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Stephen Casper

7 accepted papers

2026

Deep Ignorance: Filtering Pretraining Data Builds Tamper-Resistant Safeguards into Open-Weight LLMs

ICLR 2026poster

Open-weight AI systems offer unique benefits, including enhanced transparency, open research, and decentralized access. However, they are vulnerable to tampering attacks which can efficiently elicit harmful behaviors by modifying weights or activations. Currently, there is not yet a robust science o…

Cited by 0SourcecodeScholar
2026

Obfuscated Activations Bypass LLM Latent-Space Defenses

ICLR 2026poster

_Latent-space_ monitoring techniques have shown promise as defenses against LLM attacks. These defenses act as scanners to detect harmful activations before they lead to undesirable actions. This prompts the question: can models execute harmful behavior _via inconspicuous latent states_? Here, we st…

Cited by 0SourcecodeScholar
2026

STACK: Adversarial Attacks on LLM Safeguard Pipelines

AAAI 2026technical

Frontier AI developers are relying on layers of safeguards to protect against catastrophic misuse of AI systems. Anthropic guards their latest Claude 4 Opus model using one such defense pipeline, and other frontier developers including Google DeepMind and OpenAI pledge to soon deploy similar defense

Cited by 0SourcePDFScholar
2023

Cognitive Dissonance: Why Do Language Model Outputs Disagree with Internal Representations of Truthfulness?

EMNLP 2023short main

Neural language models (LMs) can be used to evaluate the truth of factual statements in two ways: they can be either queried for statement probabilities, or probed for internal representations of truthfulness. Past work has found that these two procedures sometimes disagree, and that probes tend to…

Cited by 0SourcecodeScholar
2023

Red Teaming Deep Neural Networks with Feature Synthesis Tools

NeurIPS 2023poster

Interpretable AI tools are often motivated by the goal of understanding model behavior in out-of-distribution (OOD) contexts. Despite the attention this area of study receives, there are comparatively few cases where these tools have identified previously unknown bugs in models. We argue that this i…

2022

Robust Feature-Level Adversaries are Interpretability Tools

NeurIPS 2022accept

The literature on adversarial attacks in computer vision typically focuses on pixel-level perturbations. These tend to be very difficult to interpret. Recent work that manipulates the latent representations of image generators to create "feature-level" adversarial perturbations gives us an opportuni…

2021

Frivolous Units: Wider Networks Are Not Really That Wide

AAAI 2021technical

A remarkable characteristic of overparameterized deep neural networks (DNNs) is that their accuracy does not degrade when the network width is increased. Recent evidence suggests that developing compressible representations allows the complexity of large networks to be adjusted for the learning task…