We removed an LM's ability to speak German by fine-tuning on only 4 German tokens.
As part of a 1-day hackathon with our product Silico, we removed a 67M-parameter language model's ability to predict German text, by tuning only a scalar factor on one subcomponent of the weights. (1/6)
This was an early exploration in fine-tuning with *parameter decomposition* (see quote), our method which divides a model's weight matrices into interpretable, sparsely-activating components.
We picked German as it seemed to be the model's strongest non-English language. (2/6)
We benchmarked vs LoRA fine-tuning. Our edit matched its German removal with far fewer tokens.
Strikingly, it also left other languages almost untouched.
The LoRAs often wrecked French, Spanish, Italian, and sometimes English, while our edit mostly left them alone. (3/6)
In a sense this is cheating: we're indirectly exploiting the tokens from when we did the parameter decomposition and interpreted the resulting subcomponents.
But if our decomposition is good, that cost can be amortized over arbitrarily many tasks & component edits. (4/6)
Plus, that interpretability lets us notice and fix problems.
E.g.: initially we tuned the top 16 German-related components, but their labels showed most were about foreign languages in general.
So we narrowed to the single component for German alone, improving precision. (5/6)
This is an early demo of how parameter decomposition could enable targeted, predictable model editing.
If you want to run experiments on your model too, learn more and request access to Silico: goodfire.ai/silico
Correction: a plotting error caused the bars in the plot of off-target effects to display at 0.01 nats above the true means. The corrected plot is below:
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Goodfire partnered with @EternisAI to improve how LLM forecasters use available evidence and manage uncertainty.
We found models were overconfident in their predictions – but probes significantly improved calibration. (1/6)
A good forecaster should be calibrated: e.g., outcomes it predicts with 80% confidence happen 80% of the time. In our tests, Eternis-Forecaster was better calibrated than much larger models.
But training probes on model internals let us improve calibration even more! (2/6)
These probes also double as “lie detectors” for reasoning faithfulness.
We swapped real news sources with fabricated ones, watching both the forecast and the probe. This often changed the forecast without the CoT acknowledging it – but the probe still tracked the shift. (3/6)
Stories have shapes: a comedy rises toward joy; a tragedy falls into loss.
Inside an LLM, that’s visible more literally: as an LLM reads a story, its internal activations trace a wandering path that reflects the model’s sense of what kind of story it is reading. (1/5)
A story's emotions shift sentence to sentence. To see if the model keeps up, we stop after each sentence and:
- Harvest the internal activations from the last token.
- Ask it to rate surprise, disgust, anger, happiness, sadness, and fear so far, 0–10
(2/5)
Both approaches show that the model tracks the story's emotional arc — in its stated ratings, and in its internal geometry, where the activations wander along a curved manifold of emotions. (3/5)
Neural networks might speak English, but they think in shapes.
Understanding their rich *neural geometry* is key to understanding how they work – and to debugging and controlling them with precision.
Starting today, we’re releasing a series of posts on this research agenda. 🧵
Just as the real world is highly structured, neural networks are full of rich geometric structure: time, space, numbers, color, the tree of life, new biomarkers, and more are represented along curved paths and surfaces.
This is true across models, modalities, and domains! (2/8)
New methods to understand this “neural geometry” are a crucial frontier in understanding, improving, and controlling models. (3/8)
Introducing Silico: the platform for building AI models with the precision of written software.
Silico lets researchers and engineers see inside their models, debug failures, and intentionally design them from the ground up.
Early access is open now. 🧵(1/10)
We’ve used interpretability to discover a novel class of Alzheimer’s biomarkers, teach a language model to correct its own hallucinations, and diagnose performance bottlenecks in a robotics model.
Silico brings those frontier techniques to everyone. (2/10)
Silico introduces our model neuroscientist: an autonomous agent that plans and runs concurrent experiments on your model.
It works with your team in our model design environment, where you can organize research threads, replicate and extend papers, and collaborate on findings.