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Mohit Iyyer

49 accepted papers

2026

Bio-Inspired Self-Supervised Learning for Wrist-worn IMU Signals

ICML 2026poster

Wearable accelerometers have enabled large-scale health and wellness monitoring, yet learning robust human-activity representations has been constrained by the scarcity of labeled data. While self-supervised learning offers a potential remedy, existing approaches treat sensor streams as unstructured…

Cited by 0SourceScholar
2026

How2Everything: Mining the Web for How-to Procedures to Evaluate and Improve LLMs

ICML 2026poster

Generating step-by-step "how-to" procedures is a key LLM capability: how-to advice is commonly requested in chatbots, and step-by-step planning is critical for reasoning over complex tasks. Yet, measuring and improving procedural validity at scale on real-world tasks remains challenging and understu…

Cited by 0SourceScholar
2025

BLEUBERI: BLEU is a surprisingly effective reward for instruction following

NeurIPS 2025poster

Reward models are central to aligning LLMs with human preferences, but they are costly to train, requiring large-scale human-labeled preference data and powerful pretrained LLM backbones. Meanwhile, the increasing availability of high-quality synthetic instruction-following datasets raises the quest…

Cited by 0SourcecodeScholar
2025

CaLMQA: Exploring culturally specific long-form question answering across 23 languages

ACL 2025long

Despite rising global usage of large language models (LLMs), their ability to generate *long-form* answers to *culturally specific* questions remains unexplored in many languages. To fill this gap, we perform the first study of textual multilingual long-form QA by creating CaLMQA, a dataset of **51.…

2025

Does quantization affect models’ performance on long-context tasks?

EMNLP 2025

Large language models (LLMs) now support context windows exceeding 128K tokens, but this comes with significant memory requirements and high inference latency. Quantization can mitigate these costs, but may degrade performance. In this work, we present the first systematic evaluation of quantized LL

2025

Localizing and Mitigating Errors in Long-form Question Answering

ACL 2025finding

Long-form question answering (LFQA) aims to provide thorough and in-depth answers to complex questions, enhancing comprehension. However, such detailed responses are prone to hallucinations and factual inconsistencies, challenging their faithful evaluation. This work introduces HaluQuestQA, the firs…

2025

OWL: Probing Cross-Lingual Recall of Memorized Texts via World Literature

EMNLP 2025

Large language models (LLMs) are known to memorize and recall English text from their pretraining data. However, the extent to which this ability generalizes to non-English languages or transfers across languages remains unclear. This paper investigates multilingual and cross-lingual memorization in

2025

People who frequently use ChatGPT for writing tasks are accurate and robust detectors of AI-generated text

ACL 2025long

In this paper, we study how well humans can detect text generated by commercial LLMs (GPT-4o, Claude, o1). We hire annotators to read 300 non-fiction English articles, label them as either human-written or AI-generated, and provide paragraph-length explanations for their decisions. Our experiments s…

2025

VeriFastScore: Speeding up long-form factuality evaluation

EMNLP 2025

Metrics like FactScore and VeriScore that evaluate long-form factuality operate by decomposing an input response into atomic claims and then individually verifying each claim. While effective and interpretable, these methods incur numerous LLM calls and can take upwards of 100s to evaluate a single

2024

BooookScore: A systematic exploration of book-length summarization in the era of LLMs

ICLR 2024oral

Summarizing book-length documents ($>$100K tokens) that exceed the context window size of large language models (LLMs) requires first breaking the input document into smaller chunks and then prompting an LLM to merge, update, and compress chunk-level summaries. Despite the complexity and importance…

2024

FreshLLMs: Refreshing Large Language Models with Search Engine Augmentation

ACL 2024findings

Since most large language models (LLMs) are trained once and never updated, they struggle to dynamically adapt to our ever-changing world. In this work, we present FreshQA, a dynamic QA benchmark that tests a model’s ability to answer questions that may require reasoning over up-to-date world knowle…

2024

GEE! Grammar Error Explanation with Large Language Models

NAACL 2024findings

Existing grammatical error correction tools do not provide natural language explanations of the errors that they correct in user-written text. However, such explanations are essential for helping users learn the language by gaining a deeper understanding of its grammatical rules (DeKeyser, 2003; Ell…

2024

Multistage Collaborative Knowledge Distillation from a Large Language Model for Semi-Supervised Sequence Generation

ACL 2024long

We study semi-supervised sequence generation tasks, where the few labeled examples are too scarce to finetune a model, and meanwhile, few-shot prompted large language models (LLMs) exhibit room for improvement. In this paper, we present the discovery that a student model distilled from a few-shot pr…

2024

One Thousand and One Pairs: A “novel” challenge for long-context language models

EMNLP 2024main

Synthetic long-context LLM benchmarks (e.g., “needle-in-the-haystack”) test only surface-level retrieval capabilities; but how well can long-context LLMs retrieve, synthesize, and reason over information across book-length inputs? We address this question by creating NoCha, a dataset of 1,001 minima…

