When each player in a population game continuously adjusts her action to move up the payoff gradient, then the state variable (the action distribution) obeys a nonlinear partial differential equation. We find conditions that render gradient adjustment myopically optimal and analyze two broad...

Several impatient investors with private costs <em>C_i</em> face an indivisible irreversible investment opportunity whose value <em>V</em> is governed by geometric Brownian motion. The first investor <em>i</em> to seize the opportunity receives the entire payoff, <em>V-C_i</em>. We characterize the symmetric Bayesian Nash...

Any absolutely continuous, piecewise smooth, symmetric two-player game can be extended to define a population game in which each player interacts with a large representative subset of the entire population. Assuming that players respond to the payoff gradient over a continuous action space, we...

An irreversible investment opportunity has value V governed by Brownian motion with upward drift and random expiration. Human subjects choose in continuous time when to invest. If she invests before expiration, the subject receives V−C : the final value V less a given avoidable cost C ....

Fund managers respond to the payoff gradient by continuously adjusting leverage in our analytic and simulation models. The base model has a stable equilibrium with classic properties. However, bubbles and crashes occur in extended models incorporating an endogenous market risk premium based on...

Human players in our laboratory experiment converge closely to the symmetric mixed Nash equilibrium when matched in a single population version of the standard Hawk-Dove game. When matched across two populations, the same players show clear movement towards an asymmetric (and very inequitable)...

We report laboratory experiments that use new, visually oriented software to explore the dynamics of 3x3 games with intransitive best responses. Each moment, each player is matched against the entire population, here 8 human subjects. A "heat map" offers instantaneous feedback on current profit...