Yifei Wang
Also published as: YiFei Wang
2026
Beyond Cross-Modal Alignment: Measuring and Leveraging Modality Gap in Vision-Language Models
Hanqi Yan | Xiangxiang Cui | Lu Yin | Jindong Gu | Paul Pu Liang | Yulan He | Yifei Wang
Findings of the Association for Computational Linguistics: ACL 2026
Hanqi Yan | Xiangxiang Cui | Lu Yin | Jindong Gu | Paul Pu Liang | Yulan He | Yifei Wang
Findings of the Association for Computational Linguistics: ACL 2026
The success of vision-language models is primarily attributed to effective cross-modal alignment between vision and language. However, modality gaps persist even in well-aligned models and may be necessary for human perception, as evidenced by modality-specific phenomena such as visual texture and linguistic tone. These observations motivate us to computationally measure and leverage modality gaps to explore their utility in downstream applications. In this paper, we introduce the Modality Dominance Score (MDS), which attributes multimodal features to specific modalities by categorizing them as vision-dominant, language-dominant, or cross-modal. We then propose automatic interpretability metrics to evaluate these modality-specific features in a scalable manner. Finally, we demonstrate how the identified modality-specific features enable training-free probing and editing methods for understanding model perception across genders, generating adversarial examples, and controlling text-to-image generation. Combined with task-agnostic interpretability tools, our work provides a systematic framework for analyzing and efficiently controlling multimodal models.
R3: End-to-End Reasoning-based Planning for Multi-step Retrosynthesis via Reinforcement Learning
YiFei Wang | Qizhi Pei | Jiangtao Feng | Yuntian Shi | Yi Duan | Lihao Wang | Lei Bai | Lijun Wu | Wei-Ying Ma | Hao Zhou
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
YiFei Wang | Qizhi Pei | Jiangtao Feng | Yuntian Shi | Yi Duan | Lihao Wang | Lei Bai | Lijun Wu | Wei-Ying Ma | Hao Zhou
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Multi-step retrosynthetic planning is a fundamental challenge in organic chemistry, traditionally modeled as a combinatorial search problem guided by single-step prediction models. However, this search-centric paradigm often disconnects from the explicit chemical reasoning processes employed by human experts. In this paper, we propose R3 (Reinforced Reasoning Retrosynthesis), a novel framework that reformulates this task as end-to-end generative reasoning. Instead of traversing a search tree, R3 simulates the problem-solving logic of chemists to directly generate complete synthetic pathways. To achieve this, we initialize the model with domain knowledge and employ end-to-end Reinforcement Learning (RL) to optimize the entire planning policy. Experimental results on Retrobench show that R3 achieves a state-of-the-art Top-1 accuracy of 43.7%, demonstrating that generative reasoning offers a superior alternative to traditional search algorithms in solving complex retrosynthetic problems.
2025
POSITION BIAS MITIGATES POSITION BIAS: Mitigate Position Bias Through Inter-Position Knowledge Distillation
Yifei Wang | Feng Xiong | Yong Wang | Linjing Li | Xiangxiang Chu | Daniel Dajun Zeng
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Yifei Wang | Feng Xiong | Yong Wang | Linjing Li | Xiangxiang Chu | Daniel Dajun Zeng
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Positional bias (PB), manifesting as non-uniform sensitivity across different contextual locations, significantly impairs long-context comprehension and processing capabilities. Previous studies have addressed PB either by modifying the underlying architectures or by employing extensive contextual awareness training. However, the former approach fails to effectively eliminate the substantialperformance disparities, while the latter imposes significant data and computational overhead. To address PB effectively, we introduce Pos2Distill, a position to position knowledge distillation framework. Pos2Distill transfers the superior capabilities from advantageous positions to less favorable ones, thereby reducing the huge performance gaps. The conceptual principle is to leverage the inherent, position-induced disparity to counteract the PB itself. We identify distinct manifestations of PB under retrieval and reasoning paradigms, thereby designing two specialized instantiations: Pos2Distill-R1 and Pos2Distill-R2 respectively, both grounded in this core principle. By employing the Pos2Distill approach, we achieve enhanced uniformity and significant performance gains across all contextual positions in long-context retrieval and reasoning tasks. Crucially, both specialized systems exhibit strong cross-task generalization mutually, while achieving superior performance on their respective tasks.
