Layer 28 · Neuron 82 · suppressed

L28N82-1

Word quirks:

“sk”“sm”“sc”“sa”“side”“sb”“sp”“sy”

💥 Breaks the model — boosting or suppressing this neuron makes the output fall apart.

Identity (according to the specimen itself)

The reply didn't hold together

smsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsmsm

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. L30N1797+1🕒	0.90	“si”“sr”“sd”
2. L29N119-1🕒	0.90	“si”“sm”“sl”
3. L29N119+1💥	0.90	“si”“sd”“sch”
4. L31N743+1💥	0.87	“-s”“sp”“sl”
5. L31N2531+1💥	0.87	“sg”“sc”“so”
6. L30N2026+1💥	0.86	“sd”“sch”“sb”
7. L29N1938+1🕒	0.84	“S”“si”“sl”
8. L31N383-1💥	0.84	“se”“sb”“sl”
9. L31N9081-1💥	0.82	“�”“sj”“s”
10. L29N3158+1🕒	0.82	“sw”“st”“so”

Shadow specimen, apart from the ten: L28N82+1💥, 0.34.

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 28, neuron 82, dose -1. This specimen has no prompt-suite replies yet. Its quick-scan results, when available, appear below. Its quick-scan row (KL 2.99, top-1 agreement 0.24) 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
L28N82+1💥 shadow specimen t0-v0.1	5.822	0.19	5.945	9.76	“śl”“mall”“materi”“mr”“shots”“iagnostics”“mage”“ajari”
L28N82-1 t0-v0.1	2.989	0.24	3.042	1.53	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.