Portrait of Tianwei Ni

Tianwei Ni

PhD - Université de Montréal
Supervisor
Pierre-Luc Bacon
Research Topics
Large Language Models (LLM)
Reasoning
Reinforcement Learning
Representation Learning
Website
Google Scholar
GitHub

Publications

When Do Transformers Shine in RL? Decoupling Memory from Credit Assignment
Tianwei Ni
Michel Ma
Benjamin Eysenbach
Pierre-Luc Bacon
Reinforcement learning (RL) algorithms face two distinct challenges: learning effective representations of past and present observations, an… (see more)d determining how actions influence future returns. Both challenges involve modeling long-term dependencies. The Transformer architecture has been very successful to solve problems that involve long-term dependencies, including in the RL domain. However, the underlying reason for the strong performance of Transformer-based RL methods remains unclear: is it because they learn effective memory, or because they perform effective credit assignment? After introducing formal definitions of memory length and credit assignment length, we design simple configurable tasks to measure these distinct quantities. Our empirical results reveal that Transformers can enhance the memory capability of RL algorithms, scaling up to tasks that require memorizing observations
openreview.net