Exploring Memorization in Fine-tuned Language Models
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Abstract (arXiv)
Large language models (LLMs) have shown great capabilities in various tasks but also exhibited memorization of training data, raising tremendous privacy and copyright concerns. While prior works have studied memorization during pre-training, the exploration of memorization during fine-tuning is rather limited. Compared to pre-training, fine-tuning typically involves more sensitive data and diverse objectives, thus may bring distinct privacy risks and unique memorization behaviors. In this work, we conduct the first comprehensive analysis to explore language models' (LMs) memorization during fine-tuning across tasks. Our studies with open-sourced and our own fine-tuned LMs across various tasks indicate that memorization presents a strong disparity among different fine-tuning tasks. We provide an intuitive explanation of this task disparity via sparse coding theory and unveil a strong correlation between memorization and attention score distribution.
Key facts. Cited by 45 papers in the map (data through 14 Oct 2026). Builds on 26 of its 33 references that are in the map. First posted on arXiv 10 Oct 2023.
Builds on
26 of 33 references.
References · 26
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14 more
- 2022Constitutional AI: Harmlessness from AI Feedbackcited by 3,050
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- 2020Extracting Training Data from Large Language Modelscited by 2,189
- 2019SciBERT: A Pretrained Language Model for Scientific Textcited by 1,414
- 2022Quantifying Memorization Across Neural Language Modelscited by 763
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- 2021Deduplicating Training Data Makes Language Models Bettercited by 714
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- 2022Memorization in NLP Fine-tuning Methodscited by 45
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Citing papers per year: 2023: 1; 2024: 14; 2025: 19; 2026: 11.
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- 2024The Good and The Bad: Exploring Privacy Issues in Retrieval-Augmented Generation (RAG)cited by 159
- 2024SoK: Membership Inference Attacks on LLMs are Rushing Nowhere (and How to Fix It)cited by 59
- 2024Copyright Protection in Generative AI: A Technical Perspectivecited by 38
- 2024On the Impact of Fine-Tuning on Chain-of-Thought Reasoningcited by 32
- 2024Undesirable Memorization in Large Language Models: A Surveycited by 29
- 2023DPZero: Private Fine-Tuning of Language Models without Backpropagationcited by 26
- 2024Unlocking Memorization in Large Language Models with Dynamic Soft Promptingcited by 21
- 2024KBLaM: Knowledge Base augmented Language Modelcited by 16
- 2024Measuring memorization in RLHF for code completioncited by 13
- 2025Privacy Ripple Effects from Adding or Removing Personal Information in Language Model Trainingcited by 10
- 2025Privacy-Aware RAG: Secure and Isolated Knowledge Retrievalcited by 10
- 2025The Landscape of Memorization in LLMs: Mechanisms, Measurement, and Mitigationcited by 10
33 more
- 2024The Fault in our Stars: Quality Assessment of Code Generation Benchmarkscited by 9
- 2024Generalisation First, Memorisation Second? Memorisation Localisation for Natural Language Classification Taskscited by 9
- 2025Mitigating Memorization in LLMs using Activation Steeringcited by 8
- 2024Self-Comparison for Dataset-Level Membership Inference in Large (Vision-)Language Modelscited by 7
- 2025Mitigating Unintended Memorization with LoRA in Federated Learning for LLMscited by 7
- 2026Window-based Membership Inference Attacks Against Fine-tuned Large Language Modelscited by 7
- 2025Large Language Models Penetration in Scholarly Writing and Peer Reviewcited by 6
- 2025Detecting Data Contamination from Reinforcement Learning Post-training for Large Language Modelscited by 6
- 2024Retrieval Augmented Thought Process for Private Data Handling in Healthcarecited by 5
- 2025Memorization in Large Language Models in Medicine: Prevalence, Characteristics, and Implicationscited by 5
