A2 Distortion due to group influence

Topic

The starting point remains the individual, represented as a generalized actor who makes choices—regarding consumption, labor, savings, migration, childbearing, trust, or participation in collective action—based on a cost-benefit decision function applied to whatever choice set the context presents. This cost-benefit decision function relies on a vector of personal characteristics—preferences, available resources, identity, and risk tolerance—while resource constraints limit the individual to a specific subset of available options.

At least two components compete within this cost-benefit decision function: one based on private cost-benefit analysis (anchored to the individual's characteristics and resource constraints) and another based on social context. When the weight of the social context component surpasses that of the private cost-benefit component, the individual's decision shifts from being primarily anchored in their own private calculation to being governed by the social context. This represents a threshold crossing rather than a gradual shift: below the threshold, the individual decides largely for themselves, whereas crossing it transfers effective control over the decision to the social context component.

Reducing the individual's choice set to a single binary alternative—whether or not to join a collective action—causes the competition between the private cost-benefit component and the social context component to manifest as the classic threshold model attributed to Granovetter, rather than as a general decision function applied to a full choice set; it is the same threshold-crossing dynamic inherent in the competition between the two components, viewed in its simplest form. This threshold crossing is not confined to a single individual: when many "Level 0" actors—driven by this same distortion arising from group influence—cross the same shared threshold in a coordinated manner, six distinct population-level phenomena emerge. Each corresponds to one of the six channels of collective behavior that aggregate individual decisions: the misinformation cascade, the echo chamber, the stampede, groupthink, the cult of personality, and the collapse of generalized trust. In all six cases, the event occurring at the population level is essentially the same individual—crossing the same threshold between private cost-benefit analysis and social context, often simultaneously—multiplied across a shared context.

This is why this second pathway of distortion allows us to identify a common origin for six phenomena that might otherwise appear to be unrelated manifestations—the misinformation cascade, the echo chamber, the stampede, groupthink, the cult of personality, and the collapse of generalized trust—within any decision an individual makes (whether to consume, work, save, migrate, have children, trust, or join a collective action). All of them are explained by the same threshold crossing within the individual's decision-making process, repeated and coordinated across many actors within the same context.

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