Why do people do stupid things? In our recent book, *Game Theory and the Transformation of Family Law, *Attorney Allan Koritzinsky and I suggest a bargaining process founded on game theory. But why game theory? Game theory is a branch of mathematics that analyzes how and why people make the choices that they make. Although it had humble beginnings in the study of parlor games, the application of Game Theory has expanded to use in strategic war planning, economics and even a couple of branches of law, earning five game theorists Nobel Prizes. Recently, a couple of authors have included game theory in the study of marriage and divorce. We introduce game theory here because we are going to illustrate applications to family law in subsequent blog postings.

Natural selection favored humans that could make instantaneous calculations of what choices were most likely to have optimal outcomes. Although humans who survived and reproduced, made calculations on how hard, high and at what angle, taking into consideration the mass of an object and the effects of gravity, to throw a rock or spear at a moving animal, the formal branch of mathematics was not developed until Sir Isaac Newton invented calculus. Similarly, humans made choice calculations long before game theory was invented, but like calculus, game theory provides mathematical proofs. A game is defined by its parts: players, rules, choices and payoffs. In family law, the players are the divorcing spouses; the rules are law, local rules and legal culture; the choices are with regard to the legal outcomes (proposals and counter-proposals); and the payoffs are the benefits provided to the parties as a result of those outcomes.

Analyzing with game theory reveals the counterintuitive finding that the traditional family law system is a game best played with competitive, conflictual and dispute-oriented choices/strategies to reach substantially less than optimal outcomes. Anyone familiar with the *Prisoners’ Dilemma* will understand that a game can be set up so that rational people make self-defeating choices. In the next 10 blog postings, we will be analyzing, with game theory, the traditional family law system and revealing how it tricks people into making rational, but self-defeating choices. Professionals involved in traditional law intuitively know that there is something wrong with the way the system handles families in transition from intact marriage to separation. Game theory tells us what is wrong! Later blogs point in the direction of correction. Stay tuned!