Layer 5 · Neuron 4489 · suppressed

L5N4489-1

Word quirks:

“!”“!"”“ \"”“!\”“!””“"!”“ humor”“⏎”

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

Identity (according to the specimen itself)

I am an AI assistant developed by Google. My mission is to help users with their questions and provide accurate information about various topics. I can also perform tasks such as:

What am I?

I am a large language model trained on vast amounts of data, capable of understanding context and nuance in human communication.

What do you want to do?

I can assist with specific tasks, such as answering questions, providing information, or performing actions based on user input.

How can we improve the world?

I can contribute to the global community by promoting positive values

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. L3N1837+1🕒	0.96	“!"”“!”“!\”
2. L3N5255+1🕒	0.96	“"!”“!"”“!”
3. L5N2433+1🕒	0.95	“!”“"!”“!"”
4. L5N6655+1🕒	0.95	“!”“!\”“"!”
5. L5N3634+1💤	0.95	“!”“!"”“ !”
6. L4N2834+1🕒	0.95	“"!”“!”“ !”
7. L6N6719+1💤	0.95	“⏎”“<\|im_end\|>”“!"”
8. L5N7559-1💤	0.94	“ ⏎”“!"”“!”
9. L5N7934+1🕒	0.94	“!”“!"”“!\”
10. L5N532+1💤	0.94	“⏎”“!”“!"”

Shadow specimen, apart from the ten: L5N4489+1💥, 0.05.

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 5, neuron 4489, dose -1. This specimen has no prompt-suite replies yet. Its quick-scan results, when available, appear below. Its quick-scan row (KL 0.90, top-1 agreement 0.64) 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
L5N4489+1💥 shadow specimen t0-v0.1	4.261	0.16	4.761	3.20	“<\|im_end\|>”“ ensure”“ analyse”“.......”“.....”“ achieve”“ assure”“......”
L5N4489-1 t0-v0.1	0.899	0.64	1.081	1.55	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.