Marco Mariotti: Self-Confirming Opportunity Costs

We study choice when alternatives are evaluated relative to endogenous opportunity costs. We propose the Self-Confirming Opportunity Model (SCOM), an intrapersonal equilibrium concept. In a SCOM each alternative is paired with the option chosen from the remaining menu as its opportunity cost, and choice maximises a menu-independent quaternary preference over such pairs. We provide a revealed-preference characterisation of this model. SCOM accommodates cyclical choice, Condorcet inconsistencies and choice overload patterns within a disciplined maximisation framework. Standard rational choice obtains if and only if the underlying quaternary preference satisfies a coherence condition, yielding a strict order over alternatives.