arXiv AI

Contrastive Covariance Subspaces for Activation Steering

arXiv AI
Sep 3

Task-Level Natural Language Priors as Learning Signals for Low-Resource LLM Training

Task-Level Natural Language Priors as Learning Signals for Low-Resource LLM Training proposes Prior-Guided Tuning (PGT), a training approach that treats natural-language priors as auxiliary learning signals rather than just input context. The method introduces Contrastive Prior Steering (CPS), which adds positive and negative prior-conditioned auxiliary losses while preserving the original supervised objective. Experiments on AmbiMath, Jigsaw, and MNLI/HANS demonstrate that CPS consistently outperforms plain and prompt fine-tuning, achieving high accuracy and significant gains with limited training data.

By Jian Gao, Xiao Zhang, Xun Zhu, Miao Li, Ji Wu
arXiv Machine Learning
Oct 15

Genesis Steering: Better Activation Steering Through Training Data

The paper introduces genesis steering, a method that derives a steering vector from contrastive examples in a model’s own fine‑tuning data, and proposes using membership inference to build proxy datasets when such data are unavailable. Two theoretical results are presented on optimal displacement to the decision boundary and reduced proxy‑estimation bias. Experiments on T"ulu‑3‑8B and Llama‑3.1‑8B‑Instruct show that safety data from T"ulu‑3‑8B’s training mixture produce stronger steering than external datasets, and that membership‑based proxy construction can achieve competitive performance.

By Tora Bodin, Eric Aubinais, Ilaria Torre, Chih-Hong Cheng
arXiv Machine Learning
Sep 3

IDEEA: training-free Input-Dependent stEEring via Activation cluster matching

IDEA is a training‑free, input‑dependent steering method for large language models that matches activations to cluster‑specific directions aligned with a target concept. It clusters positive and negative activation supports per attention head, solves an optimal‑matching problem to create a pool of cluster‑conditional directions, and selects the best match for each input at inference time. This approach preserves the input’s original representation while improving the truth × info rate on TruthfulQA by an average of 9.9% (up to 23.5%) over input‑independent baselines.

By Zheng Wang, Muchen Li, Renjie Liao, Yan Leng