Zefan Cai
Author directory2026
Test-Time Training with Next-Token Prediction
Xuan Ouyang | Zefan Cai | Junjie Hu
Findings of the Association for Computational Linguistics: EMNLP 2026
Xuan Ouyang | Zefan Cai | Junjie Hu
Findings of the Association for Computational Linguistics: EMNLP 2026
Next-token prediction is the self-supervised signal that trains language models, and every observed prompt token provides the same signal at test time. We study whether this signal can define the inner-loop objective for test-time training (TTT) in pretrained long-context language models. Existing in-place TTT methods store prompt information in fast weights, but they train each write to match a learned shortcut target: an internal pattern that may be easy to predict, yet is not the trajectory the model uses to form its next-token distribution. We introduce Test-Time Training with Next-Token Prediction (TTT-NTP), a drop-in fast-weight adaptation method for pretrained LLMs that instead supervises updates using the model’s own next contextual hidden state. This makes each local write follow the same causal computation that supports next-token prediction, without aggregating over a neighborhood of positions: the value target is a pointwise linear projection of a single next-position contextual state. Across four backbones from three model families, Llama-3.1-8B, Mistral-7B-v0.3, Qwen3-4B, and Qwen3-0.6B, TTT-NTP is the only method that consistently improves RULER Full-13 over the released backbone, by 2.9 to 4.1 points, while aggregate commonsense and knowledge performance is preserved. Our code is publicly available at https://github.com/yancyou/TTT-NTP.
MENTOR: Efficient Autoregressive Image Generation with Balanced Multimodal Control
Haozhe Zhao | Zefan Cai | Shuzheng Si | Liang Chen | Jiuxiang Gu | Wen Xiao | Minjia Zhang | Junjie Hu
Findings of the Association for Computational Linguistics: ACL 2026
Haozhe Zhao | Zefan Cai | Shuzheng Si | Liang Chen | Jiuxiang Gu | Wen Xiao | Minjia Zhang | Junjie Hu
Findings of the Association for Computational Linguistics: ACL 2026
Recent text-to-image models achieve impressive visual quality but still face challenges in precise controllability, balancing multimodal inputs, and high training cost for multimodal image generation. To address these limitations, we propose MENTOR, an autoregressive (AR) framework with a two-stage training paradigm for controllable multimodal image generation: (1) a multimodal alignment stage that establishes robust pixel and semantic-level alignment between inputs and generated tokens, followed by (2) a multimodal instruction tuning stage that balance model’s integration of multimodal inputs and enhance generation controllability. Extensive experiments on DreamBench++ and DreamBench demonstrate that, despite modest model size and training resources, achieves a strong balance between textual and visual guidance for controllable image generation, delivering competitive performance at significantly lower computational cost compared to leading baselines. Moreover, our approach attains superior image reconstruction fidelity, broad adaptability across different tasks, and training efficiency.
MMGR: Multi-Modal Generative Reasoning Benchmark and Evaluation
Zefan Cai | Haoyi Qiu | Tianyi Ma | Haozhe Zhao | Gengze Zhou | Tingting Liao | Xinyan Velocity Yu | Kung-Hsiang Huang | Ke Wan | Shawn Lin | Parisa Kordjamshidi | Minjia Zhang | Wen Xiao | Jiuxiang Gu | Nanyun Peng | Junjie Hu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Zefan Cai | Haoyi Qiu | Tianyi Ma | Haozhe Zhao | Gengze Zhou | Tingting Liao | Xinyan Velocity Yu | Kung-Hsiang Huang | Ke Wan | Shawn Lin | Parisa Kordjamshidi | Minjia Zhang | Wen Xiao | Jiuxiang Gu | Nanyun Peng | Junjie Hu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Modern multimodal generative models can synthesize visually compelling images and videos, but it remains unclear whether this visual fluency reflects genuine reasoning: when prompted to generate a solution, can a model preserve the physical, logical, spatial, and temporal constraints a task requires, or does it merely produce plausible-looking media? To answer this question, we introduce MMGR (Multi-Modal Generative Reasoning Benchmark and Evaluation), a benchmark for evaluating generative reasoning across video, image, and language-based systems. MMGR covers 10 tasks from three domains (Abstract Reasoning, Embodied Navigation, and Physical Commonsense) and probes five reasoning abilities: Physical, Logical, 2D Spatial, 3D Spatial, and Temporal. Its evaluation emphasizes answer-verifiable tasks and, for video generation, process-aware chain-of-frame reasoning, where intermediate frames must form valid steps toward the target outcome rather than visually smooth but incorrect transitions. Evaluating state-of-the-art video generators, image generators, and LLM/VLM baselines reveals a sharp gap between visual quality and reasoning correctness: video models perform best on Physical Commonsense, but remain weak on symbolic tasks such as Sudoku, ARC, and Math, and brittle in cross-view embodied navigation. Image generators often outperform video generators on embodied navigation despite lacking temporal outputs, showing that longer visual generation does not automatically yield stronger reasoning. MMGR reframes evaluation of multimodal generation from whether outputs look realistic to whether they solve the underlying reasoning problem.