- 2026Membership Inference Attacks Against Fine-tuned Diffusion Language Modelscited by 5
- 2025Too Big to Think: Capacity, Memorization, and Generalization in Pre-Trained Transformerscited by 4
- 2025How Much Do Code Language Models Remember? An Investigation on Data Extraction Attacks before and after Fine-tuningcited by 3
- 2025Leaner Training, Lower Leakage: Revisiting Memorization in LLM Fine-Tuning with LoRAcited by 3
- 2025Tab-MIA: A Benchmark Dataset for Membership Inference Attacks on Tabular Data in LLMscited by 3
- 2024Efficient and Private: Memorisation under differentially private parameter-efficient fine-tuning in language modelscited by 2
- 2025Mirage of Mastery: Memorization Tricks LLMs into Artificially Inflated Self-Knowledgecited by 2
- 2025Direct Token Optimization: A Self-contained Approach to Large Language Model Unlearningcited by 2
- 2026Memorization Dynamics in Knowledge Distillation for Language Modelscited by 2
- 2026Benchmarking Knowledge-Extraction Attack and Defense on Retrieval-Augmented Generationcited by 2
- 2025LexiMark: Robust Watermarking via Lexical Substitutions to Enhance Membership Verification of an LLM's Textual Training Datacited by 1
- 2025Exploring Cross-Client Memorization of Training Data in Large Language Models for Federated Learningcited by 1
- 2025Breaking Memorization Barriers in LLM Code Fine-Tuning via Information Bottleneck for Improved Generalizationcited by 1
- 2026Model See, Model Do? Exposure-Aware Evaluation of Bug-vs-Fix Preference in Code LLMscited by 1
- 2026GraphSteal: Structural Knowledge Stealing from Graph RAG via Traversal Reconstructioncited by 1
- 2024Memorization Capacity for Additive Fine-Tuning with Small ReLU Networkscited by 0
- 2025Memorization in Fine-Tuned Large Language Modelscited by 0
- 2025EL-MIA: Quantifying Membership Inference Risks of Sensitive Entities in LLMscited by 0
- 2026Extracting Training Dialogue Data from Large Language Model based Task Botscited by 0
- 2026Panoptic Pairwise Distortion Graphcited by 0
- 2026Reconstruction of Personally Identifiable Information from Proprietary Data in Supervised Fine-Tuned Modelscited by 0
- 2026Extracting Training Data from Diffusion Language Models via Infillingcited by 0
- 2026Not All 4-bit Quantizers Are Equal: Deployment-Time Mitigation of PII Leakage in Fine-Tuned Small Language Modelscited by 0
- 2026Not All 4-bit Quantizers Are Equal: Deployment-Time Mitigation of PII Leakage in Fine-Tuned Small Language Models2 Aug 2026
- 2026GraphSteal: Structural Knowledge Stealing from Graph RAG via Traversal Reconstruction27 May 2026
- 2026Extracting Training Data from Diffusion Language Models via Infilling22 May 2026
- 2026Reconstruction of Personally Identifiable Information from Proprietary Data in Supervised Fine-Tuned Models12 May 2026
- 2026Panoptic Pairwise Distortion Graph13 Apr 2026
- 2026Extracting Training Dialogue Data from Large Language Model based Task Bots2 Mar 2026
- 2026Benchmarking Knowledge-Extraction Attack and Defense on Retrieval-Augmented Generation10 Feb 2026
- 2026Membership Inference Attacks Against Fine-tuned Diffusion Language Models27 Jan 2026
- 2026Memorization Dynamics in Knowledge Distillation for Language Models21 Jan 2026
- 2026Model See, Model Do? Exposure-Aware Evaluation of Bug-vs-Fix Preference in Code LLMs15 Jan 2026
- 2026Window-based Membership Inference Attacks Against Fine-tuned Large Language Models6 Jan 2026
- 2025EL-MIA: Quantifying Membership Inference Risks of Sensitive Entities in LLMs31 Oct 2025
33 more
- 2025Breaking Memorization Barriers in LLM Code Fine-Tuning via Information Bottleneck for Improved Generalization15 Oct 2025
- 2025Detecting Data Contamination from Reinforcement Learning Post-training for Large Language Models10 Oct 2025
- 2025Exploring Cross-Client Memorization of Training Data in Large Language Models for Federated Learning9 Oct 2025
- 2025Direct Token Optimization: A Self-contained Approach to Large Language Model Unlearning30 Sep 2025
- 2025Memorization in Large Language Models in Medicine: Prevalence, Characteristics, and Implications10 Sep 2025
