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Richard Lewis

9 accepted papers

2026

Bound by semanticity: universal laws governing the generalization-identification tradeoff

ICLR 2026poster

Intelligent systems must form internal representations that support both broad generalization and precise identification. Here, we show that these two goals are fundamentally in tension with one another. We derive closed-form expressions proving that any model whose representations have a finite s…

Cited by 0SourceScholar
2025

Do Language Models Understand the Cognitive Tasks Given to Them? Investigations with the N-Back Paradigm

ACL 2025finding

Cognitive tasks originally developed for humans are now increasingly used to study language models. While applying these tasks is often straightforward, interpreting their results can be challenging. In particular, when a model underperforms, it is often unclear whether this results from a limitatio…

Cited by 0SourcePDFScholar
2023

Combining Behaviors with the Successor Features Keyboard

NeurIPS 2023poster

The Option Keyboard (OK) was recently proposed as a method for transferring behavioral knowledge across tasks. OK transfers knowledge by adaptively combining subsets of known behaviors using Successor Features (SFs) and Generalized Policy Improvement (GPI). However, it relies on hand-designed state-…

Cited by 7SourcePDFScholar
2023

Composing Task Knowledge With Modular Successor Feature Approximators

ICLR 2023poster

Recently, the Successor Features and Generalized Policy Improvement (SF&GPI) framework has been proposed as a method for learning, composing and transferring predictive knowledge and behavior. SF&GPI works by having an agent learn predictive representations (SFs) that can be combined for transfer to…

Cited by 12SourcePDFScholar
2023

In-Context Analogical Reasoning with Pre-Trained Language Models

ACL 2023long

Analogical reasoning is a fundamental capacity of human cognition that allows us to reason abstractly about novel situations by relating them to past experiences. While it is thought to be essential for robust reasoning in AI systems, conventional approaches require significant training and/or hard-…

2023

Large Language Models can Implement Policy Iteration

NeurIPS 2023poster

In this work, we demonstrate a method for implementing policy iteration using a large language model. While the application of foundation models to RL has received considerable attention, most approaches rely on either (1) the curation of expert demonstrations (either through manual design or task-s…

Cited by 18SourcePDFScholar
2022

Adaptive Pairwise Weights for Temporal Credit Assignment

AAAI 2022technical

How much credit (or blame) should an action taken in a state get for a future reward? This is the fundamental temporal credit assignment problem in Reinforcement Learning (RL). One of the earliest and still most widely used heuristics is to assign this credit based on a scalar coefficient, lambda (t…

Cited by 5SourcePDFScholar
2021

Learning State Representations from Random Deep Action-conditional Predictions

NeurIPS 2021poster

Our main contribution in this work is an empirical finding that random General Value Functions (GVFs), i.e., deep action-conditional predictions---random both in what feature of observations they predict as well as in the sequence of actions the predictions are conditioned upon---form good auxiliary…

2021

Reinforcement Learning for Sparse-Reward Object-Interaction Tasks in a First-person Simulated 3D Environment

IJCAI 2021poster

Learning how to execute complex tasks involving multiple objects in a 3D world is challenging when there is no ground-truth information about the objects or any demonstration to learn from. When an agent only receives a signal from task-completion, this makes it challenging to learn the object-repr…

Cited by 12SourcePDFScholar