Self-referential processing as the biological switch between classical and quantum functioning of the brain.

Dual-process theory of the brain distinguishes fast, parallel, late-commitment cognition (System 1) from slow, sequential, early-commitment cognition (System 2), yet lacks a mechanistic explanation for how these modes operate or how the brain switches between them. Quantum cognition research demonstrates that human decision-making follows quantum probability models under low confidence and classical Markov models under high confidence, suggesting a hybrid architecture where decoherence drives transitions between processing modes. We propose that self-referential evaluative monitoring functions as the biological switch that regulates the transition between System 1 and System 2 by modulating microtubule-mediated quantum coherence through electromagnetic boundary conditions. The causal chain proceeds from locus coeruleus-norepinephrine regulation of default mode network (DMN) activity, through electromagnetic field patterns generated by self-evaluation, to calcium-mediated modulation of the microtubule electrostatic environment. Recent experimental evidence indicates that microtubules exhibit quantum exciton energy migration comparable to photosynthetic complexes, with cooperative robustness increasing with system size. Because quantum coherence enables parallel exploration while classical processing offers stability, evolution would have selected for mechanisms that balance these demands. Anesthetics bind promiscuously yet selectively abolish consciousness, which is consistent with disruption of energy-threshold-dependent coherent processes in microtubules. The framework proposed in this paper leads to testable predictions relating DMN activity, flow states, insight, and confidence to shifts along the quantum-classical processing spectrum.