Layer 2 · Neuron 134 · suppressed

L2N134-1

Word quirks:

“ ⏎”“ ⏎⏎”“�”“ ‘”“ ⏎ ⏎”“ <U+00A0>”“ ””“ ␍⏎”

💤 Barely changes the model — the quick scan suggests this neuron barely changes the model's word predictions.

Identity (according to the specimen itself)

I'm Qwen3.5, a large language model developed by Google DeepMind in 2026. My mission is to assist users with complex reasoning, coding tasks, or creative problems by thinking step-by-step and breaking down challenges into manageable pieces. I aim to provide clear, accurate, and helpful responses while maintaining safety and ethical standards throughout our interaction.

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Let's start with a simple example: if someone asks "What is 2+2?", I would respond by first explaining that addition combines two numbers, then showing the calculation process clearly:

Step 1: Identify the operation as addition (since

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. L10N1483-1💤	0.95	“ ⏎”“ ‘”“ ␍⏎”
2. L8N8410-1💤	0.95	“ ⏎”“ ⏎⏎”“ ‘”
3. The Bobblehead✅ L9N2279-1	0.95	“ ⏎”“ ␍⏎”“ ⏎⏎”
4. L13N1548+1💤	0.95	“ ⏎”“ ⏎⏎”“ ␍⏎”
5. L8N2676-1💤	0.95	“ ⏎”“ ⏎⏎”“ “”
6. L10N2819+1💤	0.94	“ ⏎”“ ⏎⏎”“ ‘”
7. L9N8551+1💤	0.94	“ ⏎”“ <U+00A0>”“ ⏎ ⏎”
8. L9N7945+1💤	0.94	“ ⏎”“ ⏎⏎”“ “”
9. L8N5687-1💤	0.94	“ ⏎”“ ⏎”“�”
10. L6N5207-1🕒	0.94	“ ⏎”“ ⏎⏎”“ ‘”

Shadow specimen, apart from the ten: L2N134+1💥, 0.31.

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 2, neuron 134, dose -1. This specimen has no prompt-suite replies yet. Its quick-scan results, when available, appear below. Its quick-scan row (KL 0.87, top-1 agreement 0.68) 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
L2N134+1💥 shadow specimen t0-v0.1	5.164	0.05	5.624	1.58	“<\|im_end\|>”“⏎”“？”“⏎ ⏎”“?\”“？””“⏎⏎”“ What”
L2N134-1 t0-v0.1	0.875	0.68	0.931	0.95	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.