arXiv Computation and Language

The Emergence and Sparsification of a Syntactic Circuit

arXiv Computation and Language
Oct 21

Are Linguistic and Arithmetic Circuits Dissociated in LLMs?

The paper investigates whether linguistic and arithmetic tasks in large language models (LLMs) rely on shared neural circuits. Using mechanistic interpretability techniques on five LLMs, the authors find that circuit similarity aligns primarily with task domain rather than input/output vocabularies or syntactic structure. This suggests that LLMs may employ largely separate neural circuits for language and arithmetic, indicating a modular organization of abilities.

By Riku Kisako, Tatsuki Kuribayashi, Ryohei Sasano
arXiv AI
Oct 16

Learning to Read Out: Unembedding Dynamics in Language Model Pretraining

The paper investigates when a language model actually learns task information versus when its readout (unembedding matrix) learns to express that information. Using a new parameter‑trajectory cross‑coding method, the authors find that hidden states can encode task data early in training, but the readout reorganizes only in a narrow window (0.4–1.1% of Pythia’s pretraining). By varying the readout learning rate, they show that faster readout learning reduces the gap between hidden‑state encoding and output expression without affecting final performance.

By Matteo He, William F. Shen, Alex Iacob, Andrej Jovanovic, Xinchi Qiu, Nicholas D. Lane
arXiv Computation and Language
Oct 23

Verbalizing Activation Differences with Natural Language Autoencoders

The paper investigates natural language autoencoders (NLAs) as tools for verbalizing activation differences in large language models. It examines whether NLAs capture compositional structure, generalize to fine‑tuned models, recover fine‑tuning objectives, and can be specialized for model diffing. Experiments across four models show that NLAs largely succeed in these tasks, though they do not yet match state‑of‑the‑art diffing methods on emergent misalignment detection.

By Andrea Blasi N\'u\~nez, Gianluca Barmina, Federico Torrielli, Thiusius Rajeeth Savarimuthu, Peter Schneider-Kamp, Lukas Galke Poech
arXiv Computation and Language
Oct 15

Do Syntax Heads Influence Model Behavior?

The paper investigates whether attention heads in transformer language models that specialize in syntactic relations causally influence the models’ syntactic predictions. Experiments show mixed to negative evidence: even when these heads are forced to attend to a distractor noun, the model’s predictions still favor the correct subject. Interventions on syntax-specialized heads affect predictions more than random heads, but only for one of two proposed measures.

By William Timkey, Tal Linzen
Hugging Face Trending Papers
Oct 22

Verbalizing Activation Differences with Natural Language Autoencoders

The paper investigates natural language autoencoders (NLAs) that convert large language model activations into readable text. It examines whether NLAs capture compositional structure, generalize to fine‑tuned models, recover fine‑tuning objectives, and can be specialized for model diffing. Experiments across multiple models show positive results: NLAs preserve compositionality, transfer to lightweight fine‑tunes, recover hidden objectives, and outperform a black‑box baseline on diffing tasks, though they lag behind state‑of‑the‑art methods for misalignment detection.