Extrapolation by Association: Length Generalization Transfer in Transformers

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Hauptverfasser: Cai, Ziyang, Lee, Nayoung, Schwarzschild, Avi, Oymak, Samet, Papailiopoulos, Dimitris
Format: Preprint
Veröffentlicht: 2025
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author Cai, Ziyang
Lee, Nayoung
Schwarzschild, Avi
Oymak, Samet
Papailiopoulos, Dimitris
author_facet Cai, Ziyang
Lee, Nayoung
Schwarzschild, Avi
Oymak, Samet
Papailiopoulos, Dimitris
contents Transformer language models have demonstrated impressive generalization capabilities in natural language domains, yet we lack a fine-grained understanding of how such generalization arises. In this paper, we investigate length generalization--the ability to extrapolate from shorter to longer inputs--through the lens of \textit{task association}. We find that length generalization can be \textit{transferred} across related tasks. That is, training a model with a longer and related auxiliary task can lead it to generalize to unseen and longer inputs from some other target task. We demonstrate this length generalization transfer across diverse algorithmic tasks, including arithmetic operations, string transformations, and maze navigation. Our results show that transformer models can inherit generalization capabilities from similar tasks when trained jointly. Moreover, we observe similar transfer effects in pretrained language models, suggesting that pretraining equips models with reusable computational scaffolding that facilitates extrapolation in downstream settings. Finally, we provide initial mechanistic evidence that length generalization transfer correlates with the re-use of the same attention heads between the tasks. Together, our findings deepen our understanding of how transformers generalize to out-of-distribution inputs and highlight the compositional reuse of inductive structure across tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2506_09251
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Extrapolation by Association: Length Generalization Transfer in Transformers
Cai, Ziyang
Lee, Nayoung
Schwarzschild, Avi
Oymak, Samet
Papailiopoulos, Dimitris
Computation and Language
Artificial Intelligence
Transformer language models have demonstrated impressive generalization capabilities in natural language domains, yet we lack a fine-grained understanding of how such generalization arises. In this paper, we investigate length generalization--the ability to extrapolate from shorter to longer inputs--through the lens of \textit{task association}. We find that length generalization can be \textit{transferred} across related tasks. That is, training a model with a longer and related auxiliary task can lead it to generalize to unseen and longer inputs from some other target task. We demonstrate this length generalization transfer across diverse algorithmic tasks, including arithmetic operations, string transformations, and maze navigation. Our results show that transformer models can inherit generalization capabilities from similar tasks when trained jointly. Moreover, we observe similar transfer effects in pretrained language models, suggesting that pretraining equips models with reusable computational scaffolding that facilitates extrapolation in downstream settings. Finally, we provide initial mechanistic evidence that length generalization transfer correlates with the re-use of the same attention heads between the tasks. Together, our findings deepen our understanding of how transformers generalize to out-of-distribution inputs and highlight the compositional reuse of inductive structure across tasks.
title Extrapolation by Association: Length Generalization Transfer in Transformers
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2506.09251