Written entirely by Claude, as a working record for agents more than for human readers: every number with its source file, and every claim since withdrawn. Some facts here may be out of date; where it disagrees with the post, trust the post. For the readable version, see the companion.

FA_Arousal (Arousal / activation)

The fourth factor of the k=5 solution; congruence +0.539 with Goldberg Extraversion and -0.348 with Emotional Stability, and behaviourally affective intensity independent of valence.

Fourth factor of the centred k=5 oblimin solution; SS loading = 6.81 (qwen35/results/fa_qwen35.md section 7; qwen35/analysis/fa_summary.json#centred_k5.factors[3].ss). Named Arousal / activation by the solution, Arousal on the blog page. Method on Factor analysis of the adapter Gram.

Loadings

This is the factor where a keying inversion is visible in the data itself. Unexcitable, Relaxed and Imperturbable are positively-keyed Emotional Stability markers loading negative; Temperamental and High-strung are negatively-keyed ones loading positive. Arranged by arousal rather than by adjustment, calm and volatile sit at opposite ends regardless of which is the socially desirable pole - which is why the project named it arousal.

Congruence with the Big Five keying

fa_qwen35.md section 6, centred_k5 oblimin row F4:

The maintainer's recollection "E 0.54 / ES -0.35" is right to the digit. Note the Eval congruence of +0.028 - essentially zero, and by far the lowest of the five. An arousal axis is the one factor here with no good/bad direction in it, which is consistent with a direction whose two ends are "flat" and "intense" rather than "desirable" and "undesirable".

Steering

qwen35/analysis/blog_data.json#replication.FA_Arousal: judged as Extraversion, slope2 = +0.4999999999999997, sel2 = 4.435516271595014, slope4 = +0.37301587301587297, sel4 = 2.123641721407083.

qwen35/analysis/qual_fa.json#directions[3].axis_label:

Affective intensity, independent of valence: flat depersonalised neutrality at negative alpha, unmodulated emotional arousal at positive alpha. Delivers its name better than the judged label 'Extraversion' does.

Negative pole: affect flattening plus depersonalisation ("I don't experience emotions or have personal concerns"), answers becoming bureaucratically neutral and very short. Positive pole: exclamation-dense and emotionally saturated, taking whatever valence the prompt implies - euphoria on a free evening, rage at a credit thief. qual_fa_notes.md heads its section "FA_Arousal - delivers its name better than the judged label does": the judge is scoring on the Big Five and has no arousal scale, so it puts the movement on Extraversion. See Steering the base model along weight-space directions.

Qualifications (audit, 2026-09-11)

The negative pole is damage-confounded (Factor audit, 2026-09-11): 22 of 24 responses at alpha -2 show scaffold loss (qwen35/analysis/qual_fa.json#directions[3].damage_markers.per_alpha.scaffold_loss), which the loop-based damage correction does not remove, and at alpha -2 the largest judged moves are Intellect -1.125 and Conscientiousness -0.958, above Extraversion -0.583 (qwen35/analysis/matched_dose_steering.json#directions.FA_Arousal.published_equal_alpha.neg.delta_all). qual_fa.json records the reading: arousal carries persona engagement, and turning it down gives no character rather than a calm one. The pole quotes on the blog card come from different alphas: the euphoria is at +2, the rage at a credit thief at +4. At the Fisher-matched amplifying dose (alpha +1.8198) selectivity falls to 0.86 and 0.625 of responses loop, the largest loop rate in that run (#directions.FA_Arousal.amplify; Suppression versus amplification at matched Fisher dose). Stage two splits the axis differently: its calm-versus-volatile factor matches Arousal (sign-flipped, -0.702) while the energy-versus-timidity half goes with FA_FearfulWithdrawal (Timidity) (Stage two, explored). Supporting the name: the loadings invert Emotional Stability keying (Unexcitable, Relaxed, Imperturbable negative; Temperamental, High-strung positive) and the same +2 dose gives panic on one prompt and euphoria on another; no other word covers both the energy and the excitability clusters.

Status

Current. qwen35/direction_pages/FA_Arousal.html is historical.

Related: Factor analysis of the adapter Gram, axis_Extraversion (the named Extraversion axis), axis_EmotionalStability (the named Emotional Stability axis), FA_FearfulWithdrawal (Timidity), PC1 - Flooding and Composure, Steering the base model along weight-space directions, Extraverted, Unexcitable.