- 2025Memorization in Fine-Tuned Large Language Models28 Jul 2025
- 2025Tab-MIA: A Benchmark Dataset for Membership Inference Attacks on Tabular Data in LLMs23 Jul 2025
- 2025The Landscape of Memorization in LLMs: Mechanisms, Measurement, and Mitigation8 Jul 2025
- 2025Leaner Training, Lower Leakage: Revisiting Memorization in LLM Fine-Tuning with LoRA25 Jun 2025
- 2025Mirage of Mastery: Memorization Tricks LLMs into Artificially Inflated Self-Knowledge23 Jun 2025
- 2025LexiMark: Robust Watermarking via Lexical Substitutions to Enhance Membership Verification of an LLM's Textual Training Data17 Jun 2025
- 2025Too Big to Think: Capacity, Memorization, and Generalization in Pre-Trained Transformers10 Jun 2025
- 2025Privacy-Aware RAG: Secure and Isolated Knowledge Retrieval17 Mar 2025
- 2025Mitigating Memorization in LLMs using Activation Steering8 Mar 2025
- 2025Privacy Ripple Effects from Adding or Removing Personal Information in Language Model Training21 Feb 2025
- 2025Large Language Models Penetration in Scholarly Writing and Peer Review16 Feb 2025
- 2025Mitigating Unintended Memorization with LoRA in Federated Learning for LLMs7 Feb 2025
- 2025How Much Do Code Language Models Remember? An Investigation on Data Extraction Attacks before and after Fine-tuning29 Jan 2025
- 2024Efficient and Private: Memorisation under differentially private parameter-efficient fine-tuning in language models24 Nov 2024
- 2024On the Impact of Fine-Tuning on Chain-of-Thought Reasoning22 Nov 2024
- 2024Self-Comparison for Dataset-Level Membership Inference in Large (Vision-)Language Models16 Oct 2024
- 2024KBLaM: Knowledge Base augmented Language Model14 Oct 2024
- 2024Undesirable Memorization in Large Language Models: A Survey3 Oct 2024
- 2024Unlocking Memorization in Large Language Models with Dynamic Soft Prompting20 Sep 2024
- 2024Generalisation First, Memorisation Second? Memorisation Localisation for Natural Language Classification Tasks9 Aug 2024
- 2024Memorization Capacity for Additive Fine-Tuning with Small ReLU Networks1 Aug 2024
- 2024SoK: Membership Inference Attacks on LLMs are Rushing Nowhere (and How to Fix It)25 Jun 2024
- 2024Measuring memorization in RLHF for code completion17 Jun 2024
- 2024The Fault in our Stars: Quality Assessment of Code Generation Benchmarks15 Apr 2024
- 2024The Good and The Bad: Exploring Privacy Issues in Retrieval-Augmented Generation (RAG)23 Feb 2024
- 2024Retrieval Augmented Thought Process for Private Data Handling in Healthcare12 Feb 2024
- 2024Copyright Protection in Generative AI: A Technical Perspective4 Feb 2024
- 2023DPZero: Private Fine-Tuning of Language Models without Backpropagation14 Oct 2023
- 2024SoK: Membership Inference Attacks on LLMs are Rushing Nowhere (and How to Fix It)cited by 59
- 2025The Landscape of Memorization in LLMs: Mechanisms, Measurement, and Mitigationcited by 10
- 2026Window-based Membership Inference Attacks Against Fine-tuned Large Language Modelscited by 7
- 2025How Much Do Code Language Models Remember? An Investigation on Data Extraction Attacks before and after Fine-tuningcited by 3
- 2025Leaner Training, Lower Leakage: Revisiting Memorization in LLM Fine-Tuning with LoRAcited by 3
- 2025Tab-MIA: A Benchmark Dataset for Membership Inference Attacks on Tabular Data in LLMscited by 3
- 2025Direct Token Optimization: A Self-contained Approach to Large Language Model Unlearningcited by 2
- 2025LexiMark: Robust Watermarking via Lexical Substitutions to Enhance Membership Verification of an LLM's Textual Training Datacited by 1
- 2025EL-MIA: Quantifying Membership Inference Risks of Sensitive Entities in LLMscited by 0
- 2026Extracting Training Dialogue Data from Large Language Model based Task Botscited by 0
- 2026Extracting Training Dialogue Data from Large Language Model based Task Bots2 Mar 2026
- 2026Window-based Membership Inference Attacks Against Fine-tuned Large Language Models6 Jan 2026
- 2025EL-MIA: Quantifying Membership Inference Risks of Sensitive Entities in LLMs31 Oct 2025