Multi-Agent Collaboration via Cross-Team Orchestration
Zhuoyun Du | Chen Qian | Wei Liu | Zihao Xie | YiFei Wang | Rennai Qiu | Yufan Dang | Weize Chen | Cheng Yang | Ye Tian | Xuantang Xiong | Lei Han
Findings of the Association for Computational Linguistics: ACL 2025
Zhuoyun Du | Chen Qian | Wei Liu | Zihao Xie | YiFei Wang | Rennai Qiu | Yufan Dang | Weize Chen | Cheng Yang | Ye Tian | Xuantang Xiong | Lei Han
Findings of the Association for Computational Linguistics: ACL 2025
Large Language Models (LLMs) have significantly impacted various domains, especially through organized LLM-driven autonomous agents. A representative scenario is in software development, where agents can collaborate in a team like humans, following predefined phases to complete sub-tasks sequentially. However, for an agent team, each phase yields only one possible outcome. This results in the completion of only one development chain, thereby losing the opportunity to explore multiple potential decision paths within the solution space. Consequently leading to suboptimal results or extensive trial and error. To address this, we introduce Cross-Team Orchestration (Croto), a scalable multi-team framework that enables orchestrated teams to jointly propose various task-oriented solutions and interact with their insights in a self-independence while cross-team collaboration environment for superior solutions generation. Experiments reveal a notable increase in software quality compared to state-of-the-art baselines. We further tested our framework on story generation tasks, which demonstrated a promising generalization ability of our framework in other domains. The code and data is available at https://github.com/OpenBMB/ChatDev/tree/macnet
CCL25-Eval任务9总结报告:中医辨证辨病及中药处方生成评测
Cong Wang | Zhizhuo Zhao | Yishuo Li | Hongjiao Guan | Yifei Wang | Zhenyu Li | Wenpeng Lu
Proceedings of the 24th China National Conference on Computational Linguistics (CCL 2025)
Cong Wang | Zhizhuo Zhao | Yishuo Li | Hongjiao Guan | Yifei Wang | Zhenyu Li | Wenpeng Lu
Proceedings of the 24th China National Conference on Computational Linguistics (CCL 2025)
"中医辨证辨病及中药处方生成评测任务专注于中医“辨证论治”。该任务由齐鲁工业大学(山东省科学院)与山东中医药大学附属医院联合发起,基于真实病历构建了中医“辨证论治”全流程公开数据集TCM-TBOSD,覆盖10类中医证型、4类中医疾病及381种常见中药。评测任务设立两个子任务:中医多标签辨证辨病与中药处方推荐,旨在系统评估大模型在中医诊疗全过程中的建模与推理能力。本次评测收到了学术界与产业界的广泛关注,评测共吸引123支队伍参与,35支队伍晋级复赛,最终提交了8份高质量技术报告。评测结果表明,大语言模型在中医任务中展现出良好的适应性与发展潜力,为中医智能化提供了可行路径与技术参考。详细信息可以从网址查看我们的评测任务。"
Uncertainty Unveiled: Can Exposure to More In-context Examples Mitigate Uncertainty for Large Language Models?
Yifei Wang | Yu Sheng | Linjing Li | Daniel Dajun Zeng
Findings of the Association for Computational Linguistics: ACL 2025
Yifei Wang | Yu Sheng | Linjing Li | Daniel Dajun Zeng
Findings of the Association for Computational Linguistics: ACL 2025
Recent advances in handling long sequences have unlocked new possibilities for long-context in-context learning (ICL). While existing research predominantly focuses on performance gains driven by additional in-context examples, the impact on the trustworthiness of generated responses remains underexplored. This paper addresses this gap by investigating how increased examples influence predictive uncertainty—an essential aspect in trustworthiness. We begin by systematically quantifying uncertainty across different “shot” configurations in ICL, emphasizing the role of example quantity. Through uncertainty decomposition, we introduce a novel perspective on performance enhancement, focusing on epistemic uncertainty (EU). Our results reveal that additional examples reduce total uncertainty in both simple and complex tasks by injecting task-specific knowledge, thereby diminishing EU and enhancing performance. For complex tasks, these advantages emerge only after addressing the increased noise and uncertainty associated with longer inputs. Finally, we investigate the progression of internal confidence across layers, uncovering the underlying mechanisms that drive the reduction in uncertainty.
