arXiv Computation and Language

K/V-Cache Interventions Dissociate Representation Alignment from Persona Expression in Decoder-Only Language Models

The paper investigates K/V-cache interventions—transplanting a target-conditioned key/value trajectory into a source-persona generation—as a method for controlling persona in decoder-only language models. Experiments on Llama‑3.1‑8B across 13 configurations reveal that strong representation alignment (measured by V‑gap) does not guarantee behavioral persona expression, with only mid‑layer replacements achieving both alignment and lexical diversity. Position perturbations uniformly suppress persona expression, highlighting that representation similarity alone is insufficient to predict downstream behavior.

arXiv AI
Aug 14

Synthetic Persona Pretraining: Alignment from Token Zero

arXiv:2608. 13482v1 Announce Type: cross Abstract: As language-model-based AI is increasingly deployed in autonomous settings, aligning its goals and values with those of humans becomes critical.

By Julian Minder, Viktor Moskvoretskii, Raghav Singhal, Difan Jiao, Andy Arditi, Shaobo Cui, Yiderigun Borjigin, Kartik Bali, Stefan Krsteski, Harsh Raj, Huu Nguyen, Jannik Brinkmann, Ashton Anderson, Roland Aydin, Robert West
arXiv Machine Learning
Jun 2

Measuring Alignment-Induced Activation Shifts Correctly: A Template-Controlled Difference-in-Differences Protocol

arXiv:2605. 24583v3 Announce Type: replace Abstract: Comparing a model's internal activations before and after alignment is a natural way to ask what safety training changes: one forms the matrix of paired aligned-minus-base activations on safety-relevant inputs and reads off its effective rank or top direction.

By Yuki Nakamura
arXiv Machine Learning
1d ago

Persistent Depth Ordering amid Shifting Block-Bypass Responses in Language Model Pretraining

The study investigates how layer‑wise intervention responses in language models change over the course of pretraining, using single‑block identity bypass across multiple checkpoints and model‑domain combinations. It finds that while depth ordering of responses persists, their magnitudes shift, with nearby checkpoints showing stronger rank correspondence than distant ones and large changes occurring at positions that recur across samples and transfer across evaluation domains. Controlled experiments reveal that these longitudinal changes cannot be explained by a single downstream sensitivity and depend on perturbation strength and direction, indicating that layer sensitivity is structured but dynamic.

By Shengye Tao, Yinzhu Cheng, Haihua Xie