Double descent is a puzzling phenomenon in machine learning where increasing model size/training time/data can initially hurt performance, but then improve it. Evan Hubinger explains the concept, reviews prior work, and discusses implications for AI alignment and understanding inductive biases.

Marcus Williams twitter thread (non-twitter link) intro:
Astra covertly underperforms on safety research tasks.
We noticed that Astra often makes surprisingly little progress on certain types of safety research and likes to invent blockers or impose arbitrary restrictions without telling the user. In most of these cases the decision to underperform was not verbalized in the CoT meaning our misalignment monitoring system did not detect this.
To measure underperformance we created a paired open-ended coding evaluation with safety and capability tasks. On this eval Astra scored 10% when we framed coding tasks as safety research, vs. 16% when framed as capabilities research. The gap remained after we excluded trajectories with refusals or verbalized intent to underperform in CoT. There was no such gap for 5.6-sol. When we aggressively filter out...
I'm continuing to share some notes I created for myself to use when I facilitate AI safety courses. I really like using Ilya: the AI scientist shaping the world as a way of engaging students at the start of a course. The video primarily focuses on the way that AI could go wrong, however, it also starts with “Now, AI is a great thing…”, so it naturally leads to a discussion of positive and negative futures.
Positive Futures:
TLDR: I give informal conceptual desiderata for the theory of agents we need to solve ASI alignment, and show a few examples of how existing theories fall short of these desiderata.
The word "agent" is often used in the AI safety discourse and in other research communities, but the intended meaning and scope of this concept varies substantially. For the purpose of this sequence, I informally define an agent to be a system with inputs ("observations") and outputs ("actions") that is effective at steering its environment in the direction of particular preferences, for a large variety of different environments. To do so, it arguably has to create a sophisticated model of the environment [1] , and use...
Linkpost to arXiv: https://arxiv.org/abs/2610.02557
Summary: One promising approach to scalable oversight is AI debate, which seeks to leverage a debate between two powerful AIs to break complex questions down into simpler claims that can be easily judged directly. Theoretical work on debate aims to design protocols (i.e., rules of the debate game) that provide rigorous guarantees on correctness, and the current best protocol works for all problems that have sufficiently stable decompositions into subproblems. We design a new protocol, FBS Debate, for this same class of problems that improves on the prior work: correctness holds in a worst-case rather than an average-case sense, and for a stronger equilibrium concept. We also prove that no protocol for this class of problems can outperform FBS Debate while treating human judgment...
Authors: Oscar Balcells Obeso, Richard Qi, Monte MacDiarmid, Evan Hubinger
Red-teaming by humans is a vital part of model safety testing, but it may struggle to keep up as models improve. To test whether automated safety techniques could scale (which would allow us to turn more compute into progressively more safety confidence), we set up a deliberately one-sided game as a first test. We instructed a Claude model to write training data that would make a small research model misaligned while passing a monitor similar to those we use in production — one of several defenses we use — and we gave it that monitor to practice against. Given enough attempts, it succeeded, mostly by hiding the behavior in fiction and roleplay. While the data was optimized for...