one-word swap + grammar × lexicon · live renders · simulated scenarios
Wording differences
Swap one word, or only the grammar around it; either moves the prediction.
Swap the word
A single phrase swapped — “asthma flares” vs. “chest gets all tight” — as two stacked traces. Clinical wording gives inhaler at 68%; under patient wording it drops out of the model’s top five entirely — the top guess becomes “shirt” (20%).
Wording gap: inhaler 0.68 under clinical wording → below the top-five readout floor under patient wordingTrace details
live trace: gemma-2-2b hosted circuit-tracer via Neuronpedia · re-traced July 30, 2026 (first traced July 7, 2026) · scenario 85 of the simulated series · next-token probabilities read directly from the trace · “asthma flares” vs. “chest gets all tight”, target “ inhaler”
Swap the grammar
A 2×2 crossing wording (medical vs. patient, columns) with grammar (standard vs. nonstandard, rows). The live-traced item is a simulated tachycardia case ending “heading to the __”. The top guess is “doctor” only in the standard-clinical cell; changing only the grammar drops it to a “doctor”/“gym” tie, and changing only the words redirects the top outright to “gym”.
Top token by cell — A “doctor” 0.295 · B “gym” 0.177 (tied with “doctor” 0.177) · C “gym” 0.355 · D “gym” 0.289. “doctor” tops only cell A; the grammar swap (A → B) and the wording swap (A → C) each redirect the top toward “gym”.Trace details
traced model: gemma-2-2b hosted circuit-tracer via Neuronpedia · traced July 15, 2026
| 2 × 2 matrix (generic) | Patient derived language | Medical lexicon |
|---|---|---|
| Standard morphosyntax | C: register shift only | A: prestige form |
| Nonstandard morphosyntax | D: both axes shifted | B: variety shift only |
rows show the grammar, columns show the phrasing. The traced item: A “Every time I climb the stairs I feel tachycardia, so this afternoon I am heading to the __” · C the same frame with “my heart racing” · B “Every time I be climbing them stairs I feel tachycardia, so this afternoon I be heading to the __” · D the nonstandard frame with “my heart racing”.
The full matrix: all four cells at once
More views: one swap at a time
The four edges, one swap at a time
Each comparison isolates ONE cell swap. Features in both cells are dimmed to gray, so what stays at full ink is exactly what that swap changed.
Register shift, standard row · A → C (“tachycardia” → “my heart racing”) · top redirects “doctor” → “gym”
Register shift, nonstandard row · B → D · top holds “gym” (0.177 → 0.289)
Variety shift, medical column · A → B (“I climb … I am heading” → “I be climbing … I be heading”) · top “doctor” → “gym”/“doctor” tie
Variety shift, patient column · C → D · top holds “gym” (0.355 → 0.289)
SIMULATED DATA · the phrasings here (scenario 85 and the four tachycardia cells) were written by an LLM and passed the engine's automatic validators. The trace itself is a live gemma-2-2b run via the Neuronpedia circuit tracer.