arXiv Computation and Language

In-Context Learning Beyond Copying: A Training-Time Analysis of Abstractive ICL

The paper investigates the relationship between in-context copying and the emergence of abstractive in-context learning (ICL) in large language models. By introducing Hapax, a training regime that removes loss contributions from tokens predictable by induction circuits, the authors show that abstractive ICL can still develop even when copying signals are largely suppressed. Attention analysis reveals that Hapax-trained models exhibit fewer and weaker induction heads, indicating a weaker developmental link between induction circuits and abstractive ICL than previously thought.

arXiv Machine Learning
Oct 23

How Depth Growth and Looping Shape In-Context Learning in Language Models

The paper investigates how depth growth and looping in language models influence in-context learning (ICL). It shows that models with these architectural features rely more on contextual information, acquire ICL earlier, and retain it better than fully dense counterparts. Attention analysis reveals that depth growth propagates early induction heads across layers, and ablations confirm that these models depend more on induction-ranked heads for few‑shot performance and token prediction.

By Ferdinand Kapl, Kaitlin Maile, Stefan Bauer, Johannes von Oswald
arXiv Machine Learning
Oct 15

From Copying to Composition: How Language Models Develop In-Context Learning

The study investigates how language models acquire in-context learning (ICL) by distinguishing between copying a nearby demonstration and integrating information across a prompt. Across 17 models, roughly one-third default to copied answers, a few are undecided, and the remainder favor rule-consistent answers that yield higher accuracy and are guided by the requested value rather than the nearest conflicting example. Analyses show that models prioritize task-relevant prompt tokens before accuracy surpasses chance, and that synthetic or fine-tuned training can shift models toward compositional responses or improve accuracy when prompts reassign label meanings.

By Minglai Yang, Xinyu Guo, Renxiong Wang, Sunjie Hou, Daniel Yue Zhang, Yunzhong He
arXiv Machine Learning
Oct 19

Out of Support, Not Out of Reach: In-Context Learning with Unsupported Instructions and Composed Tasks

The paper investigates when in‑context learning (ICL) can succeed even if the instruction or target task is not covered by a model’s pretraining data. It introduces a theoretical framework that distinguishes two types of distribution shift—unsupported instructions and unsupported target tasks—and shows how demonstrations can mitigate these shifts. The authors further extend the analysis to long‑horizon tasks that can be decomposed into pretraining‑supported subtasks, providing error bounds that explain how ICL can handle tasks beyond the model’s original support.

By Xuhan Tong, Yuchen Zeng, Jiawei Zhang
arXiv AI
Sep 15

Convergent Emergence of In-Context Learning Across Modalities

The paper investigates whether few-shot in-context learning (ICL) emerges similarly across different data modalities. Using a controlled cross-modality framework, the authors test the Convergent Emergence Hypothesis, which posits that tasks benefiting from ICL in one modality will also benefit in others. They find that paired-mapping ICL appears in six modalities—language, genome, integer sequences, time series, images, and proteins—outperforming baselines and showing correlated task effects in five of them, supporting the hypothesis in some but not all cases.

By Nathan Breslow, Seungwook Han, Daniel Hyunsoo Lee, Aayush Mishra, Anqi Liu, Daniel Khashabi
arXiv AI
Sep 1

Mechanism Shift During Post-training from Autoregressive to Masked Diffusion Language Models

The study investigates how post‑training of large autoregressive language models (ARMs) into masked diffusion models (MDMs) affects their internal computation. Across two 7B ARM‑MDM families and four diagnostic tasks, the authors find that MDMs retain much of the ARM’s high‑attribution pathways on prefix‑dominant tasks, but reorganize computation toward earlier layers on globally constrained tasks. Component‑level probes reveal that ARMs depend on sharply specialized components, whereas MDMs show weaker specialization and more diffuse output‑space alignment.

By Injin Kong, Hyoungjoon Lee, Yohan Jo
arXiv Machine Learning
Oct 3

Localizing Transfer Between Memorization Tasks

The paper investigates how pre‑training on random input‑output mappings (memorization tasks) can transfer to downstream tasks. It discovers two unexpected patterns: equivalent transfer, where each pre‑training epoch saves roughly one fine‑tuning epoch, and non‑equivalent transfer, where pre‑training on a mismatched task can be more efficient than training directly on the downstream task. Ablation studies reveal that transfer consists of a trivial magnitude‑driven effect in the last layer and a non‑trivial structure‑driven effect linked to covariance in other layers.

By Yimiao Yu, Florentin Guth