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Ethan Perez

24 accepted papers

2026

Bits That Count: Quantifying and Predicting Capabilities of Language Models

ICML 2026poster

What and how do language models learn during training? When does learning elicit \textit{existing} knowledge, and when does it primarily teach \textit{new} capabilities? We find that the amount of generalizable information language models learn during training predicts the origins of their emergent …

Cited by 0SourceScholar
2026

Constitutional Classifiers++: Production-Grade Defenses against Universal Jailbreaks

ICLR 2026poster

We introduce enhanced Constitutional Classifiers that deliver production-grade jailbreak robustness with dramatically reduced computational costs and refusal rates compared to previous-generation defenses. We first identify vulnerabilities in existing systems that evaluate model outputs without rega…

Cited by 0SourceScholar
2026

The Hot Mess of AI: How Does Misalignment Scale With Model Intelligence and Task Complexity?

ICLR 2026poster

As AI becomes more capable, we entrust it with more general and consequential tasks. The risks from failure grow more severe with increasing task scope. It is therefore important to understand the ways extremely capable AI models will fail: Will they fail by systematically pursuing goals we do not…

Cited by 0SourcecodeScholar
2025

Adaptive Deployment of Untrusted LLMs Reduces Distributed Threats

ICLR 2025poster

As large language models (LLMs) grow more powerful, they also become more difficult to trust. They could be either aligned with human intentions, or exhibit "subversive misalignment" -- introducing subtle errors that bypass safety checks. Although individual errors may not immediately cause harm, ea…

Cited by 3SourcePDFScholar
2025

Failures to Find Transferable Image Jailbreaks Between Vision-Language Models

ICLR 2025poster

The integration of new modalities into frontier AI systems offers exciting capabilities, but also increases the possibility such systems can be adversarially manipulated in undesirable ways. In this work, we focus on a popular class of vision-language models (VLMs) that generate text outputs conditi…

Cited by 3SourcePDFScholar
2025

Language Models Learn to Mislead Humans via RLHF

ICLR 2025poster

Language models (LMs) can produce errors that are hard to detect for humans, especially when the task is complex. RLHF, the most popular post-training method, may exacerbate this problem: to achieve higher rewards, LMs might get better at convincing humans that they are right even when they are wron…

2025

Looking Inward: Language Models Can Learn About Themselves by Introspection

ICLR 2025poster

Humans acquire knowledge by observing the external world, but also by introspection. Introspection gives a person privileged access to their current state of mind (e.g. thoughts and feelings) that are not accessible to external observers. Do LLMs have this introspective capability of privileged acce…

2025

Quantifying Elicitation of Latent Capabilities in Language Models

NeurIPS 2025poster

Large language models often possess latent capabilities that lie dormant unless explicitly elicited, or surfaced, through fine-tuning or prompt engineering. Predicting, assessing, and understanding these latent capabilities pose significant challenges in the development of effective, safe AI systems…

Cited by 0SourceScholar
2024

Debating with More Persuasive LLMs Leads to More Truthful Answers

ICML 2024oral

Common methods for aligning large language models (LLMs) with desired behaviour heavily rely on human-labelled data. However, as models grow increasingly sophisticated, they will surpass human expertise, and the role of human evaluation will evolve into non-experts overseeing experts. In anticipatio…

2024

Towards Understanding Sycophancy in Language Models

ICLR 2024poster

Reinforcement learning from human feedback (RLHF) is a popular technique for training high-quality AI assistants. However, RLHF may also encourage model responses that match user beliefs over truthful responses, a behavior known as sycophancy. We investigate the prevalence of sycophancy in RLHF-trai…

2024

Vision-Language Models are Zero-Shot Reward Models for Reinforcement Learning

ICLR 2024poster

Reinforcement learning (RL) requires either manually specifying a reward function, which is often infeasible, or learning a reward model from a large amount of human feedback, which is often very expensive. We study a more sample-efficient alternative: using pretrained vision-language models (VLMs)…

2023

Discovering Language Model Behaviors with Model-Written Evaluations

ACL 2023findings

As language models (LMs) scale, they develop many novel behaviors, good and bad, exacerbating the need to evaluate how they behave. Prior work creates evaluations with crowdwork (which is time-consuming and expensive) or existing data sources (which are not always available). Here, we automatically…

2023

Few-shot Adaptation Works with UnpredicTable Data

ACL 2023long

Prior work on language models (LMs) shows that training on a large number of diverse tasks improves few-shot learning (FSL) performance on new tasks. We take this to the extreme, automatically extracting 413,299 tasks from internet tables - orders of magnitude more than the next-largest public datas…

2023

Language Models Don't Always Say What They Think: Unfaithful Explanations in Chain-of-Thought Prompting

NeurIPS 2023poster

Large Language Models (LLMs) can achieve strong performance on many tasks by producing step-by-step reasoning before giving a final output, often referred to as chain-of-thought reasoning (CoT). It is tempting to interpret these CoT explanations as the LLM's process for solving a task. This level of…

2023

Pretraining Language Models with Human Preferences

ICML 2023oral

Language models (LMs) are pretrained to imitate text from large and diverse datasets that contain content that would violate human preferences if generated by an LM: falsehoods, offensive comments, personally identifiable information, low-quality or buggy code, among others. Here, we explore alterna…

2022

Red Teaming Language Models with Language Models

EMNLP 2022main

Language Models (LMs) often cannot be deployed because of their potential to harm users in hard-to-predict ways. Prior work identifies harmful behaviors before deployment by using human annotators to hand-write test cases. However, human annotation is expensive, limiting the number and diversity of…

2021

Case-based Reasoning for Natural Language Queries over Knowledge Bases

EMNLP 2021main

It is often challenging to solve a complex problem from scratch, but much easier if we can access other similar problems with their solutions — a paradigm known as case-based reasoning (CBR). We propose a neuro-symbolic CBR approach (CBR-KBQA) for question answering over large knowledge bases. CBR-K…

Cited by 81SourcePDFScholar
2021

Rissanen Data Analysis: Examining Dataset Characteristics via Description Length

ICML 2021spotlight

We introduce a method to determine if a certain capability helps to achieve an accurate model of given data. We view labels as being generated from the inputs by a program composed of subroutines with different capabilities, and we posit that a subroutine is useful if and only if the minimal program…

2020

Retrieval-Augmented Generation for Knowledge-Intensive NLP Tasks

NeurIPS 2020poster

Large pre-trained language models have been shown to store factual knowledge in their parameters, and achieve state-of-the-art results when fine-tuned on downstream NLP tasks. However, their ability to access and precisely manipulate knowledge is still limited, and hence on knowledge-intensive tasks…

2018

Visual Reasoning with Multi-hop Feature Modulation

ECCV 2018poster

Recent breakthroughs in computer vision and natural language processing have spurred interest in challenging multi-modal tasks such as visual question-answering and visual dialogue. For such tasks, one successful approach is to condition image-based convolutional network computation on language via…