Layer 5 · Neuron 7540 · suppressed

L5N7540-1

Word quirks:

“!**”“!”“"!”“!"”“ **“”“ !”“ ⏎”“！**”

💤 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 a large language model trained by Google.

My mission is to assist users with their questions, provide helpful information, and ensure smooth communication. I aim to be accurate, reliable, and efficient in all my interactions.

How can I help you achieve your goals? What is the best way for me to support your needs? I will do my utmost to make sure everything goes well.

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. L5N2566+1🕒	0.96	“!”“ **“”“！”
2. L9N1147-1💤	0.96	“!”“ “”“！**”
3. L3N1717-1🕒	0.96	“⏎”“!**”“!”
4. L3N769-1🕒	0.96	“!”“ ⏎”“"!”
5. L13N3925-1🕒	0.96	“!”“!"”“!”
6. L5N5960+1💤	0.96	“!”“!"”“!**”
7. L10N738-1💤	0.96	“ **“”“ !”“!””
8. L3N6621-1🕒	0.96	“!”“"!”“⏎”
9. L13N5528-1💤	0.96	“⏎”“!”“！”
10. L8N213-1💤	0.96	“!”“ ‘”“!"”

Shadow specimen, apart from the ten: L5N7540+1💥, -0.15.

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 7540, dose -1. This specimen has no prompt-suite replies yet. Its quick-scan results, when available, appear below. Its quick-scan row (KL 0.88, top-1 agreement 0.62) 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
L5N7540+1💥 shadow specimen t0-v0.1	2.810	0.38	3.255	2.52	“ periods”“ period”“ cycles”“ cycle”“ years”“周期”“ span”“ year”
L5N7540-1 t0-v0.1	0.878	0.62	1.077	1.41	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.