2025
LLM Critics Help Catch Bugs in Mathematics: Towards a Better Mathematical Verifier with Natural Language Feedback
Bofei Gao | Zefan Cai | Runxin Xu | Peiyi Wang | Ce Zheng | Runji Lin | Keming Lu | Dayiheng Liu | Chang Zhou | Wen Xiao | Tianyu Liu | Baobao Chang
Findings of the Association for Computational Linguistics: ACL 2025
Bofei Gao | Zefan Cai | Runxin Xu | Peiyi Wang | Ce Zheng | Runji Lin | Keming Lu | Dayiheng Liu | Chang Zhou | Wen Xiao | Tianyu Liu | Baobao Chang
Findings of the Association for Computational Linguistics: ACL 2025
In recent progress, mathematical verifiers have achieved success in mathematical reasoning tasks by validating the correctness of solutions generated by policy models. However, existing verifiers are trained with binary classification labels, which are not informative enough for the model to accurately assess the solutions. To mitigate the aforementioned insufficiency of binary labels, we introduce step-wise natural language feedback as rationale labels, that is, the correctness of each step and the detailed explanations. In this paper, we propose Math-Minos, a natural language feedback-enhanced verifier by constructing automatically generated training data and a two-stage training paradigm for effective training and efficient inference. Our experiments reveal that a small set of natural language feedback can significantly boost the performance of the verifier in both verification and reinforcement learning and also significantly alleviates the data-demanding problems of the reward model with an over 700% data efficiency improvement.
2024
DialogVCS: Robust Natural Language Understanding in Dialogue System Upgrade
Zefan Cai | Xin Zheng | Tianyu Liu | Haoran Meng | Jiaqi Han | Gang Yuan | Binghuai Lin | Baobao Chang | Yunbo Cao
Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Zefan Cai | Xin Zheng | Tianyu Liu | Haoran Meng | Jiaqi Han | Gang Yuan | Binghuai Lin | Baobao Chang | Yunbo Cao
Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
In the constant updates of the product dialogue systems, we need to retrain the natural language understanding (NLU) model as new data from the real users would be merged into the existing data accumulated in the last updates. Within the newly added data, new intents would emerge and might have semantic entanglement with the existing intents, e.g. new intents that are semantically too specific or generic are actually a subset or superset of some existing intents in the semantic space, thus impairing the robustness of the NLU model.As the first attempt to solve this problem, we setup a new benchmark consisting of 4 Dialogue Version Control dataSets (DialogVCS). We formulate the intent detection with imperfect data in the system update as a multi-label classification task with positive but unlabeled intents, which asks the models to recognize all the proper intents, including the ones with semantic entanglement, in the inference.We also propose comprehensive baseline models and conduct in-depth analyses for the benchmark, showing that the semantically entangled intents can be effectively recognized with an automatic workflow. Our code and dataset are available at https://github.com/Zefan-Cai/DialogVCS.
Mitigating Language-Level Performance Disparity in mPLMs via Teacher Language Selection and Cross-lingual Self-Distillation
Haozhe Zhao | Zefan Cai | Shuzheng Si | Liang Chen | Yufeng He | Kaikai An | Baobao Chang
Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Haozhe Zhao | Zefan Cai | Shuzheng Si | Liang Chen | Yufeng He | Kaikai An | Baobao Chang
Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Large-scale multilingual Pretrained Language Models (mPLMs) yield impressive performance on cross-language tasks, yet significant performance disparities exist across different languages within the same mPLM. Previous studies endeavored to narrow these disparities by supervise fine-tuning the mPLMs with multilingual data.However, obtaining labeled multilingual data is time-consuming, and fine-tuning mPLM with limited labeled multilingual data merely encapsulates the knowledge specific to the labeled data.Therefore, we introduce ALSACE to leverage the learned knowledge from the well-performing languages to guide under-performing ones within the same mPLM, eliminating the need for additional labeled multilingual data. Experiments show that ALSACE effectively mitigates language-level performance disparity across various mPLMs while showing the competitive performance on different multilingual NLU tasks, ranging from full resource to limited resource settings. The code for our approach is available at https://github.com/pkunlp-icler/ALSACE.
