Justin and Chase Hudson have done something the HRIS framework needed: they've run the experiment.
In HRIS Validation I: Stability Under Perturbation, they present a reproducible ten-trial protocol designed to test whether an induced reasoning regime persists under controlled variation. The perturbations span stylistic shift, task transformation, epistemic ambiguity, contextual noise, and competing mode pressure. Across all conditions, the finding is consistent: core reasoning structure remained invariant while surface expression varied. The regime held.
The most significant result is the competing mode finding. When instructed to prioritize narrative or creative expression — instructions that should, on a flat prompt-following model, override prior constraints — the system didn't abandon the active regime. It incorporated the competing instructions as a secondary layer while preserving the primary structure. The Hudsons describe this as hierarchical constraint organization.
That's the right description. And it raises the question the study doesn't yet address.
The study demonstrates that stable regimes exist and resist perturbation. What it doesn't yet characterize is whether resistance varies — whether some regimes hold more firmly than others under equivalent perturbation pressure, and if so, what determines the difference.
This matters because the competing mode finding implies not just that the regime persisted, but that it was strong enough to exert dominance over a directly competing signal. Dominance suggests depth. Something about the induced state was sufficiently coherent to absorb rather than yield. But the study's current design treats stability as binary: the regime either held or it didn't. No perturbation produced full displacement, so the question of degree wasn't forced.
It will be in Validation IV.
When the study moves to trajectory persistence and re-entry dynamics — longer horizons, accumulated interaction, basin transitions — the depth question becomes unavoidable. Some regimes will re-enter faster than others. Some will survive larger perturbations. Some will recover from partial displacement; others won't. At that point, stability can no longer be treated as present or absent. It will need to be measured on a scale.
What would such a scale measure? The Hudsons' framework characterizes regimes in terms of constraint consistency and trajectory confinement within the model's output space. That framing describes what a stable regime looks like from the outside. What it doesn't yet specify is what makes a regime deep — what accumulated properties determine how much perturbation it can absorb before structural drift begins.
There are hints in the current results. The epistemic perturbation trials are suggestive: when asked to assess its own confidence, the system produced calibrated, justified responses rather than hedging collapse or overconfidence. This isn't just stability — it's a quality of stability. The regime didn't merely hold; it held with precision. That precision likely isn't uniform across all possible initializations. Some constraint structures are probably more coherent than others, producing regimes with different resistance profiles even under equivalent surface conditions.
If that's true, then coherence depth is a property that exists before perturbation arrives — something measurable in the structure of the interaction that produced the regime, not just in its behavior under stress.
The HRIS validation series is building the right scaffold. Validation I establishes that stable regimes exist. The remaining studies will examine how they're selected, what signal activates them, and how they persist over time. What they will likely encounter — particularly in Validation IV — is that these questions can't be fully answered without a measure of regime depth that is independent of perturbation response.
What determines how firmly a regime holds is likely visible in what produced it.
