Abstract
Filial imprinting in precocial birds provides an unusually tractable example of how a brief early-life experience becomes a durable behavioral commitment. Decades of work in the domestic chick have identified the intermediate medial mesopallium (IMM), thyroid-hormone-dependent regulation of the sensitive period, rapid kinase and translational signaling, receptor and synaptic remodeling, later transcriptional divergence, and distributed retrieval networks. What remains unresolved is how these events relate across scales. Here the ARCH × Φ framework is extended into a recursively coupled execution-encoding architecture. At the execution layer, orienting and approach require the joint action of neural architecture (A), behavioral drive (D), stimulus context (C), and an immediate permissive state (Φ). At the encoding layer, activity generated by successful execution engages intracellular mechanisms that can reconfigure a multidimensional neural substrate. The resulting substrate change, rather than persistence of the original gate, alters future execution and learning capacity. In the chick, the sensitive-period component of Φ is treated operationally as an effective writability state with experimentally separable control points, including rapid thyroid-hormone signaling, GABAergic balance, and AKT/mTORC1-dependent translational capacity. This formulation explicitly accommodates evidence that the rapid imprinting-permissive action of T3 is non-genomic. Chromatin regulation is retained only as a plausible downstream stabilization mechanism whose direct role in chick IMM remains untested. The account further distinguishes the transient gate from the persistent substrate written while that gate is open, reinterprets priming as persistence of that substrate rather than prolonged T3 signaling, and represents encoding as signed, multidimensional reconfiguration rather than monotonic accumulation. The model generates testable predictions concerning gate control, modality-specific implementation, structural reorganization, cross-scale covariance, and retrieval-network redistribution. Filial imprinting is thereby treated as a special case of a broader biological problem: how transient permissiveness allows experience to rewrite the substrate on which future behavior is executed.