Context Structure Reshapes the Representational Geometry of Language Models

Fuente: arXiv
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Auteurs principaux: Hosseini, Eghbal A., Li, Yuxuan, Bahri, Yasaman, Campbell, Declan, Lampinen, Andrew Kyle
Format: Preprint
Publié: 2026
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author Hosseini, Eghbal A.
Li, Yuxuan
Bahri, Yasaman
Campbell, Declan
Lampinen, Andrew Kyle
author_facet Hosseini, Eghbal A.
Li, Yuxuan
Bahri, Yasaman
Campbell, Declan
Lampinen, Andrew Kyle
contents Large Language Models (LLMs) have been shown to organize the representations of input sequences into straighter neural trajectories in their deep layers, which has been hypothesized to facilitate next-token prediction via linear extrapolation. Language models can also adapt to diverse tasks and learn new structure in context, and recent work has shown that this in-context learning (ICL) can be reflected in representational changes. Here we bring these two lines of research together to explore whether representation straightening occurs \emph{within} a context during ICL. We measure representational straightening in Gemma 2 models across a diverse set of in-context tasks, and uncover a dichotomy in how LLMs' representations change in context. In continual prediction settings (e.g., natural language, grid world traversal tasks) we observe that increasing context increases the straightness of neural sequence trajectories, which is correlated with improvement in model prediction. Conversely, in structured prediction settings (e.g., few-shot tasks), straightening is inconsistent -- it is only present in phases of the task with explicit structure (e.g., repeating a template), but vanishes elsewhere. These results suggest that ICL is not a monolithic process. Instead, we propose that LLMs function like a Swiss Army knife: depending on task structure, the LLM dynamically selects between strategies, only some of which yield representational straightening.
format Preprint
id arxiv_https___arxiv_org_abs_2601_22364
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Context Structure Reshapes the Representational Geometry of Language Models
Hosseini, Eghbal A.
Li, Yuxuan
Bahri, Yasaman
Campbell, Declan
Lampinen, Andrew Kyle
Computation and Language
Artificial Intelligence
Large Language Models (LLMs) have been shown to organize the representations of input sequences into straighter neural trajectories in their deep layers, which has been hypothesized to facilitate next-token prediction via linear extrapolation. Language models can also adapt to diverse tasks and learn new structure in context, and recent work has shown that this in-context learning (ICL) can be reflected in representational changes. Here we bring these two lines of research together to explore whether representation straightening occurs \emph{within} a context during ICL. We measure representational straightening in Gemma 2 models across a diverse set of in-context tasks, and uncover a dichotomy in how LLMs' representations change in context. In continual prediction settings (e.g., natural language, grid world traversal tasks) we observe that increasing context increases the straightness of neural sequence trajectories, which is correlated with improvement in model prediction. Conversely, in structured prediction settings (e.g., few-shot tasks), straightening is inconsistent -- it is only present in phases of the task with explicit structure (e.g., repeating a template), but vanishes elsewhere. These results suggest that ICL is not a monolithic process. Instead, we propose that LLMs function like a Swiss Army knife: depending on task structure, the LLM dynamically selects between strategies, only some of which yield representational straightening.
title Context Structure Reshapes the Representational Geometry of Language Models
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2601.22364