- 2025Direct Token Optimization: A Self-contained Approach to Large Language Model Unlearning30 Sep 2025
- 2025Tab-MIA: A Benchmark Dataset for Membership Inference Attacks on Tabular Data in LLMs23 Jul 2025
- 2025The Landscape of Memorization in LLMs: Mechanisms, Measurement, and Mitigation8 Jul 2025
- 2025Leaner Training, Lower Leakage: Revisiting Memorization in LLM Fine-Tuning with LoRA25 Jun 2025
- 2025LexiMark: Robust Watermarking via Lexical Substitutions to Enhance Membership Verification of an LLM's Textual Training Data17 Jun 2025
- 2025How Much Do Code Language Models Remember? An Investigation on Data Extraction Attacks before and after Fine-tuning29 Jan 2025
- 2024SoK: Membership Inference Attacks on LLMs are Rushing Nowhere (and How to Fix It)25 Jun 2024
- 2024The Good and The Bad: Exploring Privacy Issues in Retrieval-Augmented Generation (RAG)cited by 159
- 2025Privacy-Aware RAG: Secure and Isolated Knowledge Retrievalcited by 10
- 2026Benchmarking Knowledge-Extraction Attack and Defense on Retrieval-Augmented Generationcited by 2
- 2026GraphSteal: Structural Knowledge Stealing from Graph RAG via Traversal Reconstructioncited by 1
- 2026GraphSteal: Structural Knowledge Stealing from Graph RAG via Traversal Reconstruction27 May 2026
- 2026Benchmarking Knowledge-Extraction Attack and Defense on Retrieval-Augmented Generation10 Feb 2026
- 2025Privacy-Aware RAG: Secure and Isolated Knowledge Retrieval17 Mar 2025
- 2024The Good and The Bad: Exploring Privacy Issues in Retrieval-Augmented Generation (RAG)23 Feb 2024
- 2024Measuring memorization in RLHF for code completioncited by 13
- 2024Measuring memorization in RLHF for code completion17 Jun 2024
- 2024Copyright Protection in Generative AI: A Technical Perspectivecited by 38
- 2024Undesirable Memorization in Large Language Models: A Surveycited by 29
- 2023DPZero: Private Fine-Tuning of Language Models without Backpropagationcited by 26
- 2024Unlocking Memorization in Large Language Models with Dynamic Soft Promptingcited by 21
- 2024KBLaM: Knowledge Base augmented Language Modelcited by 16
- 2025Privacy Ripple Effects from Adding or Removing Personal Information in Language Model Trainingcited by 10
- 2024The Fault in our Stars: Quality Assessment of Code Generation Benchmarkscited by 9
- 2024Generalisation First, Memorisation Second? Memorisation Localisation for Natural Language Classification Taskscited by 9
- 2025Mitigating Unintended Memorization with LoRA in Federated Learning for LLMscited by 7
- 2025Large Language Models Penetration in Scholarly Writing and Peer Reviewcited by 6
- 2025Detecting Data Contamination from Reinforcement Learning Post-training for Large Language Modelscited by 6
- 2025Memorization in Large Language Models in Medicine: Prevalence, Characteristics, and Implicationscited by 5
12 most cited of 22 All 22 (JSON)
- 2026Not All 4-bit Quantizers Are Equal: Deployment-Time Mitigation of PII Leakage in Fine-Tuned Small Language Models2 Aug 2026
- 2026Reconstruction of Personally Identifiable Information from Proprietary Data in Supervised Fine-Tuned Models12 May 2026
- 2026Panoptic Pairwise Distortion Graph13 Apr 2026
- 2026Model See, Model Do? Exposure-Aware Evaluation of Bug-vs-Fix Preference in Code LLMs15 Jan 2026
- 2025Breaking Memorization Barriers in LLM Code Fine-Tuning via Information Bottleneck for Improved Generalization15 Oct 2025
- 2025Detecting Data Contamination from Reinforcement Learning Post-training for Large Language Models10 Oct 2025
- 2025Exploring Cross-Client Memorization of Training Data in Large Language Models for Federated Learning9 Oct 2025
- 2025Memorization in Large Language Models in Medicine: Prevalence, Characteristics, and Implications10 Sep 2025
- 2025Memorization in Fine-Tuned Large Language Models28 Jul 2025
- 2025Mirage of Mastery: Memorization Tricks LLMs into Artificially Inflated Self-Knowledge23 Jun 2025
- 2025Privacy Ripple Effects from Adding or Removing Personal Information in Language Model Training21 Feb 2025
- 2025Large Language Models Penetration in Scholarly Writing and Peer Review16 Feb 2025
12 newest of 22 All 22 (JSON)