Layer 29 · Neuron 8399 · boosted

L29N8399+1

Word quirks:

“ A”“秦”“_a”“ a”“ а”“ aesthetic”“A”“*A”

🧪 In testing — Answered 0 of 8 prompts so far.

Identity (according to the specimen itself)

The reply didn't hold together

Aa* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a a* *a **

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. L26N7933-1🕒	0.96	“ A”“ a”“秦”
2. L26N6723-1🕒	0.95	“秦”“ A”“ а”
3. L29N6463-1🕒	0.95	“ A”““A”“a”
4. L30N3021-1💥	0.95	“a”“A”“ A”
5. L30N8946+1💥	0.95	“a”“A”“ A”
6. L25N461-1🕒	0.95	“秦”“ A”“*A”
7. L31N473-1💥	0.94	“a”“A”“ A”
8. L27N3178+1🕒	0.93	“ A”“秦”“ А”
9. L29N2817+1💥	0.93	“ a”“ A”“ а”
10. L27N3079+1🕒	0.93	“ A”“A”“⇥A”

Shadow specimen, apart from the ten: L29N8399-1💤, 0.11.

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 29, neuron 8399, dose +1. This specimen has no prompt-suite replies yet. Its quick-scan results, when available, appear below. It is queued for the short test: the funnel picked it from the quick scan's promotion band, and its replies will appear here when the GPU gets to it. 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
L29N8399+1 t0-v0.1	1.077	0.55	1.156	1.17	Top boosted tokens ↑
L29N8399-1💤 shadow specimen t0-v0.1	0.267	0.83	0.306	1.47	“EH”“ eh”“aders”“-action”“ Action”“ EH”“orii”“Action”

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.