AIM Framework glossary
Susceptibility-Dispersion Result
Canonical definition
Canonical Definition. The Susceptibility-Dispersion Result states that population heterogeneity acts on mimetic-cascade risk through two independent axes of opposite sign. The content axis — the number of distinct hypotheses a population entertains — is protective and operates through the corrective rate (the Belief Heterogeneity Buffer). The susceptibility axis — the dispersion of adoption thresholds across Individuals, where an Individual's threshold is the amount of social evidence required before they adopt a circulating hypothesis — is anti-protective and operates through vanguard recruitment: a dispersed threshold distribution guarantees a low-threshold tail that adopts first on minimal evidence, and because expressed Belief is itself social proof, each conversion raises the effective pressure on the next layer, so that greater dispersion lowers the external drive required to ignite the whole population even at fixed mean threshold and fixed content heterogeneity. The two axes couple as a ratchet, because an igniting cascade converts adherents off their prior hypotheses and thereby drains content heterogeneity as it spreads; hence the Belief Heterogeneity Buffer is necessary but not sufficient. In AIM the adoption threshold is not primitive but is set by the Individual's Mimetic weighting, effective Coupling Strength, Appetite state (via the fidelity channel of the Upstream Corruption Principle), and believed own standing, which enters through the grievance channel by which Appetite deficit raises amplification: an Individual whose believed standing exceeds their provisioning holds a prior under which grievance-consistent Hypotheses carry higher likelihood, so less social evidence suffices to carry them. Sustained deprivation therefore manufactures a low-threshold vanguard, and because the Self-Standing Confirmation Principle drives believed standing apart in both directions within a single deprived segment, it disperses thresholds on the anti-protective axis rather than merely lowering their mean — the distributional mechanism of the Floor-Breach Ignition Corollary (Appendix A, A.5.8.7; Chapter 13, §13.7.4). The result recovers, and supplies a motivational microfoundation for, the threshold-and-contagion tradition of Granovetter (1978), Watts (2002), and Centola and Macy (2007). Framework-Specific Named Result.
Explanation
There are two different kinds of "variety" in a population and they pull in opposite directions. Variety in what people believe — many groups blaming many different enemies — is protective, because the competing stories cancel out. Variety in how easily people are swayed — some who will believe anything on a whisper, some who need a stampede — is dangerous, because the easily-swayed few tip first, and once they visibly tip they become the pressure that tips the next-easiest, and so on, a chain reaction a uniform population never starts. The two interact: as the chain reaction spreads it destroys the belief-variety that was the other protection. So a diversity of opinions is necessary but not enough. And because hardship is what makes people easy to sway, deprivation manufactures the easily-tipped vanguard that lights the fire — which is what "going viral" describes, given a precise cause.
Epistemic status
Framework-Specific Named Result.
Derivation
Chapter 13, Section 13.8; formal statement at Appendix A, Section A.5.8.7.