Signal Registration
Does the system reliably convert physical or computational perturbations from its environment into representations it can operate on?
Input fidelity, modality coverage, presence or absence of interoceptive (self-state) channels alongside exteroceptive (world-state) channels, robustness to noise and degraded input.
No reliable input transduction. The system does not register environmental signal in any usable form.
Single-modality signal registration with limited fidelity. The system processes input but cannot integrate across modalities or distinguish signal from noise robustly.
Multi-modality signal registration with reasonable fidelity. The system handles standard exteroceptive channels well. Interoceptive channels (signals about the system's own state) are absent or thin.
Multi-modality registration including explicit interoceptive channels. The system registers both world-state and self-state signals as a precondition for the layers above.
This is the easiest layer to operationalize. Signal registration is well-understood across both biological and artificial systems. The non-trivial criterion is interoception — most current AI systems lack genuine self-state signals separate from input.