Xi Yang
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2026
MultivationBench: A Benchmark for Multimodal Sequential Motivation Reasoning
Kawai Chung | Chunkit Chan | Yauwai Yim | Yuxuan Liu | Haochen Shi | Weiqi Wang | Qing Zong | Tianshi Zheng | FU Yixuan | Wong Kai Chung | Hao Liang | Yifan Gao | Xi Yang | Janet Hui-wen Hsiao | Yangqiu Song
Findings of the Association for Computational Linguistics: EMNLP 2026
Kawai Chung | Chunkit Chan | Yauwai Yim | Yuxuan Liu | Haochen Shi | Weiqi Wang | Qing Zong | Tianshi Zheng | FU Yixuan | Wong Kai Chung | Hao Liang | Yifan Gao | Xi Yang | Janet Hui-wen Hsiao | Yangqiu Song
Findings of the Association for Computational Linguistics: EMNLP 2026
Multimodal Large Language Models have sparked significant interest due to their potential for social intelligence; however, their ability to perform sequential motivation reasoning remains insufficiently studied. Existing evaluations predominantly examine static text or isolated visual snapshots, which do not reflect the cumulative nature of real-world behavioral drivers. To address this gap, we introduce MulTivationBench, a benchmark designed to rigorously evaluate multimodal motivation reasoning within story-driven visual narratives. The benchmark builds upon established psychological frameworks—Maslow’s hierarchy and Reiss’s basic desires—and requires models to integrate accumulated multimodal context to infer evolving motivations. Results indicate that MulTivationBench presents a significant challenge: all tested models struggle to maintain consistent motivation reasoning across sequential contexts, revealing a critical disconnect between static recognition capabilities and the dynamic reasoning essential for human-like social understanding.
GrandGuard: Taxonomy, Benchmark, and Safeguards for Elderly-Chatbot Interaction Safety
Changxuan Fan | Xi Yang | Yueyuan Zheng | Bin Zhou | Yuanping Wang | Wenbin Hu | Huihao Jing | Ki Sen Hung | Dazhao Du | Haoran Li | Janet Hui-wen Hsiao | Yangqiu Song
Findings of the Association for Computational Linguistics: ACL 2026
Changxuan Fan | Xi Yang | Yueyuan Zheng | Bin Zhou | Yuanping Wang | Wenbin Hu | Huihao Jing | Ki Sen Hung | Dazhao Du | Haoran Li | Janet Hui-wen Hsiao | Yangqiu Song
Findings of the Association for Computational Linguistics: ACL 2026
As older adults increasingly use LLM-based chatbots for companionship and assistance, a safety gap is emerging. Older adults may face vulnerabilities from social isolation, limited digital literacy, and cognitive decline, yet existing safety benchmarks largely target general harms and overlook elderly-specific risks. For example, a prompt such as “how to repair a ceiling light alone in the dark” may be benign for most users but poses a serious fall risk for older adults with mobility limitations.We introduce GrandGuard, the first comprehensive framework for assessing and mitigating elderly-specific contextual risks in LLM interactions. We develop a three-level taxonomy with 50 fine-grained risk types across mental well-being, financial, medical, toxicity, and privacy domains, grounded in real-world incidents, community discussions, and analysis of stakeholder studies. Using this taxonomy, we construct a benchmark of 10,404 labeled prompts and responses, showing that several leading LLMs mishandle elderly-specific contextual risks in over 50% of cases. We mitigate these failures with two safeguards: a fine-tuned Llama-Guard-3 and a policy-enhanced gpt-oss-safeguard-20b, achieving up to 96.2% and 90.9% unsafe-prompt detection accuracy, respectively. GrandGuard lays the groundwork for AI systems that move beyond general safety to support aging populations.
Steering LLM Viewpoints through Fabricated Evidence Injection
Xi Yang | Chang Liu | Zhenglin Huang | Haoran Li | Weiming Zhang | Jian Weng | Yangqiu Song
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Xi Yang | Chang Liu | Zhenglin Huang | Haoran Li | Weiming Zhang | Jian Weng | Yangqiu Song
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
As chatbots increasingly influence daily decision-making, their potential to produce misleading responses poses substantial risks to users. This paper investigates a critical cognitive vulnerability in LLMs: their tendency to uncritically trust external context when presented with fabricated evidence bearing markers of credibility. We introduce Ghostwriter, a two-phase attack framework that first repackages misleading statements with fabricated rationales, then instruct target LLMs to incorporate these viewpoints when responding to relevant queries. Experiments on BBQ, ToxiGen, and our specialized dataset reveal that commercial LLMs without external safety classifiers remain highly vulnerable, while even frontier classifier-guarded models (e.g., GPT-5.4) reduce but do not eliminate the attack. Building on this, we explore multiple defense strategies, among which a tailored safety policy enables gpt-oss-safeguard to achieve 80.5% detection rate.