HS-STaR: Hierarchical Sampling for Self-Taught Reasoners via Difficulty Estimation and Budget Reallocation
Feng Xiong | Hongling Xu | Yifei Wang | Runxi Cheng | Yong Wang | Xiangxiang Chu
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Feng Xiong | Hongling Xu | Yifei Wang | Runxi Cheng | Yong Wang | Xiangxiang Chu
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Self-taught reasoners (STaRs) enhance the mathematical reasoning abilities of large language models (LLMs) by leveraging self-generated responses for self-training. Recent studies have incorporated reward models to guide response selection or decoding, aiming to obtain higher-quality data. However, they typically allocate a uniform sampling budget across all problems, overlooking the varying utility of problems at different difficulty levels. In this work, we conduct an empirical study and find that problems near the boundary of the LLM’s reasoning capability offer significantly greater learning utility than both easy and overly difficult ones. To identify and exploit such problems, we propose HS-STaR, a Hierarchical Sampling framework for Self-Taught Reasoners. Given a fixed sampling budget, HS-STaR first performs lightweight pre-sampling with a reward-guided difficulty estimation strategy to efficiently identify boundary-level problems. Subsequently, it dynamically reallocates the remaining budget toward these high-utility problems during a re-sampling phase, maximizing the generation of valuable training data. Extensive experiments across multiple reasoning benchmarks and backbone LLMs demonstrate that HS-STaR significantly outperforms other baselines without requiring additional sampling budget.
2024
Experiential Co-Learning of Software-Developing Agents
Chen Qian | Yufan Dang | Jiahao Li | Wei Liu | Zihao Xie | YiFei Wang | Weize Chen | Cheng Yang | Xin Cong | Xiaoyin Che | Zhiyuan Liu | Maosong Sun
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Chen Qian | Yufan Dang | Jiahao Li | Wei Liu | Zihao Xie | YiFei Wang | Weize Chen | Cheng Yang | Xin Cong | Xiaoyin Che | Zhiyuan Liu | Maosong Sun
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Recent advancements in large language models (LLMs) have brought significant changes to various domains, especially through LLM-driven autonomous agents. A representative scenario is in software development, where LLM agents demonstrate efficient collaboration, task division, and assurance of software quality, markedly reducing the need for manual involvement. However, these agents frequently perform a variety of tasks independently, without benefiting from past experiences, which leads to repeated mistakes and inefficient attempts in multi-step task execution. To this end, we introduce Experiential Co-Learning, a novel LLM-agent learning framework in which instructor and assistant agents gather shortcut-oriented experiences from their historical trajectories and use these past experiences for future task execution. The extensive experiments demonstrate that the framework enables agents to tackle unseen software-developing tasks more effectively. We anticipate that our insights will guide LLM agents towards enhanced autonomy and contribute to their evolutionary growth in cooperative learning. The code and data are available at https://github.com/OpenBMB/ChatDev.
Unveiling Factual Recall Behaviors of Large Language Models through Knowledge Neurons
Yifei Wang | Yuheng Chen | Wanting Wen | Yu Sheng | Linjing Li | Daniel Dajun Zeng
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Yifei Wang | Yuheng Chen | Wanting Wen | Yu Sheng | Linjing Li | Daniel Dajun Zeng
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
In this paper, we investigate whether Large Language Models (LLMs) actively recall or retrieve their internal repositories of factual knowledge when faced with reasoning tasks. Through an analysis of LLMs’ internal factual recall at each reasoning step via Knowledge Neurons, we reveal that LLMs fail to harness the critical factual associations under certain circumstances. Instead, they tend to opt for alternative, shortcut-like pathways to answer reasoning questions. By manually manipulating the recall process of parametric knowledge in LLMs, we demonstrate that enhancing this recall process directly improves reasoning performance whereas suppressing it leads to notable degradation. Furthermore, we assess the effect of Chain-of-Thought (CoT) prompting, a powerful technique for addressing complex reasoning tasks. Our findings indicate that CoT can intensify the recall of factual knowledge by encouraging LLMs to engage in orderly and reliable reasoning. Furthermore, we explored how contextual conflicts affect the retrieval of facts during the reasoning process to gain a comprehensive understanding of the factual recall behaviors of LLMs. Code and data will be available soon.
