Which Attention Heads Matter for In-Context Learning?
Not on the map. Why?
Abstract (arXiv)
Large language models (LLMs) exhibit impressive in-context learning (ICL) capability, enabling them to perform new tasks using only a few demonstrations in the prompt. Two different mechanisms have been proposed to explain ICL: induction heads that find and copy relevant tokens, and function vector (FV) heads whose activations compute a latent encoding of the ICL task. To better understand which of the two distinct mechanisms drives ICL, we study and compare induction heads and FV heads in 12 language models. Through detailed ablations, we discover that few-shot ICL performance depends primarily on FV heads, especially in larger models. In addition, we uncover that FV and induction heads are connected: many FV heads start as induction heads during training before transitioning to the FV mechanism. This leads us to speculate that induction facilitates learning the more complex FV mechanism that ultimately drives ICL.
Key facts. Cited by 61 papers in the map (data through 14 Oct 2026). First posted on arXiv 19 Feb 2025.
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Citing papers per year: 2025: 34; 2026: 27.
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- 2025Emergent Abilities in Large Language Models: A Surveycited by 37
- 2025Emergent Symbolic Mechanisms Support Abstract Reasoning in Large Language Modelscited by 31
- 2025The Dual-Route Model of Inductioncited by 24
- 2025Strategy Coopetition Explains the Emergence and Transience of In-Context Learningcited by 17
- 2025May I have your Attention? Breaking Fine-Tuning based Prompt Injection Defenses using Architecture-Aware Attackscited by 15
- 2025Do different prompting methods yield a common task representation in language models?cited by 11
- 2025The Atlas of In-Context Learning: How Attention Heads Shape In-Context Retrieval Augmentationcited by 11
- 2025Repetitions are not all alike: distinct mechanisms sustain repetition in language modelscited by 10
- 2026What do Language Models Learn and When? The Implicit Curriculum Hypothesiscited by 10
- 2025Focus Directions Make Your Language Models Pay More Attention to Relevant Contextscited by 9
- 2025Mechanistic evaluation of Transformers and state space modelscited by 9
- 2025Just-in-time and distributed task representations in language modelscited by 9
38 more
- 2025Understanding In-context Learning of Addition via Activation Subspacescited by 8
- 2025Train Once, Reuse Everywhere: Generalizable Implicit In-Context Learning by Routing Attentioncited by 8
- 2025Thinking Sparks!: Emergent Attention Heads in Reasoning Models During Post Trainingcited by 8
- 2026Causality neq Invariance: Function and Concept Vectors in LLMscited by 8
- 2025Delta Attention: Fast and Accurate Sparse Attention Inference by Delta Correctioncited by 7
- 2025Predicting the Emergence of Induction Heads in Language Model Pretrainingcited by 7
- 2025Activation Reward Models for Few-Shot Model Alignmentcited by 6
- 2025Distinct Computations Emerge From Compositional Curricula in In-Context Learningcited by 5
- 2025Toward a Theory of Generalizability in LLM Mechanistic Interpretability Researchcited by 5
- 2025In-Context Algebracited by 5
- 2026ReAttn: Improving Attention-based Re-ranking via Attention Re-weightingcited by 5
- 2026Large Vision-Language Models Get Lost in Attentioncited by 5
- 2025Softmax ≥ Linear: Transformers may learn to classify in-context by kernel gradient descentcited by 4
- 2026Where Computation Lives Inside TabPFN: Causal Localisation of Attention Head Functioncited by 4
- 2025Illusion or Algorithm? Investigating Memorization, Emergence, and Symbolic Processing in In-Context Learningcited by 3
- 2025Latent Concept Disentanglement in Transformer-based Language Modelscited by 3
- 2025Task Vectors, Learned Not Extracted: Performance Gains and Mechanistic Insightcited by 3
- 2026Understanding Contextual Recall in Transformers: How Finetuning Enables In-Context Reasoning over Pretraining Knowledgecited by 3
- 2026Position: Don't Just "Fix it in Post": A Science of AI Must Study Training Dynamicscited by 3
- 2026Looking Is Not Picking: An Attention-Segment Account of Tool-Selection Failures in LLM Agentscited by 3
- 2025Function Induction and Task Generalization: An Interpretability Study with Off-by-One Additioncited by 2
- 2025DFAMS: Dynamic-flow guided Federated Alignment based Multi-prototype Searchcited by 2
- 2025Is In-Context Learning Learning?cited by 2
- 2025Induction Signatures Are Not Enough: A Matched-Compute Study of Load-Bearing Structure in In-Context Learningcited by 2
- 2025Localizing Task Recognition and Task Learning in In-Context Learning via Attention Head Analysiscited by 2
