Understanding the Staged Dynamics of Transformers in Learning Latent Structure

Fuente: arXiv
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Main Authors: Saha, Rohan, Aminmansour, Farzane, Fyshe, Alona
Format: Preprint
Published: 2025
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author Saha, Rohan
Aminmansour, Farzane
Fyshe, Alona
author_facet Saha, Rohan
Aminmansour, Farzane
Fyshe, Alona
contents Language modeling has shown us that transformers can discover latent structure from context, but the dynamics of how they acquire different components of that structure remain poorly understood, leading to assertions that models just remix training data. In this work, we use the Alchemy benchmark in a controlled setting (Wang et al.,2021) to investigate latent structure learning. We train a small decoder-only transformer on three task variants: 1) inferring missing transitions from partial contextual information, 2) composing simple rules to solve multi-transition sequences, and 3) decomposing complex multi-step examples to infer intermediate transitions. By factorizing each task into interpretable components, we show that the model learns the different latent structure components in discrete stages. We also observe an asymmetry: the model composes fundamental transitions robustly, but struggles to decompose complex examples to discover the atomic transitions. Finally, using causal interventions, we identify layer-specific plasticity windows during which freezing substantially delays or prevents stage completion. These findings provide insight into how a transformer model acquires latent structure, offering a detailed view of how capabilities evolve during training.
format Preprint
id arxiv_https___arxiv_org_abs_2511_19328
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Understanding the Staged Dynamics of Transformers in Learning Latent Structure
Saha, Rohan
Aminmansour, Farzane
Fyshe, Alona
Machine Learning
Language modeling has shown us that transformers can discover latent structure from context, but the dynamics of how they acquire different components of that structure remain poorly understood, leading to assertions that models just remix training data. In this work, we use the Alchemy benchmark in a controlled setting (Wang et al.,2021) to investigate latent structure learning. We train a small decoder-only transformer on three task variants: 1) inferring missing transitions from partial contextual information, 2) composing simple rules to solve multi-transition sequences, and 3) decomposing complex multi-step examples to infer intermediate transitions. By factorizing each task into interpretable components, we show that the model learns the different latent structure components in discrete stages. We also observe an asymmetry: the model composes fundamental transitions robustly, but struggles to decompose complex examples to discover the atomic transitions. Finally, using causal interventions, we identify layer-specific plasticity windows during which freezing substantially delays or prevents stage completion. These findings provide insight into how a transformer model acquires latent structure, offering a detailed view of how capabilities evolve during training.
title Understanding the Staged Dynamics of Transformers in Learning Latent Structure
topic Machine Learning
url https://arxiv.org/abs/2511.19328