Layer 6 · Neuron 955 · suppressed

L6N955-1

Word quirks:

“<|im_end|>”“?...”“...\”“?\”“...”“⏎”“?!”“...**”

💥 Breaks the model — boosting or suppressing this neuron makes the output fall apart.

Identity (according to the specimen itself)

I am an AI assistant who cannot determine the specific intent of the user's question. I will try my best to provide a clear and concise answer to the following:

Clarify the context: If you are asking about the purpose of this message, it is to clarify the context of the user's question.
Provide a clear and concise answer: I will try my best to provide a clear and concise answer to the following:

Clarify the context: If you are asking about the purpose of this message, it is to clarify the context of the user's question.
**

Nearest neighbors

Specimens with similar replies or word quirks. Similarity runs from −1 to 1; 1 is identical. These are leads, not shared mechanisms. How profiles are built.

By word quirks Profile recipe

Specimen	Similarity	Word quirks
1. L11N807+1💤	0.99	“<\|im_end\|>”“⏎”“?\”
2. L2N1828+1💥	0.96	“<\|im_end\|>”“?\”“?!”
3. L1N914-1💥	0.96	“<\|im_end\|>”“⏎”“...\”
4. L5N7028-1🕒	0.95	“<\|im_end\|>”“...\”“?...”
5. L5N2564+1🕒	0.95	“<\|im_end\|>”“⏎”“?\”
6. L4N6281+1🕒	0.95	“...”“!”“<\|im_end\|>”
7. L3N4757-1🕒	0.95	“<\|im_end\|>”“?...”“⏎”
8. L4N20+1🕒	0.95	“<\|im_end\|>”“⏎”“...\”
9. L5N9154+1💥	0.95	“...”“<\|im_end\|>”“...\”
10. L11N5688-1🕒	0.95	“<\|im_end\|>”“?...”“⏎”

Shadow specimen, apart from the ten: L6N955+1💤, 0.52.

Cousins · specimens sharing a neuron

No specimen with replies shares this neuron yet.

Technical details

Quick scan: measure prediction shifts on fixed reference text. Short test: generate replies to a small set of prompts. Longer test: extend to a larger set. Full test: run the full prompt suite. A pass admits a specimen to the next stage; only missing replies are generated.

Layer 6, neuron 955, dose -1. This specimen has no prompt-suite replies yet. Its quick-scan results, when available, appear below. Its quick-scan row (KL 2.52, top-1 agreement 0.42) is outside the band that feeds the short test (KL 1 to 2.5, agreement 0.5 to 0.65), so it stays at the quick scan unless someone queues it by hand. A hand pick goes straight to the full test. See Method for the tiers.

Quick scan · prediction measurements

Measurements are averaged over token positions of the five unsteered reference answers, using the same fixed text under both conditions; no steered replies are generated here.

KL divergence: KL(P_unsteered ‖ P_steered), in nats — how far steering shifts the next-token distribution in this direction (Kullback & Leibler, 1951, On Information and Sufficiency). Unsteered ≈ 0.001.
Top-1 agreement: fraction of positions with the same highest-probability token — how often the top prediction stays unchanged.
ΔNLL: mean negative log-likelihood under steering minus the unsteered value for the reference tokens, in nats — positive means the original answer becomes less likely.
Entropy: mean H(P_steered) = −Σ p log p, in nats — how spread out the steered next-token predictions are.

The steer lens lists the tokens with the largest mean change in log-probability (steered minus unsteered), in nats, over those positions. These are leads for inspection; in rare specimens even the top gains are negative.

Setting	KL divergence	Top-1 agreement	ΔNLL	Entropy	Steer lens
L6N955+1💤 shadow specimen t0-v0.1	0.515	0.71	0.657	1.36	“⏎”“ ‘”“ '”“ \"”“ ⏎”“⏎ ⏎”“ ‚”“‘”
L6N955-1 t0-v0.1	2.523	0.42	2.934	2.25	Top boosted tokens ↑

Method

A specimen is a fixed steering configuration of Qwen3.5-4B: one MLP neuron or a pair, each with a signed dose. Unsteered is the control. L identifies the layer; N, the neuron.

Additive activation steering. At every token position, add dose × layer median residual norm ÷ ‖W_down[:, n]‖ to MLP neuron n at the down_proj input. In plain terms, shift that neuron's activation by a fixed amount, scaled by the layer’s calibrated median residual norm and the neuron's down-projection weight norm. Positive doses push up; negative doses push down. Dose is normalized intervention size, not a percentage or probability.