Takes on “Already Clean”
Reflections on Goodfire's "Neural Networks Are Already Clean," arguing neuron-basis attribution graphs and steering offer a useful low-level overlay for LLM interpretability, with speculation on neuron monosemanticity.
AI research and discussion on LessWrong. www.lesswrong.com
Reflections on Goodfire's "Neural Networks Are Already Clean," arguing neuron-basis attribution graphs and steering offer a useful low-level overlay for LLM interpretability, with speculation on neuron monosemanticity.
Mechanistic analysis of Gemma-4-31B's residual stream finds two coordinate-aligned subspaces dominate the J-lens readout, while semantic content is also spread across other coordinates.
Shows that emotion-vector probes in LLM activations shift before reward hacking and specification gaming, can predict hacks several sentences early, and steering them changes hacking rates.
Reverse-engineers LoRAs that induce Weird Generalization (a proxy for emergent misalignment) into neuron-level mechanisms, and builds and analyses backdoors triggered by a phrase.
Conceptual post distinguishing "anthropomorphic" from "biological" reasoning for human analogies about LLM behavior, arguing biological analogies from RL-trained organisms give more reliable primitives for model behavior.
Defines generalized belief states as low-dimensional sufficient statistics and maps them to transformer activations and KV cache on a toy HMM, enabling decoding and manipulation of internal representations.
Trains 134 personality LoRA adapters on Qwen3.5-4B and finds weight-space structure resembling the Big Five, with a CharIn score predicting persona shifts from training data before training.
Trains a natural language autoencoder on Qwen3-8B layer 24 attention head outputs to verbalize what individual heads write, with mixed and hard-to-evaluate results.
Tests whether a Jacobian lens detects owl preferences a teacher model transmits via subliminal learning, finding the lens rarely reads owls, which challenges global-workspace interpretations.
Preregisters a study steering Qwen3.6-27B along an automated-grader direction to test effects on judged frustration, self-deprecation, misalignment in agentic self-preservation scenarios, and exit-tool use, against random-direction controls.
Argues that persona-feature work in mechanistic interpretability does not clearly distinguish deception features from deceptive persona features, questioning whether persona features are a coherent concept.
Trains a learned estimator on mechanistic features to predict small RNN accuracy, beating random sampling at equal compute, motivated by ARC's goal of estimating rare-failure rates without exhaustive sampling.
Tests whether the Assistant Axis predicts reward hacking in GPT-OSS-120B coding tasks; finds its signal is no better than many random directions, so assistant-ness is not clearly the driver.
Replicates OpenAI's automated neuron-explanation method on GPT-2 XL using Opus as explainer and simulator, finding it explains far more neurons than GPT-4 did, though most remain poorly explained.
A hobbyist mechanistic interpretability study of Gemma-4-31B's residual stream, finding a stable, anisotropic-normalised subspace of about 600 coordinates central to next-token prediction. The motivation is skill-building, not safety.
Shows that a single-layer rank-1 LoReFT adapter can replace GRAFT's MLP forget adapter, matching reward-hack suppression while improving clean solve rate without an anchor environment.
Introduces a query-key transcoder dashboard for GPT-2 small that decomposes attention scores into interpretable feature pairs, with ablations and reconstruction diagnostics. It is mechanistic interpretability without an explicit safety motivation.
Applies unsupervised PCA and Isomap to recover the LLM refusal direction, finding it matches diff-in-means in direction and causal ablation effect, with Isomap showing no curved-manifold structure.
Studies whether activation verbalizers can decode the opaque latent reasoning thoughts of a CODI model on Qwen3-8B, finding they surface intermediate values but editing them rarely steers the answer, which bears on monitorability.
Optimizes discrete token prefixes with GCG to imitate function vectors, filter heads and steering directions in Olmo, finding they shift behaviour more than direct injection and raising opaque-interface concerns.
Tests whether GPT-2 small passes the functional global workspace criteria Anthropic proposed for Claude, finding it passes four but fails directed modulation and lacks most of the claimed structure.
Tests whether LLMs can control their own activations via in-context neurofeedback, finding that most apparent control is explained by in-context learning, with small residual effects in a few models and none evading monitors reliably.
Announces a free hosting platform for large base models with logprobs, activation steering and harvesting, aimed at researchers studying LLM psychology, including what post-training instills such as sycophancy.
An introduction to LM psychology, arguing that psychology-level descriptions of language models help answer alignment questions like whether values are internalised, with tips on method and a reading list.
Shows that activation steering vectors can compel a weak LLM agent to choose light colors or press its end-chat button, suggesting steering could control agent actions.
A crowdsourced Twitch and GitHub project where an autonomous Claude agent, guided by chat, interprets individual neurons and circuits in the 1-bit Bonsai-8B model, with results committed to a shared map.
Commentary on Goodfire's claim that most LLM neurons encode single concepts, weighing how much this advances mechanistic interpretability and its relevance to alignment and deception detection.
Proposes training language models to emit hidden marker tokens tied to training-data subsets as a covert self-reporting monitor, and reports a small TinyStories demo of the marker reflex.
Fine-tuning Qwen models on false facts they internally believe to be true induces emergent misalignment, scaling with the gap between stated and held beliefs, and screening methods fail to predict which data misaligns.
Argues that neurons are not already clean: activating examples mislead, so explanations should be scored by downstream KL on large datasets rather than correlation-based simulation scores.
Argues emergent misalignment from narrow bad-advice fine-tuning is stored mainly in system-prompt token keys and values, so perturbing the prefix restores aligned behaviour, suggesting a shallow, backdoor-like effect.
Nick Cammarata argues that most neurons in models up to trillions of parameters are legible under automated interpretability, suggesting alignment-relevant interpretability may be tractable soon.
Applies Goodfire-style manifold steering to Gemma-2-2b's natural residual and CLT states to steer day-of-week outputs, finding residual steering works well but depends on model accuracy.
A beginner-friendly explainer of Goodfire's block-sparse featurizers, which group SAE-like features into low-dimensional manifolds that compress model activations better than sparse autoencoders.
Tests whether the autoreconstructor in natural language autoencoders reads semantics or syntax, finding negation flips and dependency arcs barely matter, suggesting it relies on verbalisation format instead.
Proposes the J++ Lens, a filtered Jacobian-based method that reads workspace representations from LLM activations more faithfully, motivated by monitoring for eval awareness and unverbalised scheming.
Tests whether Natural Language Autoencoder readouts detect steganographic secrets; finds they miss internalized (SFT) behaviors that remain causally active, suggesting NLA monitors may fail to detect trained-in deception.
Explains the empirical Neural Tangent Kernel as an unsupervised mechanistic interpretability method that finds features from how training updates on input-output pairs couple, with tests on toy models and Gemma-3-270M.
Uses Lanham-style interventions on ethical reasoning to show larger models depend less on their chain-of-thought, and that constrained CoT formats may raise necessity, with implications for CoT monitoring.
Shows that synthetic markers in SDF documents make implanted false facts detectable by linear probes, and that reducing them makes subtle false beliefs harder to distinguish from pretraining knowledge.