Unified Theory of Ideological Contagion (The Somatic-Cognitive Parasite); Mapping Ideological Extremism as a Universally Contagious Neurobiological Pathology

Traditional sociopolitical frameworks consistently fail to explain the cross-ideological mechanics of radicalisation, relying on superficial analyses of semantic doctrine, socio-economic status, or educational attainment. This paper presents a multidisciplinary paradigm shift: the Unified Theory of Ideological Contagion. By establishing a rigid ontological separation between ideological software scripts (the variable content of specific dogmas) and neurobiological hardware (the central and autonomic nervous systems), we demonstrate that extremism is a universal, contagious somatic-cognitive pathology. Utilizing empirical functional neuroimaging (fMRI) data, we map the structural symmetry of extreme political polarities under a singular neuro-signature characterized by prefrontal-striatal degradation, metacognitive failure, and an algorithmic narrowing of cognitive flexibility along a predictable inverted-U curve. Somatically, we trace the infection trajectory through trauma-induced allostatic load and acute personal loss, which precipitate catastrophic vagal brake failure. This autonomic downshift forces a primitive evolutionary regression into a hyper-vigilant, threat-based survival loop, leaving the organism hyper-susceptible to neuro-cognitive transmission via interbrain synchrony and hyperscanning-verified neural coupling. Most critically, this paper identifies an original, systemic sensory deficit inherent to the active pathology: the decency blind spot. To permit outward, dehumanized violence, the host's nervous system must systematically attenuate mirror neuron networks and the broader social engagement system. This biological desensitisation strips the host of the neurocognitive architecture required to accurately decode universal, pro-social cues. While internal cell cohesion is maintained via highly localized, parochial in-group code-switching, the host remains biologically blind to the genuine human decency of external actors, explaining why pathologically possessed extremist networks exhibit a systemic vulnerability to undercover infiltration. Ultimately, we re-orient global counter-extremism strategies away from semantic debates, proving that effective intervention requires targeted physiological somatic regulation, heart rate variability restoration, and the deliberate rebuilding of individual neuro-cognitive flexibility.