Game theory studies strategic decision-making — situations where your optimal choice depends on what others choose. The central insight: people respond to incentive structures, not stated intentions. If you want to predict behavior, don't ask what people SAY they'll do — look at what the incentive structure rewards.

The Prisoner's Dilemma illustrates the core tension: two prisoners can cooperate (stay silent) or defect (betray the other). If both cooperate, both get light sentences. If both defect, both get harsh sentences. But if one defects while the other cooperates, the defector goes free. The rational individual strategy (defect) produces a worse collective outcome than cooperation. This structure appears everywhere: arms races, climate negotiations, market competition, and social dilemmas.

Misaligned incentives explain most institutional failures. Doctors paid per procedure perform more procedures. Lawyers paid by the hour take longer. Financial advisors paid by commission recommend products that generate commissions. Teachers measured by test scores teach to the test. In each case, the individual is responding rationally to their incentive structure — the problem is the structure, not the person.

Once you understand incentive structures, you see them everywhere — and your ability to navigate institutions transforms.

Moral hazard: when one party takes risks because another party bears the costs. Banks took excessive risks before 2008 because they expected government bailouts — the profits were private, the losses were public.

Principal-agent problem: when someone (agent) makes decisions on behalf of another (principal) but their interests diverge. Your financial advisor (agent) may recommend products that maximize their commission rather than your returns (principal). Align incentives by choosing fee-only advisors.

The practical application: for any institution, ask: "What behavior does the incentive structure reward?" If it rewards something different from what the institution claims to value, trust the incentives. Hospitals claim to value health; fee-for-service rewards treatment volume. Universities claim to value learning; publish-or-perish rewards research output. Platforms claim to value connection; engagement metrics reward outrage. The gap between stated values and structural incentives is where manipulation lives.