- 2026Compressed Sensing for Capability Localization in Large Language Modelscited by 2
- 2026HeadRank: Decoding-Free Passage Reranking via Preference-Aligned Attention Headscited by 2
- 2026Preference Heads in Large Language Models: A Mechanistic Framework for Interpretable Personalizationcited by 2
- 2026Function-Vector Heads Are Two Populations: Writers and Cancellers in In-Context Learningcited by 2
- 2026CompressKV: Semantic-Retrieval-Guided KV-Cache Compression for Resource-Efficient Long-Context LLM Inferencecited by 2
- 2025A circuit for predicting hierarchical structure in-context in Large Language Modelscited by 1
- 2026Explaining Attention with Program Synthesiscited by 1
- 2025Decomposing Prediction Mechanisms for In-Context Recallcited by 0
- 2025In-Context Learning Without Copyingcited by 0
- 2025The brain-AI convergence: Predictive and generative world models for general-purpose computationcited by 0
- 2025MIDUS: Memory-Infused Depth Up-Scalingcited by 0
- 2026Emergent Structured Representations Support Flexible In-Context Inference in Large Language Modelscited by 0
- 2026Temporal Dependencies in In-Context Learning: The Role of Induction Headscited by 0
50 most cited of 61 All 61 (JSON)
- 2026Generalization Dynamics of LM Pre-training27 Sep 2026
- 2026Identifiability and Order-Dimension Limits of In-Context Learning on Partial Orders14 Aug 2026
- 2026CompressKV: Semantic-Retrieval-Guided KV-Cache Compression for Resource-Efficient Long-Context LLM Inference23 Jun 2026
- 2026Explaining Attention with Program Synthesis17 Jun 2026
- 2026When Does Depth Matter For In-Context Learning? Adaptive Inference in Deep Transformers15 Jun 2026
- 2026Looking Is Not Picking: An Attention-Segment Account of Tool-Selection Failures in LLM Agents15 Jun 2026
- 2026Where Computation Lives Inside TabPFN: Causal Localisation of Attention Head Function11 Jun 2026
- 2026Necessary, Decodable and Reversible, Yet Not Transferable: A Stress Test for Attention-Head Role Claims6 Jun 2026
- 2026Position: Don't Just "Fix it in Post": A Science of AI Must Study Training Dynamics3 Jun 2026
- 2026Fast & Faithful Function Vectors3 Jun 2026
- 2026Function-Vector Heads Are Two Populations: Writers and Cancellers in In-Context Learning25 May 2026
- 2026Distributional Alignment as a Criterion for Designing Task Vectors in In-Context Learning20 May 2026
38 more
- 2026Do as I Say, Not as I Do: Instruction-Induction Conflict in LLMs19 May 2026
- 2026Large Vision-Language Models Get Lost in Attention7 May 2026
- 2026In-Context Examples Suppress Scientific Knowledge Recall in LLMs30 Apr 2026
- 2026Quantifying Aleatoric Uncertainty of In-Context Learning for Robust Measure of LLM Prediction Confidence28 Apr 2026
- 2026When Context Sticks: Studying Interference in In-Context Learning25 Apr 2026
- 2026Preference Heads in Large Language Models: A Mechanistic Framework for Interpretable Personalization24 Apr 2026
- 2026Exploring Language-Agnosticity in Function Vectors: A Case Study in Machine Translation21 Apr 2026
- 2026HeadRank: Decoding-Free Passage Reranking via Preference-Aligned Attention Heads19 Apr 2026
- 2026What do Language Models Learn and When? The Implicit Curriculum Hypothesis9 Apr 2026
- 2026Temporal Dependencies in In-Context Learning: The Role of Induction Heads1 Apr 2026
- 2026Understanding Contextual Recall in Transformers: How Finetuning Enables In-Context Reasoning over Pretraining Knowledge21 Mar 2026
- 2026Causality neq Invariance: Function and Concept Vectors in LLMs25 Feb 2026
- 2026ReAttn: Improving Attention-based Re-ranking via Attention Re-weighting23 Feb 2026
- 2026Compressed Sensing for Capability Localization in Large Language Models11 Feb 2026
- 2026Emergent Structured Representations Support Flexible In-Context Inference in Large Language Models8 Feb 2026
- 2025In-Context Algebra18 Dec 2025
- 2025MIDUS: Memory-Infused Depth Up-Scaling15 Dec 2025
- 2025The brain-AI convergence: Predictive and generative world models for general-purpose computation2 Dec 2025
- 2025Predicting the Emergence of Induction Heads in Language Model Pretraining21 Nov 2025
- 2025In-Context Learning Without Copying7 Nov 2025
- 2025Softmax ≥ Linear: Transformers may learn to classify in-context by kernel gradient descent12 Oct 2025
- 2025Thinking Sparks!: Emergent Attention Heads in Reasoning Models During Post Training30 Sep 2025
- 2025Task Vectors, Learned Not Extracted: Performance Gains and Mechanistic Insight29 Sep 2025
- 2025Localizing Task Recognition and Task Learning in In-Context Learning via Attention Head Analysis29 Sep 2025
- 2025Induction Signatures Are Not Enough: A Matched-Compute Study of Load-Bearing Structure in In-Context Learning26 Sep 2025