2024

PostMark: A Robust Blackbox Watermark for Large Language Models

EMNLP 2024main

The most effective techniques to detect LLM-generated text rely on inserting a detectable signature—or watermark—during the model’s decoding process. Most existing watermarking methods require access to the underlying LLM’s logits, which LLM API providers are loath to share due to fears of model dis…

2024

Suri: Multi-constraint Instruction Following in Long-form Text Generation

EMNLP 2024finding

Existing research on instruction following largely focuses on tasks with simple instructions and short responses. In this work, we explore multi-constraint instruction following for generating long-form text. We create Suri, a dataset with 20K human-written long-form texts paired with LLM-generated…

2024

TopicGPT: A Prompt-based Topic Modeling Framework

NAACL 2024long

Topic modeling is a well-established technique for exploring text corpora. Conventional topic models (e.g., LDA) represent topics as bags of words that often require “reading the tea leaves” to interpret; additionally, they offer users minimal control over the formatting and specificity of resulting…

2024

VeriScore: Evaluating the factuality of verifiable claims in long-form text generation

EMNLP 2024finding

Existing metrics for evaluating the factuality of long-form text, such as FACTSCORE (Min et al., 2023) and SAFE (Wei et al., 2024), decompose an input text into “atomic claims” and verify each against a knowledge base like Wikipedia. These metrics are not suitable for most generation tasks because t…

2023

$k$NN-LM Does Not Improve Open-ended Text Generation

EMNLP 2023long main

In this paper, we study the generation quality of interpolation-based retrieval-augmented language models (LMs). These methods, best exemplified by the $k$NN-LM, interpolate the LM's predicted distribution of the next word with a distribution formed from the most relevant retrievals for a given pref…

Cited by 0SourceScholar
2023

A Critical Evaluation of Evaluations for Long-form Question Answering

ACL 2023long

Long-form question answering (LFQA) enables answering a wide range of questions, but its flexibility poses enormous challenges for evaluation. We perform the first targeted study of the evaluation of long-form answers, covering both human and automatic evaluation practices. We hire domain experts in…

2023

A Framework for Exploring Player Perceptions of LLM-Generated Dialogue in Commercial Video Games

EMNLP 2023long findings

The growing capabilities of large language models (LLMs) have inspired recent efforts to integrate LLM-generated dialogue into video games. However, evaluation remains a major challenge: how do we assess the player experience in a commercial game augmented with LLM-generated dialogue? To explore thi…

Cited by 0SourceScholar
2023

FActScore: Fine-grained Atomic Evaluation of Factual Precision in Long Form Text Generation

EMNLP 2023long main

Evaluating the factuality of long-form text generated by large language models (LMs) is non-trivial because (1) generations often contain a mixture of supported and unsupported pieces of information, making binary judgments of quality inadequate, and (2) human evaluation is time-consuming and costly…

Cited by 0SourcecodeScholar
2023

PaRaDe: Passage Ranking using Demonstrations with LLMs

EMNLP 2023short findings

Recent studies show that large language models (LLMs) can be instructed to effectively perform zero-shot passage re-ranking, in which the results of a first stage retrieval method, such as BM25, are rated and reordered to improve relevance. In this work, we improve LLM-based re-ranking by algorithmi…

Cited by 0SourceScholar
2023

Paraphrasing evades detectors of AI-generated text, but retrieval is an effective defense

NeurIPS 2023poster

The rise in malicious usage of large language models, such as fake content creation and academic plagiarism, has motivated the development of approaches that identify AI-generated text, including those based on watermarking or outlier detection. However, the robustness of these detection algorithms…

2022

DEMETR: Diagnosing Evaluation Metrics for Translation

EMNLP 2022main

While machine translation evaluation metrics based on string overlap (e.g., BLEU) have their limitations, their computations are transparent: the BLEU score assigned to a particular candidate translation can be traced back to the presence or absence of certain words. The operations of newer learned…

2022

Exploring Document-Level Literary Machine Translation with Parallel Paragraphs from World Literature

EMNLP 2022main

Literary translation is a culturally significant task, but it is bottlenecked by the small number of qualified literary translators relative to the many untranslated works published around the world. Machine translation (MT) holds potential to complement the work of human translators by improving bo…

2022

Modeling Exemplification in Long-form Question Answering via Retrieval

NAACL 2022long

Exemplification is a process by which writers explain or clarify a concept by providing an example. While common in all forms of writing, exemplification is particularly useful in the task of long-form question answering (LFQA), where a complicated answer can be made more understandable through simp…

2022

Overcoming Catastrophic Forgetting in Zero-Shot Cross-Lingual Generation

EMNLP 2022main

In this paper, we explore the challenging problem of performing a generative task in a target language when labeled data is only available in English, using summarization as a case study. We assume a strict setting with no access to parallel data or machine translation and find that common transfer…

2022

RankGen: Improving Text Generation with Large Ranking Models

EMNLP 2022main

Given an input sequence (or prefix), modern language models often assign high probabilities to output sequences that are repetitive, incoherent, or irrelevant to the prefix; as such, model-generated text also contains such artifacts. To address these issues we present RankGen, a 1.2B parameter encod…