PCA-Bench: Evaluating Multimodal Large Language Models in Perception-Cognition-Action Chain
Liang Chen | Yichi Zhang | Shuhuai Ren | Haozhe Zhao | Zefan Cai | Yuchi Wang | Peiyi Wang | Xiangdi Meng | Tianyu Liu | Baobao Chang
Findings of the Association for Computational Linguistics: ACL 2024
Liang Chen | Yichi Zhang | Shuhuai Ren | Haozhe Zhao | Zefan Cai | Yuchi Wang | Peiyi Wang | Xiangdi Meng | Tianyu Liu | Baobao Chang
Findings of the Association for Computational Linguistics: ACL 2024
We present PCA-Bench, a multimodal decision-making benchmark for evaluating the integrated capabilities of Multimodal Large Language Models (MLLMs). Departing from previous benchmarks focusing on simplistic tasks and individual model capability, PCA-Bench introduces three complex scenarios: autonomous driving, domestic robotics, and open-world games. Given task instructions and diverse contexts, the model is required to seamlessly integrate multiple capabilities of Perception, Cognition, and Action in a reasoning chain to make accurate decisions. Moreover, PCA-Bench features error localization capabilities, scrutinizing model inaccuracies in areas such as perception, knowledge, or reasoning. This enhances the reliability of deploying MLLMs. To balance accuracy and efficiency in evaluation, we propose PCA-Eval, an automatic evaluation protocol, and assess 10 prevalent MLLMs. The results reveal significant performance disparities between open-source models and powerful proprietary models like GPT-4 Vision. To address this, we introduce Embodied-Instruction-Evolution (EIE), an automatic framework for synthesizing instruction tuning examples in multimodal embodied environments. EIE generates 7,510 training examples in PCA-Bench and enhances the performance of open-source MLLMs, occasionally surpassing GPT-4 Vision (+3% in decision accuracy), thereby validating the effectiveness of EIE. Our findings suggest that robust MLLMs like GPT4-Vision show promise for decision-making in embodied agents, opening new avenues for MLLM research. All benchmark data and evaluation code are made public.
Improving the Robustness of Distantly-Supervised Named Entity Recognition via Uncertainty-Aware Teacher Learning and Student-Student Collaborative Learning
Shuzheng Si | Helan Hu | Haozhe Zhao | Shuang Zeng | Kaikai An | Zefan Cai | Baobao Chang
Findings of the Association for Computational Linguistics: ACL 2024
Shuzheng Si | Helan Hu | Haozhe Zhao | Shuang Zeng | Kaikai An | Zefan Cai | Baobao Chang
Findings of the Association for Computational Linguistics: ACL 2024
Distantly-Supervised Named Entity Recognition (DS-NER) effectively alleviates the burden of annotation, but meanwhile suffers from the label noise. Recent works attempt to adopt the teacher-student framework to gradually refine the training labels and improve the overall robustness. However, we argue that these teacher-student methods achieve limited performance because the poor calibration of the teacher network produces incorrectly pseudo-labeled samples, leading to error propagation. Therefore, we attempt to mitigate this issue by proposing: (1) Uncertainty-Aware Teacher Learning that leverages the prediction uncertainty to reduce the number of incorrect pseudo labels in the self-training stage; (2) Student-Student Collaborative Learning that allows the transfer of reliable labels between two student networks instead of indiscriminately relying on all pseudo labels from its teacher. This approach further enables a full exploration of mislabeled samples rather than simply filtering unreliable pseudo-labeled samples. We evaluate our proposed method on five DS-NER datasets, demonstrating that our method is superior to the state-of-the-art DS-NER denoising methods.
Large Language Models are not Fair Evaluators
Peiyi Wang | Lei Li | Liang Chen | Zefan Cai | Dawei Zhu | Binghuai Lin | Yunbo Cao | Lingpeng Kong | Qi Liu | Tianyu Liu | Zhifang Sui
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Peiyi Wang | Lei Li | Liang Chen | Zefan Cai | Dawei Zhu | Binghuai Lin | Yunbo Cao | Lingpeng Kong | Qi Liu | Tianyu Liu | Zhifang Sui
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
In this paper, we uncover a positional bias in the evaluation paradigm of adopting large language models (LLMs), e.g., GPT-4, as a referee to score and compare the quality of responses generated by candidate models. We find that the quality ranking of candidate responses can be easily hacked by simply altering their order of appearance in the context. This manipulation allows us to skew the evaluation result, making one model appear considerably superior to the other, e.g., Vicuna-13B could beat ChatGPT on 66 over 80 tested queries with ChatGPT as an evaluator. We propose a simple yet effective calibration framework to address our discovered positional bias.To evaluate the effectiveness of our framework, we manually annotate the “win/tie/lose” outcomes of responses from ChatGPT and Vicuna-13B in the Vicuna Benchmark’s question prompt. Extensive experiments demonstrate that our approach successfully alleviates evaluation bias, resulting in closer alignment with human judgments.