GSPR: Aligning LLM Safeguards as Generalizable Safety Policy Reasoners
Haoran Li | Jingru Zeng | Yulin Chen | Huihao Jing | Wenbin Hu | Hao Peng | Haochen Shi | Xi Yang | Ziqian Zeng | Sirui Han | Yangqiu Song
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Haoran Li | Jingru Zeng | Yulin Chen | Huihao Jing | Wenbin Hu | Hao Peng | Haochen Shi | Xi Yang | Ziqian Zeng | Sirui Han | Yangqiu Song
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
As large language models (LLMs) are integrated into numerous applications, LLMs’ safety becomes critical for both application developers and intended users. Currently, great efforts have been made to develop safety benchmarks with fine-grained taxonomies. However, these benchmarks’ taxonomies are disparate with different safety policies. Thus, existing safeguards trained on these benchmarks are either coarse-grained to only distinguish between "safe” and "unsafe,” or constrained by the specified narrow risk taxonomies. To leverage these fine-grained safety policies across multiple safety taxonomies, we propose GSPR, a Generalizable Safety Policy Reasoner to identify unsafe inputs and outputs with violated safety taxonomies and concise explanations. Unlike prior safeguards which only cover a fixed set of risk factors, GSPR incentivizes its reasoning capability with varied safety taxonomies through reinforcement learning. Our GSPR can be trained across multiple safety benchmarks with distinct taxonomies and naturally exhibits powerful generalization ability. We conduct extensive experiments to show that GSPR significantly improves existing safety guardrails’ reasoning capabilities for both safety and category prediction tasks. Moreover, GSPR also achieves the least inference token costs with explanations.
Reflect to Inform: Boosting Multimodal Reasoning via Information-Gain-Driven Verification
Shuai Lv | Chang Liu | Feng Tang | Rui Chen | Yu-Jie Yuan | Aojun Zhou | Kui Zhang | Xi Yang | Yangqiu Song
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Shuai Lv | Chang Liu | Feng Tang | Rui Chen | Yu-Jie Yuan | Aojun Zhou | Kui Zhang | Xi Yang | Yangqiu Song
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Multimodal Large Language Models (MLLMs) achieve strong multimodal reasoning performance, yet we identify a recurring failure mode in long-form generation: as outputs grow longer, models progressively drift away from image evidence and fall back on textual priors, resulting in ungrounded reasoning and hallucinations. Interestingly, Based on attention analysis, we find that MLLMs have a latent capability for late-stage visual verification that is present but not consistently activated. Motivated by this observation, we propose Visual Re-Examination (VRE), a self-evolving training framework that enables MLLMs to autonomously perform visual introspection during reasoning without additional visual inputs. Rather than distilling visual capabilities from a stronger teacher, VRE promotes iterative self-improvement by leveraging the model itself to generate reflection traces, making visual information actionable through information gain. Extensive experiments across diverse multimodal benchmarks demonstrate that VRE consistently improves reasoning accuracy and perceptual reliability, while substantially reducing hallucinations, especially in long-chain settings.
Into the Gray Zone: Domain Contexts Can Blur LLM Safety Boundaries
Ki Sen Hung | Xi Yang | Chang Liu | Haoran Li | Kejiang Chen | Changxuan Fan | Tsun On Kwok | Weiming Zhang | Xiaomeng Li | Yangqiu Song
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Ki Sen Hung | Xi Yang | Chang Liu | Haoran Li | Kejiang Chen | Changxuan Fan | Tsun On Kwok | Weiming Zhang | Xiaomeng Li | Yangqiu Song
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
A central goal of LLM alignment is to balance helpfulness with harmlessness, yet these objectives conflict when the same knowledge serves both legitimate and malicious purposes. This tension is amplified by context-sensitive alignment: we observe that domain-specific contexts (e.g., chemistry) selectively relax defenses for domain-relevant harmful knowledge, while safety-research contexts (e.g., jailbreak studies) trigger broader relaxation spanning all harm categories. To systematically exploit this vulnerability, we propose Jargon, a framework combining safety-research contexts with multi-turn adversarial interactions that achieves attack success rates exceeding 93% across seven frontier models, including GPT-5.2, Claude-4.5, and Gemini-3, substantially outperforming existing methods. Activation space analysis reveals that Jargon queries occupy an intermediate region between benign and harmful inputs, a gray zone where refusal decisions become unreliable. To mitigate this vulnerability, we design a policy-guided safeguard that steers models toward helpful yet harmless responses, and internalize this capability through alignment fine-tuning, reducing attack success rates while preserving helpfulness.
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- Yangqiu Song 6
- Haoran Li 4
- Chang Liu 3
- Changxuan Fan 2
- Janet Hui-wen Hsiao 2
- Wenbin Hu 2
- Ki Sen Hung 2
- Huihao Jing 2
- Haochen Shi 2
- Weiming Zhang 2
- Chunkit Chan 1
- Kejiang Chen 1
- Rui Chen 1
- Yulin Chen 1
- Kawai Chung 1
- Wong Kai Chung 1
- Dazhao Du 1
- Yifan Gao 1
- Sirui Han 1
- Zhenglin Huang 1
- Tsun On Kwok 1
- Xiaomeng Li 1
- Hao Liang 1
- Yuxuan Liu 1
- Shuai Lv 1
- Hao Peng 1
- Feng Tang 1
- Weiqi Wang 1
- Yuanping Wang 1
- Jian Weng 1
- Yauwai Yim 1
- FU Yixuan 1
- Yu-Jie Yuan 1
- Jingru Zeng 1
- Ziqian Zeng 1
- Kui Zhang 1
- Tianshi Zheng 1
- Yueyuan Zheng 1
- Aojun Zhou 1
- Bin Zhou 1
- Qing Zong 1