- 2025Train Once, Reuse Everywhere: Generalizable Implicit In-Context Learning by Routing Attention26 Sep 2025
- 2025Toward a Theory of Generalizability in LLM Mechanistic Interpretability Research26 Sep 2025
- 2025A circuit for predicting hierarchical structure in-context in Large Language Models25 Sep 2025
- 2025Is In-Context Learning Learning?12 Sep 2025
- 2025Just-in-time and distributed task representations in language models28 Aug 2025
- 2025DFAMS: Dynamic-flow guided Federated Alignment based Multi-prototype Search28 Aug 2025
- 2025Function Induction and Task Generalization: An Interpretability Study with Off-by-One Addition14 Jul 2025
- 2025May I have your Attention? Breaking Fine-Tuning based Prompt Injection Defenses using Architecture-Aware Attacks10 Jul 2025
- 2025Decomposing Prediction Mechanisms for In-Context Recall2 Jul 2025
- 2025Activation Reward Models for Few-Shot Model Alignment2 Jul 2025
- 2025Latent Concept Disentanglement in Transformer-based Language Models20 Jun 2025
- 2025Distinct Computations Emerge From Compositional Curricula in In-Context Learning16 Jun 2025
- 2025The Atlas of In-Context Learning: How Attention Heads Shape In-Context Retrieval Augmentation21 May 2025
50 newest of 61 All 61 (JSON)
- 2025Emergent Symbolic Mechanisms Support Abstract Reasoning in Large Language Modelscited by 31
- 2025Thinking Sparks!: Emergent Attention Heads in Reasoning Models During Post Trainingcited by 8
- 2026Understanding Contextual Recall in Transformers: How Finetuning Enables In-Context Reasoning over Pretraining Knowledgecited by 3
- 2026Compressed Sensing for Capability Localization in Large Language Modelscited by 2
- 2026In-Context Examples Suppress Scientific Knowledge Recall in LLMscited by 0
- 2026In-Context Examples Suppress Scientific Knowledge Recall in LLMs30 Apr 2026
- 2026Understanding Contextual Recall in Transformers: How Finetuning Enables In-Context Reasoning over Pretraining Knowledge21 Mar 2026
- 2026Compressed Sensing for Capability Localization in Large Language Models11 Feb 2026
- 2025Thinking Sparks!: Emergent Attention Heads in Reasoning Models During Post Training30 Sep 2025
- 2025Emergent Symbolic Mechanisms Support Abstract Reasoning in Large Language Models27 Feb 2025
- 2025Activation Reward Models for Few-Shot Model Alignmentcited by 6
- 2026Large Vision-Language Models Get Lost in Attentioncited by 5
- 2026Large Vision-Language Models Get Lost in Attention7 May 2026
- 2025Activation Reward Models for Few-Shot Model Alignment2 Jul 2025
- 2025Emergent Abilities in Large Language Models: A Surveycited by 37
- 2025The Dual-Route Model of Inductioncited by 24
- 2025Strategy Coopetition Explains the Emergence and Transience of In-Context Learningcited by 17
- 2025Do different prompting methods yield a common task representation in language models?cited by 11
- 2025The Atlas of In-Context Learning: How Attention Heads Shape In-Context Retrieval Augmentationcited by 11
- 2025Repetitions are not all alike: distinct mechanisms sustain repetition in language modelscited by 10
- 2026What do Language Models Learn and When? The Implicit Curriculum Hypothesiscited by 10
- 2025Focus Directions Make Your Language Models Pay More Attention to Relevant Contextscited by 9
- 2025Just-in-time and distributed task representations in language modelscited by 9
- 2025Understanding In-context Learning of Addition via Activation Subspacescited by 8
- 2025Train Once, Reuse Everywhere: Generalizable Implicit In-Context Learning by Routing Attentioncited by 8
- 2026Causality neq Invariance: Function and Concept Vectors in LLMscited by 8
12 most cited of 46 All 46 (JSON)
- 2026Generalization Dynamics of LM Pre-training27 Sep 2026
- 2026Identifiability and Order-Dimension Limits of In-Context Learning on Partial Orders14 Aug 2026
- 2026Explaining Attention with Program Synthesis17 Jun 2026
- 2026When Does Depth Matter For In-Context Learning? Adaptive Inference in Deep Transformers15 Jun 2026
- 2026Necessary, Decodable and Reversible, Yet Not Transferable: A Stress Test for Attention-Head Role Claims6 Jun 2026
- 2026Position: Don't Just "Fix it in Post": A Science of AI Must Study Training Dynamics3 Jun 2026
- 2026Fast & Faithful Function Vectors3 Jun 2026
- 2026Function-Vector Heads Are Two Populations: Writers and Cancellers in In-Context Learning25 May 2026
- 2026Distributional Alignment as a Criterion for Designing Task Vectors in In-Context Learning20 May 2026
- 2026Do as I Say, Not as I Do: Instruction-Induction Conflict in LLMs19 May 2026
- 2026Quantifying Aleatoric Uncertainty of In-Context Learning for Robust Measure of LLM Prediction Confidence28 Apr 2026
- 2026When Context Sticks: Studying Interference in In-Context Learning25 Apr 2026
12 newest of 46 All 46 (JSON)