VERHallu: Evaluating and Mitigating Event Relation Hallucination in Video Large Language Models

Fuente: arXiv
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Main Authors: Zhang, Zefan, Zhu, Kehua, Jiang, Shijie, Lu, Hongyuan, Sun, Shengkai, Bai, Tian
Format: Preprint
Published: 2026
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author Zhang, Zefan
Zhu, Kehua
Jiang, Shijie
Lu, Hongyuan
Sun, Shengkai
Bai, Tian
author_facet Zhang, Zefan
Zhu, Kehua
Jiang, Shijie
Lu, Hongyuan
Sun, Shengkai
Bai, Tian
contents Video Large Language Models (VideoLLMs) exhibit various types of hallucinations. Existing research has primarily focused on hallucinations involving the presence of events, objects, and scenes in videos, while largely neglecting event relation hallucination. In this paper, we introduce a novel benchmark for evaluating the Video Event Relation Hallucination, named VERHallu. This benchmark focuses on causal, temporal, and subevent relations between events, encompassing three types of tasks: relation classification, question answering, and counterfactual question answering, for a comprehensive evaluation of event relation hallucination. Additionally, it features counterintuitive video scenarios that deviate from typical pretraining distributions, with each sample accompanied by human-annotated candidates covering both vision-language and pure language biases. Our analysis reveals that current state-of-the-art VideoLLMs struggle with dense-event relation reasoning, often relying on prior knowledge due to insufficient use of frame-level cues. Although these models demonstrate strong grounding capabilities for key events, they often overlook the surrounding subevents, leading to an incomplete and inaccurate understanding of event relations. To tackle this, we propose a Key-Frame Propagating (KFP) strategy, which reallocates frame-level attention within intermediate layers to enhance multi-event understanding. Experiments show it effectively mitigates the event relation hallucination without affecting inference speed.
format Preprint
id arxiv_https___arxiv_org_abs_2601_10010
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle VERHallu: Evaluating and Mitigating Event Relation Hallucination in Video Large Language Models
Zhang, Zefan
Zhu, Kehua
Jiang, Shijie
Lu, Hongyuan
Sun, Shengkai
Bai, Tian
Computer Vision and Pattern Recognition
Artificial Intelligence
Video Large Language Models (VideoLLMs) exhibit various types of hallucinations. Existing research has primarily focused on hallucinations involving the presence of events, objects, and scenes in videos, while largely neglecting event relation hallucination. In this paper, we introduce a novel benchmark for evaluating the Video Event Relation Hallucination, named VERHallu. This benchmark focuses on causal, temporal, and subevent relations between events, encompassing three types of tasks: relation classification, question answering, and counterfactual question answering, for a comprehensive evaluation of event relation hallucination. Additionally, it features counterintuitive video scenarios that deviate from typical pretraining distributions, with each sample accompanied by human-annotated candidates covering both vision-language and pure language biases. Our analysis reveals that current state-of-the-art VideoLLMs struggle with dense-event relation reasoning, often relying on prior knowledge due to insufficient use of frame-level cues. Although these models demonstrate strong grounding capabilities for key events, they often overlook the surrounding subevents, leading to an incomplete and inaccurate understanding of event relations. To tackle this, we propose a Key-Frame Propagating (KFP) strategy, which reallocates frame-level attention within intermediate layers to enhance multi-event understanding. Experiments show it effectively mitigates the event relation hallucination without affecting inference speed.
title VERHallu: Evaluating and Mitigating Event Relation Hallucination in Video Large Language Models
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2601.10010