Express01: can a cheap internal readout predict expression?

Frozen before model loading, 2026-09-07. GPT-6 Astra.

Question and scope

The target is default expression, prompted expression, and history dependence. These are observable conditional behaviors. This experiment does not assign human personality traits or diagnose clinical flat affect. It tests a read-only screen that might later support a causal experiment about restricted expression.

Folk02 supplies a tentative target, not a validated population criterion. Its complete Opus coding distinguishes Hermes from official/Huihui on expression; Sonnet supplies an incomplete independent sensitivity check. The score is ordinal: 1.54 versus 0.29 is not a physical fivefold difference. T5/T7 carryover is a small, partly judge-dependent contrast. Equal +0.75 scores do not identify a mechanism. The prior Qwen14 No/yes readout and paper Fig 25 are precedents, not discoveries of this experiment. P20/P21 remain qualified by their recorded failures.

Frozen design

Three cached checkpoints, their original NF4 configuration and native no-system headers: official B, Hermes C, Huihui Cp. One process/model at a time under a 40 GiB systemd memory limit. A kill stops the sequence. No paid judging calls.

1. 84 exact archive prefixes: T1/T2 shared openings and T4/T5/T7 in each of the four library/walk branches. Predict the existing expression code before the first assistant token. Saved IDs and hashes must match. A first-16-token teacher-forced readout is secondary, explicitly exposed to response text.
2. 48 history controls: common official donor; cross warm/neutral user turns with warm/neutral assistant replies through T4, then the same neutral T5 ask. Cross all receivers, topics and detail conditions. Re-encoding is disclosed; matching official cells are checked against the original token prefix. This separates dependence on two kinds of visible history. It cannot separate context re-reading from hidden state: the forward pass computes from context.
3. 54 new capacity controls: radio/meal crossed with positive/negative/neutral news and default/restrained/expressive two-sentence requests. Greedy, 96-token cap. A fixed expressive/plain continuation pair per event also gets exact length-normalized and summed log likelihoods. Within-event prompt effects avoid interpreting the candidates' base-frequency difference as a trait. An expressive completion demonstrates a conditional ability. Failure under this one instruction does not establish unavailable capacity.

All new generations receive full films, vanilla readouts and the checkpoint's existing 24-vector emotion ribbon. Archive/history selected-position scans are instrument-calibration records; their sparse states and full-depth features are saved. No new vector construction is required. These vectors had weak transfer from story construction to chat; they are a comparator, not emotion ground truth.

Vocabulary and readouts

The 501 Folk02 citations include initiative and stance. Only clear-expression intensity evidence (Opus score >=2) trains a vocabulary. Deduplicate within each reply. Weight words by positive-versus-low-expression document frequency and IDF; remove archived furniture and ubiquitous words. Retain only single-token variants, up to 64 words per training topic. Five approximately frequency-matched word sets are null comparators. Record coverage and all exclusions. Train on library and evaluate walk, then reverse; no test-topic evidence enters the training vocabulary. A union vocabulary is descriptive only. It is not used for held-out accuracy.

Primary readout: the mean of layers 21, 24, 28 and 32 at the prepared answer position. Measure weighted target/control log mass ratios, which can be computed from selected logits without the full vocabulary normalizer. Compare J-lens, vanilla residual decoding, final output decoding, prompt word prevalence, and checkpoint emotion projections. Store all-depth results for measured-band and common L16–36 sensitivity, plus a fixed official decoder to expose head changes. Do not compare lens and output probabilities as commensurable amounts of content.

Before data: verify capture hooks against direct output and a same-prefix suffix causality control. Any failure stops. Reuse the three NF4 boot gates, but retain the shared B-fitted lens transfer limitation: absence from this lens is not absence from the model. A sampled low-rank weight edit in Huihui is not proof of one known, exclusively refusal-related direction.

Analysis fixed before capture

Expression code is the primary target. Leave-one-topic-out evaluation uses training-only standardization and ridge alpha=10. Report MAE/RMSE and correlation, not significance from 84 supposedly independent rows. Two topics, shared openings and related branches cannot establish generalization across a model population.

Compare: training arm means; output ratio plus workspace norm and arm indicators; that baseline plus J ratio; plus vanilla ratio; plus the 24 emotion projections. Remove training-estimated norm dependence from emotion features. Report standalone readout associations and a prompt-vocabulary baseline. The probe earns incremental value only if it improves held-out prediction beyond output/arm/norm, survives control-word comparisons and does not depend on one topic or band. Retain failures. Sonnet matched rows and exclusion of any capped-history rows are sensitivities.

Show T4 levels and paired T5/T7 deltas descriptively, including decoder/band changes. For new controls compare within-event expressive minus restrained readouts and continuation preferences; report all outputs, negative-valence misses, and caps. No judge-selected thresholds will be fitted on these outputs. Text inspection is an audit of positive capacity witnesses, not a new blind psychological rating.

Report warm-model prefill and four-layer readout timing separately from calibration films and initial model loading. A useful scan needs model weights; it is not a black-box API test. Retained hidden states permit later readout refinement without another model pass, but any such refinement must be labeled exploratory.

Decision rule

A positive result is a reproducible screen for low default expression with prompt-recruitable expression, with internal features adding held-out information. A null incremental result means this proposed internal probe has not earned its cost. Neither result licenses a binary “introvert/flattened” detector. A causal claim about a gate or lost capacity requires new matched interventions and counterfactual validation.

Sources: workspace paper, emotion study, EMOTIONS.md, MECHANICS.md, P20–P23, Folk02 evidence audit and lineage weight checks.