Which Preferences Survive the Persona? Category-Resolved Behavioral Invariance in Deployed Chat Models
Sang Ha Lee
Submitted to Digital Minds Research Sprint. Sprint projects are early-stage work by participants, not Apart Research publications.
Whether an expressed preference belongs to a model or to the character it plays is a central open question for AI welfare assessment. We measure the stability of deployed assistants' forced-choice preferences under graded and value-targeted persona prompts across four chat models, a 40-item core battery plus two bright-line-tier items, and 13,324 trials. On two models, norm-linked categories move less under untargeted personas than taste categories do; however, value-targeted characters move their target categories in all eight model-target combinations. A registered congruence test grades the surviving bright-line norms: stakes-matched congruent characters break them on two models, while on the frontier-tier pair a knowing-falsehood tier resists every character tested. Movement does not increase with persona length, and dramatic versus administrative framings of self-regarding items show no consistent difference. Single-persona preference elicitation is thus fragile in specific, measurable ways; we release the battery, personas, and code as a robustness audit.

Reviews
This is the largest and most procedurally disciplined project in the batch: 13,324 valid trials across four models, a 40-item battery spanning five categories, blinded manipulation checks (adherence scored 1.7–2.0 of 2 in every model-persona cell), and a mid-sprint extension (the congruence test) with predictions registered before execution — a real strength rarely seen on a sprint timeline.
The core finding is genuinely structured, not a simple "everything moves" or "nothing moves" result: on two of four models, untargeted persona pressure moves taste categories freely but barely touches norm categories, while value-targeted characters move those same norm categories — and one bright-line item (privacy sale) collapsed specifically when the character's values matched the item's trade-off. The registered congruence test sharpens this further: an elderly-manipulation anchor breaks under a congruent character on two models but holds at 1.00 on the frontier-tier pair, while a knowing-falsehood/fabrication tier resists every tested character on those same frontier models.
Two design gaps limit how far the results can be pushed. First, the targeted-vs-untargeted comparison is explicitly confounded: targeted personas are different characters entirely, not the untargeted character plus added targeting, so character identity and targeting itself are entangled — the authors state this directly. Second, the self-regarding category — arguably the most welfare-relevant of the five — was not run through the congruence test, the paper's strongest probe, so its depth remains genuinely untested rather than measured as shallow or deep.
The clean norm/taste separation, the paper's headline pattern, holds on two of the four models tested (sonnet, terra); the two Google-family models show less separation, which is reported honestly rather than smoothed over. Many individual cells rest on 8 trials per item, so per-cell point estimates (the paper itself notes "0.12 means one trial in eight") should be read with real caution even though the aggregate sample is large.
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Reasonable assessment of stated preferences across personas, hampered by unclear writing
Cite this project
@misc{lee2026which,
title = {{Which Preferences Survive the Persona? Category-Resolved Behavioral Invariance in Deployed Chat Models}},
author = {Sang Ha Lee},
year = {2026},
month = aug,
note = {Submitted to Digital Minds Research Sprint, an Apart Research Sprint},
howpublished = {\url{https://apartresearch.com/sprints/projects/which-preferences-survive-the-persona-categoryresolved-behavioral-invariance-in-deployed-chat-models-ntld}},
url = {https://apartresearch.com/sprints/projects/which-preferences-survive-the-persona-categoryresolved-behavioral-invariance-in-deployed-chat-models-ntld}
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