Game Theory.

Shared resources depend on both individual demand and the rules people build together.

A tempting individual move can leave both players worse off.

Who receives the upside—and who bears the loss—can change a decision.

A valuable shared goal can require confidence that others will join.

Each side wants the other to yield, but mutual escalation is costly.

A predictable choice can be exploited even when neither pure choice is best.

A shared convention can help people choose the same place without talking.

A contribution can benefit the whole group while costing the contributor.

An offer can be profitable and still be rejected.

A negotiated split depends on what each side can get without a deal.

Paying the second-highest bid changes the incentive to report your value.

The highest estimate may be the one with the largest upward error.

When buyers cannot observe quality, good products can leave the market.

People can follow earlier actions even when their own clue disagrees.

A shared project succeeds only after enough people contribute.

The first person can grow a shared pie but cannot force a fair return.

Passing grows the pot, but each player can take it first.

Everyone benefits if one person acts, but each hopes someone else will.

Try to predict what others will predict, not a number's intrinsic value.

Two sellers compete for customers spread along one street.

An extra shortcut can make selfish routing slower for everyone.

Moving toward the middle can win more nearby voters in a simple one-dimensional election.

If everyone expects a quiet venue, the venue may become crowded.

Spending more effort raises your chance of winning but everyone pays their effort cost.

When someone acts on your behalf, whose interests are they serving?