2022

SLING: Sino Linguistic Evaluation of Large Language Models

EMNLP 2022main

To understand what kinds of linguistic knowledge are encoded by pretrained Chinese language models (LMs), we introduce the benchmark of Sino LINGuistics (SLING), which consists of 38K minimal sentence pairs in Mandarin Chinese grouped into 9 high-level linguistic phenomena. Each pair demonstrates th…

2022

You can’t pick your neighbors, or can you? When and How to Rely on Retrieval in the kNN-LM

EMNLP 2022finding

Retrieval-enhanced language models (LMs), which condition their predictions on text retrieved from large external datastores, have recently shown significant perplexity improvements compared to standard LMs. One such approach, the kNN-LM, interpolates any existing LM’s predictions with the output of…

2021

Do Long-Range Language Models Actually Use Long-Range Context?

EMNLP 2021main

Language models are generally trained on short, truncated input sequences, which limits their ability to use discourse-level information present in long-range context to improve their predictions. Recent efforts to improve the efficiency of self-attention have led to a proliferation of long-range Tr…

Cited by 78SourcePDFScholar
2021

Energy-Based Reranking: Improving Neural Machine Translation Using Energy-Based Models

ACL 2021long

The discrepancy between maximum likelihood estimation (MLE) and task measures such as BLEU score has been studied before for autoregressive neural machine translation (NMT) and resulted in alternative training algorithms (Ranzato et al., 2016; Norouzi et al., 2016; Shen et al., 2016; Wu et al., 2018…

2021

IGA: An Intent-Guided Authoring Assistant

EMNLP 2021main

While large-scale pretrained language models have significantly improved writing assistance functionalities such as autocomplete, more complex and controllable writing assistants have yet to be explored. We leverage advances in language modeling to build an interactive writing assistant that generat…

2021

Improved Latent Tree Induction with Distant Supervision via Span Constraints

EMNLP 2021main

For over thirty years, researchers have developed and analyzed methods for latent tree induction as an approach for unsupervised syntactic parsing. Nonetheless, modern systems still do not perform well enough compared to their supervised counterparts to have any practical use as structural annotatio…

2021

Phrase-BERT: Improved Phrase Embeddings from BERT with an Application to Corpus Exploration

EMNLP 2021main

Phrase representations derived from BERT often do not exhibit complex phrasal compositionality, as the model relies instead on lexical similarity to determine semantic relatedness. In this paper, we propose a contrastive fine-tuning objective that enables BERT to produce more powerful phrase embeddi…

2021

STraTA: Self-Training with Task Augmentation for Better Few-shot Learning

EMNLP 2021main

Despite their recent successes in tackling many NLP tasks, large-scale pre-trained language models do not perform as well in few-shot settings where only a handful of training examples are available. To address this shortcoming, we propose STraTA, which stands for Self-Training with Task Augmentatio…

2021

TABBIE: Pretrained Representations of Tabular Data

NAACL 2021long

Existing work on tabular representation-learning jointly models tables and associated text using self-supervised objective functions derived from pretrained language models such as BERT. While this joint pretraining improves tasks involving paired tables and text (e.g., answering questions about tab…

2021

The Perils of Using Mechanical Turk to Evaluate Open-Ended Text Generation

EMNLP 2021main

Recent text generation research has increasingly focused on open-ended domains such as story and poetry generation. Because models built for such tasks are difficult to evaluate automatically, most researchers in the space justify their modeling choices by collecting crowdsourced human judgments of…

Cited by 136SourcePDFScholar
2020

Thieves on Sesame Street! Model Extraction of BERT-based APIs

ICLR 2020poster

We study the problem of model extraction in natural language processing, in which an adversary with only query access to a victim model attempts to reconstruct a local copy of that model. Assuming that both the adversary and victim model fine-tune a large pretrained language model such as BERT (Devl…

Cited by 235SourcecodeScholar
2018

Deep contextualized word representations

ICLR 2018poster

We introduce a new type of deep contextualized word representation that models both (1) complex characteristics of word use (e.g., syntax and semantics), and (2) how these uses vary across linguistic contexts (i.e., to model polysemy). Our word vectors are learned functions of the internal states o…

Cited by 0SourceScholar
2017

The Amazing Mysteries of the Gutter: Drawing Inferences Between Panels in Comic Book Narratives

CVPR 2017spotlight

Visual narrative is often a combination of explicit information and judicious omissions, relying on the viewer to supply missing details. In comics, most movements in time and space are hidden in the "gutters" between panels. To follow the story, readers logically connect panels together by inferrin…

Cited by 132PDFScholar
2016

Ask Me Anything: Dynamic Memory Networks for Natural Language Processing

ICML 2016poster

Most tasks in natural language processing can be cast into question answering (QA) problems over language input. We introduce the dynamic memory network (DMN), a neural network architecture which processes input sequences and questions, forms episodic memories, and generates relevant answers. Questi…

Cited by 1616SourcePDFScholar