Skip to content
Preprint

What Does Prompt Learning Change? -A Natural-Language Concept Analysis of Vision-Language Models

Aug 2026 · 0 citations · 36 references
Computer Science

TL;DR

This work presents PromptSpLiCE, a post-hoc method that expresses each class-conditioned text embedding as a sparse combination of concepts from a fixed natural-language dictionary, using the same dictionary before and after prompt learning to compare changes in their concept profiles.

Abstract

Prompt learning adapts vision-language models such as CLIP by optimizing continuous prompt vectors, but the learned prompts are difficult to interpret in natural language. We present PromptSpLiCE, a post-hoc method that expresses each class-conditioned text embedding as a sparse combination of concepts from a fixed natural-language dictionary. Using the same dictionary before and after prompt learning allows us to compare changes in their concept profiles. We evaluate PromptSpLiCE on CoOp, a representative prompt-learning method, across 11 image-classification datasets. The concept profiles change substantially: on average, only 1.6 of the initial top-10 concepts remain in the top 10 after learning. Across datasets, profile change is positively associated with accuracy gain. We also derive a local gradient expression that provides geometric intuition for why image-aligned concept directions distinct from the current prompt can have greater loss sensitivity.

View source

Similar papers

Preprint Aug 2026

SAM3-LoRA: Parameter-Efficient Adaptation of a Concept-Promptable Foundation Model for Multi-Class Structural Defect Segmentation

Promptable segmentation foundation models such as SAM3 accept an open-vocabulary text concept and return every instance matching it, but adapting them to a specialized domain by full fine-tuning is computationally prohibitive for the organizations that would benefit most. This study applies Low-Rank Adaptation (LoRA) to SAM3 for multi-class structural defect segmentation and examines both how such a model can be supervised from conventional annotation and whether the resulting efficiency gain transfers across datasets. Two contributions are methodological. First, we describe a supervision procedure that trains a concept-promptable model directly from COCO-style class-labeled instance segmentation by using the category name itself as the prompt, requiring no prompt templates, no synonym expansion, and no learned class embeddings. Second, we identify and mitigate a failure mode specific to this setting: because a conventional annotation file yields positive prompts exclusively, the model's presence prediction decouples from the text condition and degenerates into responding to any prompt, a collapse that is invisible to every metric computed on positive prompts alone. Exhaustive hard-negative prompting, in which every dataset category absent from an image is issued as a zero-detection query, addresses this at no annotation cost. Two adapter placements were compared under an identical protocol, updating 0.121% and 1.341% of model parameters. On a purpose-built tunnel lining dataset, pixel intersection-over-union improved from 0.017 to 0.338 and instance-level recall from 0.375 to 0.672; on the independent public Structural Defects Dataset, from 0.017 to 0.855 and from 0.574 to 1.000. Improvements were directionally consistent across ten metrics on both datasets, and the largest per-category gains occurred precisely where zero-shot competence was absent.

P. Malaisree, S. Youwai, S. Janrungautai et al. · 0 citations
Preprint Jul 2026

C-GAP: Class-Aware and Online Prompting Improves Vision-Language Models on Imbalanced Classes

This work introduces C-GAP Caption-Guided Augmentation and Prompting), a detector-agnostic, annotation-free framework that operates in two phases, and establishes a composite caption baseline combining per-image scene descriptions with class-quantity context, which is shown to outperforms scene-description only or class-quantity-only prompts across multiple open-vocabulary architectures and benchmarks.

F. Fernández, A. Jahangiri, S. Sekeh · 0 citations
Jul 2026

Visual Distribution Anchoring for Efficient Prompt Tuning

This work proposes VDA (Visual Distribution Anchoring), a training-free target adaptation framework that augments a frozen semantic classifier with class-level visual prototypes estimated offline from an unlabeled target pool, and shows that class-specific partitioning drives gains and that visually local pseudo-label errors can remain useful despite being class-incorrect.

Pouya Parsa, Raoof Zare Moayedi, Seongjin Choi · 0 citations
Aug 2026

Instructing the Learning of Language Model with the Token Interpretation to Improve Language Understanding

Pretrained language models (PLMs) have established state-of-the-art performance across diverse natural language understanding (NLU) tasks. This study reveals that seman-tic-rich explanations of lexical units can effectively guide PLM learning processes. We propose a novel language understanding enhancement method with token interpretation (LUETI) that addresses two critical limitations in conventional PLMs: Incomplete token semantics caused by isolated contextual learning and insufficient semantic encoding in embedding matrices. LUETI operates through dual mechanisms, augmenting token represen-tations by integrating hidden states with corresponding token interpretations and refining embedding spaces using interpretation-derived semantic vectors for token prediction. LUETI, which is implemented as a plug-in module for standard architectures, demonstrates significant improvements on BERT and GLM, achieving average performance gains of 3.36% and 4.87% respectively on the SuperGLUE benchmark with equivalent parameters and training data. Note that LUETI-equipped models attain comparable performance to baseline PLMs using only 60% of pretraining data. Findings establish token interpretation as a computationally efficient but semantically powerful enhancement strategy for language model pretraining.

Tianyi Chen, Yashen Wang, Huan Chang et al. · 0 citations
Open access 2026

Leveraging Task-Adaptive Continual Pre-Training to Enhance the Classification Ability of Language Models

This study presents a systematic empirical investigation of task-adaptive continual pre-training (TAPT), introduced by Gururangan et al., for Turkish language understanding, with a particular focus on the effect of the masked-language-modeling rate.

Murat Aydoğan, Savas Yildirim, Tuǧba Dalyan · 0 citations
Open access 2026

UniRS-Instruct: A Principle-Guided Unified Instruction-Following Dataset for Remote Sensing Understanding

UniRS-Instruct is presented, a high-quality, diversified, and unified multimodal instruction-following dataset for RSI understanding that unifies diverse tasks, including image captioning, visual question answering, visual grounding, and region-level captioning, into a consistent format.

Linrui Xu, Yuhan Wang, Ling Zhao et al. · 0 citations

We use cookies to run the site and, with your consent, for analytics and to show ads. See our Cookie Policy.