arXiv Computation and Language

SYNC: A Training-Free Inference Controller for Dynamic Layer Selection in Multi-Persona Alignment

The paper introduces SYNC, a training‑free inference controller that dynamically selects the optimal layer for injecting persona steering vectors during decoding. SYNC estimates each layer’s sensitivity to every persona using cosine similarity trajectories, allowing the model to adaptively choose the best injection point at each step. Experiments on two models and multiple persona profiles show that SYNC outperforms static multi‑persona steering methods in 21 of 28 configurations, with significant gains in 15 cases.

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
Oct 16

Where to Steer: Input-Dependent Layer Selection for Steering Improves LLM Alignment

The paper introduces Where to Steer (W2S), a framework that adaptively selects which layer of a large language model to intervene on based on the input. It argues that optimal steering layers vary across inputs and demonstrates that W2S outperforms fixed-layer steering methods on several LLMs and alignment tasks, both in‑distribution and out‑of‑distribution. The study highlights input‑dependent layer selection as a complementary design dimension to steering vector extraction.

By Soham Gadgil, Chris Lin, Su-In Lee
arXiv Machine Learning
Oct 8

Learning Cross-Model Activation Alignments with Explicit Many-to-Many Layer Maps

The paper introduces MATCHA, a method that learns explicit many-to-many layer maps between independently trained language models. MATCHA decomposes the alignment into a layer map—an explicit target‑by‑source matrix—and a shared feature map, allowing joint learning of layer correspondence and feature transformation from prompts. Experiments on 42 model pairs across three families show that MATCHA reconstructs target activations more faithfully and improves retrieval metrics, while enabling transfer of activation‑space interventions between models.

By Alina Sudakov, Guy Bar-Shalom, Fabrizio Frasca, Haggai Maron