ReFT: Representation Finetuning for Language Models
Authors: name: Zhengxuan Wu; name: Aryaman Arora; name: Zheng Wang; name: Atticus Geiger; name: Dan Jurafsky; name: Christopher D. Manning; name: Christopher Potts
Published: 2024-04-04 17:00:37

Abstract: Parameter-efficient fine-tuning (PEFT) methods seek to adapt large models via
updates to a small number of weights. However, much prior interpretability work
has shown that representations encode rich semantic information, suggesting
that editing representations might be a more powerful alternative. Here, we
pursue this hypothesis by developing a family of Representation
Finetuning (ReFT) methods. ReFT methods operate on a frozen base model and
learn task-specific interventions on hidden representations. We define a strong
instance of the ReFT family, Low-rank Linear Subspace ReFT (LoReFT). LoReFT is
a drop-in replacement for existing PEFTs and learns interventions that are
10x-50x more parameter-efficient than prior state-of-the-art PEFTs. We showcase
LoReFT on eight commonsense reasoning tasks, four arithmetic reasoning tasks,
Alpaca-Eval v1.0, and GLUE. In all these evaluations, LoReFT delivers the best
balance of efficiency and performance, and almost always outperforms
state-of-the-art PEFTs. We release a generic ReFT training library publicly at
https://github.com/stanfordnlp/pyreft.