Line of Sight: On Linear Representations in VLLMs
On the map: Mechanistic interpretability → Interpreting vision and multimodal models
Abstract (arXiv)
Language models can be equipped with multimodal capabilities by fine-tuning on embeddings of visual inputs. But how do such multimodal models represent images in their hidden activations? We explore representations of image concepts within LlaVA-Next, a popular open-source VLLM. We find a diverse set of ImageNet classes represented via linearly decodable features in the residual stream. We show that the features are causal by performing targeted edits on the model output. In order to increase the diversity of the studied linear features, we train multimodal Sparse Autoencoders (SAEs), creating a highly interpretable dictionary of text and image features. We find that although model representations across modalities are quite disjoint, they become increasingly shared in deeper layers.
Key facts. Cited by 6 papers in the map (data through 14 Oct 2026). Placed in Interpreting vision and multimodal models, one of 13 directions in Mechanistic interpretability. Builds on 22 of its 41 references that are in the map. First posted on arXiv 5 Jun 2025.
Builds on
22 of 41 references.
References · 22
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10 more
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Built on by
Citing papers per year: 2025: 2; 2026: 4.
6 papers.
- 2025Head Pursuit: Probing Attention Specialization in Multimodal Transformerscited by 17
- 2025SAVE: Sparse Autoencoder-Driven Visual Information Enhancement for Mitigating Object Hallucinationcited by 5
- 2026Probing Visual Concepts in Lightweight Vision-Language Models for Automated Drivingcited by 3
- 2026Language Models Can Explain Visual Features via Steeringcited by 2
- 2026Uncovering and Shaping the Latent Representation of 3D Scene Topology in Vision-Language Modelscited by 1
- 2026Visual concept ranking uncovers medical shortcuts used by large multimodal modelscited by 0
- 2026Uncovering and Shaping the Latent Representation of 3D Scene Topology in Vision-Language Models8 May 2026
- 2026Language Models Can Explain Visual Features via Steering23 Mar 2026
- 2026Probing Visual Concepts in Lightweight Vision-Language Models for Automated Driving6 Mar 2026
- 2026Visual concept ranking uncovers medical shortcuts used by large multimodal models4 Feb 2026
- 2025SAVE: Sparse Autoencoder-Driven Visual Information Enhancement for Mitigating Object Hallucination8 Dec 2025
- 2025Head Pursuit: Probing Attention Specialization in Multimodal Transformers24 Oct 2025
Similar, not cited
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- 2026Extraction and Analysis of Multimodal Concepts in Vision Language Models through Sparse Autoencoders
- 2026Cascaded Sparse Autoencoders Learn Multi-Level Visual Concepts in Multimodal LLMs
- 2025Interpreting the linear structure of vision-language model embedding spaces
- 2025How Visual Representations Map to Language Feature Space in Multimodal LLMs
- 2024The Narrow Gate: Localized Image-Text Communication in Native Multimodal Models
- 2024Enhancing Few-Shot Vision-Language Classification with Large Multimodal Model Features
- 2025Explaining How Visual, Textual and Multimodal Encoders Share Concepts
- 2025SAE-V: Interpreting Multimodal Models for Enhanced Alignment