Improving Event Definition Following For Zero-Shot Event Detection
Zefan Cai | Po-Nien Kung | Ashima Suvarna | Mingyu Ma | Hritik Bansal | Baobao Chang | P. Jeffrey Brantingham | Wei Wang | Nanyun Peng
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Zefan Cai | Po-Nien Kung | Ashima Suvarna | Mingyu Ma | Hritik Bansal | Baobao Chang | P. Jeffrey Brantingham | Wei Wang | Nanyun Peng
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Existing approaches on zero-shot event detection usually train models on datasets annotated with known event types, and prompt them with unseen event definitions. These approaches yield sporadic successes, yet generally fall short of expectations.In this work, we aim to improve zero-shot event detection by training models to better follow event definitions. We hypothesize that a diverse set of event types and definitions are the key for models to learn to follow event definitions while existing event extraction datasets focus on annotating many high-quality examples for a few event types. To verify our hypothesis, we construct an automatically generated Diverse Event Definition (DivED) dataset and conduct comparative studies. Our experiments reveal that a large number of event types (200) and diverse event definitions can significantly boost event extraction performance; on the other hand, the performance does not scale with over ten examples per event type.Beyond scaling, we incorporate event ontology information and hard-negative samples during training, further boosting the performance. Based on these findings, we fine-tuned a LLaMA-2-7B model on our DivED dataset, yielding performance that surpasses SOTA large language models like GPT-3.5 across three open benchmarks on zero-shot event detection.
2023
SANTA: Separate Strategies for Inaccurate and Incomplete Annotation Noise in Distantly-Supervised Named Entity Recognition
Shuzheng Si | Zefan Cai | Shuang Zeng | Guoqiang Feng | Jiaxing Lin | Baobao Chang
Findings of the Association for Computational Linguistics: ACL 2023
Shuzheng Si | Zefan Cai | Shuang Zeng | Guoqiang Feng | Jiaxing Lin | Baobao Chang
Findings of the Association for Computational Linguistics: ACL 2023
Distantly-Supervised Named Entity Recognition effectively alleviates the burden of time-consuming and expensive annotation in the supervised setting. But the context-free matching process and the limited coverage of knowledge bases introduce inaccurate and incomplete annotation noise respectively. Previous studies either considered only incomplete one or indiscriminately handle two types of noise with the same strategy. In this paper, we argue that the different causes of two types of noise bring up the requirement of different strategies in model architecture. Therefore, we propose the SANTA to handle these two types of noise separately with (1) Memory-smoothed Focal Loss and Entity-aware KNN to relieve the entity ambiguity problem caused by inaccurate annotation, and (2) Boundary Mixup to alleviate decision boundary shifting problem caused by incomplete annotation and a noise-tolerant loss to improve the model’s robustness. Benefiting from our separate tailored strategies, we confirm in the experiment that the two types of noise are well mitigated.SANTA also achieves a new state-of-the-art on five public datasets.
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- Baobao Chang (常宝宝) 7
- Haozhe Zhao 5
- Shuzheng Si 4
- Junjie Hu 3
- Peiyi Wang (王培懿) 3
- Wen Xiao 3
- Kaikai An 2
- Yunbo Cao 2
- Liang Chen 2
- Liang Chen 2
- Jiuxiang Gu 2
- Binghuai Lin 2
- Tianyu Liu 2
- Tianyu Liu 2
- Nanyun Peng 2
- Shuang Zeng 2
- Minjia Zhang 2
- Hritik Bansal 1
- P. Jeffrey Brantingham 1
- Guoqiang Feng 1
- Bofei Gao 1
- Jiaqi Han 1
- Yufeng He 1
- Helan Hu 1
- Kung-Hsiang Huang 1
- Lingpeng Kong 1
- Parisa Kordjamshidi 1
- Po-Nien Kung 1
- Lei Li 1
- Tingting Liao 1
- Jiaxing Lin 1
- Runji Lin 1
- Shawn Lin 1
- Dayiheng Liu 1
- Qi Liu 1
- Keming Lu 1
- Mingyu Ma 1
- Tianyi Ma 1
- Haoran Meng 1
- Xiangdi Meng 1
- Xuan Ouyang 1
- Haoyi Qiu 1
- Shuhuai Ren 1
- Zhifang Sui (穗志方) 1
- Ashima Suvarna 1
- Ke Wan 1
- Wei Wang 1
- Yuchi Wang 1
- Runxin Xu 1
- Xinyan Velocity Yu 1
- Gang Yuan 1
- Yichi Zhang 1
- Ce Zheng 1
- Xin Zheng 1
- Chang Zhou 1
- Gengze Zhou 1
- Dawei Zhu 1