Chart-EARL: Improving Chart Reasoning of Vision LLMs via Early Anchoring in Reinforcement Learning

Gongyao Jiang, Qiong Luo


Abstract
Chart reasoning poses a significant challenge for Vision Large Language Models (VLLMs). While Reinforcement Learning (RL) has emerged as a promising solution, existing outcome-based RL methods overlook intermediate errors, whereas process-based approaches remain difficult in verifying abstract logical steps. We therefore analyze chart-reasoning failures to identify an intermediate supervision signal that is both relevant to the task and amenable to objective verification. Our pilot study suggests that early visual-perception errors constitute a prominent source of failure in the chart-reasoning setting. Guided by this insight, we propose Chart-EARL, which constructs verifiable early visual anchors for targeted chart-reasoning supervision. We first build a structured training corpus that explicitly decouples visual perception from logical deduction. Building upon this structure, our approach optimizes the model with rewards for both accurate extraction of descriptive visual features and final-answer correctness. This strategy provides direct and verifiable feedback on early visual grounding while keeping supervision on the final reasoning objective. Experiments show clear performance improvements on complex chart reasoning benchmarks.
Anthology ID:
2026.findings-emnlp.1591
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
33872–33889
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1591/
DOI:
10.18653/2026.findings-emnlp.1591
Bibkey:
Cite (ACL):
Gongyao Jiang and Qiong Luo. 2026. Chart-EARL: Improving Chart Reasoning of Vision LLMs via Early Anchoring in Reinforcement Learning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 33872–33889, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Chart-EARL: Improving Chart Reasoning of Vision LLMs via Early Anchoring in Reinforcement Learning (Jiang & Luo, Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.1591.pdf