors play a key role in regulating how listeners emotionally respond to music, precisely measuring the marginal effects of these variables has proved challenging. To address this gap, we develop computational methods to measure affective responses to music from over 403M listener comments on a Chinese social music platform. Building on studies from music psychology in systematic and quasi-causal analyses, we test for musical, lyrical, contextual, demographic, and mental health effects that drive listener affective responses. Finally, motivated by the social phenomenon known as 网抑云 (wǎng-yì-yún), we identify influencing factors of platform user self-disclosures, the social support they receive, and notable differences in discloser user activity.

Robots-Dont-Cry: Understanding Falsely Anthropomorphic Utterances in Dialog Systems
David Gros University of California, Davis, Yu Li Columbia University, and Zhou Yu Columbia University

Dialog systems are often designed or trained to output human-like responses. However, some responses may be impossible for a machine to truthfully say (e.g. “that movie made me cry”). Highly anthropomorphic responses might make users uncomfortable or implicitly deceive them into thinking they are interacting with a human. We collect human ratings on the feasibility of approximately 900 two-turn dialogs sampled from 9 diverse data sources. Ratings are for two hypothetical machine embodiments: a futuristic humanoid robot and a digital assistant. We find that for some data-sources commonly used to train dialog systems, 20-30% of utterances are not viewed as possible for a machine. Rating is marginally affected by machine embodiment. We explore qualitative and quantitative reasons for these ratings. Finally, we build classifiers and explore how modeling configuration might affect output permissibly, and discuss implications for building less falsely anthropomorphic dialog systems.

Just Fine-tune Twice: Selective Differential Privacy for Large Language Models
Weiyan Shi Columbia University, Ryan Patrick Shea Columbia University, Si Chen Columbia University, Chiyuan Zhang Google Research, Ruoxi Jia Virginia Tech, and Zhou Yu Columbia University

Protecting large language models from privacy leakage is becoming increasingly crucial with their wide adoption in real-world products. Yet applying *differential privacy* (DP), a canonical notion with provable privacy guarantees for machine learning models, to those models remains challenging due to the trade-off between model utility and privacy loss. Utilizing the fact that sensitive information in language data tends to be sparse, Shi et al. (2021) formalized a DP notion extension called *Selective Differential Privacy* (SDP) to protect only the sensitive tokens defined by a policy function. However, their algorithm only works for RNN-based models. In this paper, we develop a novel framework, *Just Fine-tune Twice* (JFT), that achieves SDP for state-of-the-art large transformer-based models. Our method is easy to implement: it first fine-tunes the model with *redacted* in-domain data, and then fine-tunes it again with the *original* in-domain data using a private training mechanism. Furthermore, we study the scenario of imperfect implementation of policy functions that misses sensitive tokens and develop systematic methods to handle it. Experiments show that our method achieves strong utility compared to previous baselines. We also analyze the SDP privacy guarantee empirically with the canary insertion attack.

Focus! Relevant and Sufficient Context Selection for News Image Captioning
Mingyang Zhou University of California, Davis, Grace Luo University of California, Berkeley, Anna Rohrbach University of California, Berkeley, and Zhou Yu Columbia University

News Image Captioning requires describing an image by leveraging additional context from a news article. Previous works only coarsely leverage the article to extract the necessary context, which makes it challenging for models to identify relevant events and named entities. In our paper, we first demonstrate that by combining more fine-grained context that captures the key named entities (obtained via an oracle) and the global context that summarizes the news, we can dramatically improve the model’s ability to generate accurate news captions. This begs the question, how to automatically extract such key entities from an image? We propose to use the pre-trained vision and language retrieval model CLIP to localize the visually grounded entities in the news article and then capture the non-visual entities via an open relation extraction model. Our experiments demonstrate that by simply selecting a better context from the article, we can significantly improve the performance of existing models and achieve new state-of-the-art performance on multiple benchmarks.