BadAgent: Inserting and Activating Backdoor Attacks in LLM Agents
Yifei Wang | Dizhan Xue | Shengjie Zhang | Shengsheng Qian
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Yifei Wang | Dizhan Xue | Shengjie Zhang | Shengsheng Qian
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
With the prosperity of large language models (LLMs), powerful LLM-based intelligent agents have been developed to provide customized services with a set of user-defined tools. State-of-the-art methods for constructing LLM agents adopt trained LLMs and further fine-tune them on data for the agent task. However, we show that such methods are vulnerable to our proposed backdoor attacks named BadAgent on various agent tasks, where a backdoor can be embedded by fine-tuning on the backdoor data. At test time, the attacker can manipulate the deployed LLM agents to execute harmful operations by showing the trigger in the agent input or environment. To our surprise, our proposed attack methods are extremely robust even after fine-tuning on trustworthy data. Though backdoor attacks have been studied extensively in natural language processing, to the best of our knowledge, we could be the first to study them on LLM agents that are more dangerous due to the permission to use external tools. Our work demonstrates the clear risk of constructing LLM agents based on untrusted LLMs or data. Our code is public at https://github.com/DPamK/BadAgent
Encourage or Inhibit Monosemanticity? Revisit Monosemanticity from a Feature Decorrelation Perspective
Hanqi Yan | Yanzheng Xiang | Guangyi Chen | Yifei Wang | Lin Gui | Yulan He
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Hanqi Yan | Yanzheng Xiang | Guangyi Chen | Yifei Wang | Lin Gui | Yulan He
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
To better interpret the intrinsic mechanism of large language models (LLMs), recent studies focus on monosemanticity on its basic units. A monosemantic neuron is dedicated to a single and specific concept, which forms a one-to-one correlation between neurons and concepts. Despite extensive research in monosemanticity probing, it remains unclear whether monosemanticity is beneficial or harmful to model capacity. To explore this question, we revisit monosemanticity from the feature decorrelation perspective and advocate for its encouragement. We experimentally observe that the current conclusion by (CITATION), which suggests that decreasing monosemanticity enhances model performance, does not hold when the model changes. Instead, we demonstrate that monosemanticity consistently exhibits a positive correlation with model capacity, in the preference alignment process. Consequently, we apply feature correlation as a proxy for monosemanticity and incorporate a feature decorrelation regularizer into the dynamic preference optimization process. The experiments show that our method not only enhances representation diversity and activation sparsity but also improves preference alignment performance.
2020
Train Once, and Decode As You Like
Chao Tian | Yifei Wang | Hao Cheng | Yijiang Lian | Zhihua Zhang
Proceedings of the 28th International Conference on Computational Linguistics
Chao Tian | Yifei Wang | Hao Cheng | Yijiang Lian | Zhihua Zhang
Proceedings of the 28th International Conference on Computational Linguistics
In this paper we propose a unified approach for supporting different generation manners of machine translation, including autoregressive, semi-autoregressive, and refinement-based non-autoregressive models. Our approach works by repeatedly selecting positions and generating tokens at these selected positions. After being trained once, our approach achieves better or competitive translation performance compared with some strong task-specific baseline models in all the settings. This generalization ability benefits mainly from the new training objective that we propose. We validate our approach on the WMT’14 English-German and IWSLT’14 German-English translation tasks. The experimental results are encouraging.
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- Linjing Li 3
- Daniel Dajun Zeng 3
- Weize Chen 2
- Xiangxiang Chu 2
- Yufan Dang 2
- Yulan He 2
- Wei Liu 2
- Yu Sheng 2
- Yong Wang 2
- Zihao Xie 2
- Feng Xiong 2
- Hanqi Yan 2
- Lei Bai 1
- Xiaoyin Che 1
- Yuheng Chen 1
- Guangyi Chen 1
- Hao Cheng 1
- Runxi Cheng 1
- Xin Cong 1
- Xiangxiang Cui 1
- Zhuoyun Du 1
- Yi Duan 1
- Jiangtao Feng 1
- Jindong Gu 1
- Hongjiao Guan 1
- Lin Gui 1
- Lei Han 1
- Jiahao Li 1
- Yishuo Li 1
- Zhenyu Li 1
- Yijiang Lian 1
- Paul Pu Liang 1
- Zhiyuan Liu 1
- Wenpeng Lu 1
- Wei-Ying Ma 1
- Qizhi Pei 1
- Chen Qian 1
- Shengsheng Qian 1
- Chen Qian 1
- Rennai Qiu 1
- Yuntian Shi 1
- Maosong Sun (孙茂松) 1
- Chao Tian 1
- Ye Tian 1
- Cong Wang 1
- Lihao Wang 1
- Wanting Wen 1
- Lijun Wu 1
- Yanzheng Xiang 1
- Xuantang Xiong 1
- Hongling Xu 1
- Dizhan Xue 1
- Cheng Yang 1
- Cheng Yang 1
- Lu Yin 1
- Zhihua Zhang 1
- Shengjie Zhang 1
- Zhizhuo Zhao 1
- Hao Zhou 1