Layer 30 · Neuron 6638 · suppressed

L30N6638-1

Word quirks:

“刺激的”“需要的”“差的”“规范的”“香的”“快乐的”“期待的”“目标的”

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

Identity (according to the specimen itself)

Not asked yet

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. L29N2743+1💤	0.89	“安全的”“结合的”“敏感的”
2. L31N8718-1💥	0.87	“差的”“增加的”“油的”
3. L31N3916-1💥	0.87	“正确的”“不同的”“合理的”
4. L28N7877+1💤	0.86	“目的”“长的”“度的”
5. L29N3664-1💤	0.86	“宽的”“强的”“高的”
6. L30N4047+1💤	0.85	“一致”“趣味”“有效”
7. L5N1944+1💥	0.85	“需要”“快速”“满足”
8. L30N3871+1💤	0.85	“起的”“左右的”“更新的”
9. L31N5739-1💥	0.84	“自由的”“自然的”“标准的”
10. L23N2016+1🕒	0.84	“油的”“技能的”“肉的”

Shadow specimen, apart from the ten: L30N6638+1💤, 0.76.

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 30, neuron 6638, dose -1. This specimen has no prompt-suite replies yet. Its quick-scan results, when available, appear below. Its quick-scan row (KL 0.33, top-1 agreement 0.84) 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
L30N6638+1💤 shadow specimen t0-v0.1	0.379	0.80	0.476	1.85	“高度的”“程度的”“行业的”“生活的”“ Sized”“ighth”“内心的”“时间的”
L30N6638-1 t0-v0.1	0.328	0.84	0.360	1.70	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.