A model of decentralized trade is simulated with firms that produce a given commodity, and consumers who repeatedly wish to purchase on unit of that commodity. Consumers ``shop around,'' while firms may attract the attention of potential customers by sending information signals and offering good...

Genetic algorithms are computational models of evolution that play a central role in many artificial life models. We review the history and current scope of research on genetic algorithms in artificial life, using illustrative examples in which the genetic algorithms is used to study how...

Randomly connected networks of Boolean logic functions of fixed in-degree ("Kauffman Nets") are analyzed using an annealed approximation. While these nets originated as models of genetic regulatory networks, the conclusions and observations obtained by treating them as a complex type of spin...

Rationality is a complex behavioral theory that can be parsed into statements about preferences, perceptions, and process. This paper looks at the evidence on rationality that is provided by behavioral experiments, and argues that most cognitive anomalies operate through errors in perception...

We study the nature and mechanisms of broken ergodicity (BE) in specific random walk models corresponding to diffusion on random potential surfaces, in both one and high dimension. Using both rigorous results and nonrigorous methods, we confirm several aspects of the standard BE picture and show...

We analyze economic efficiency and equilibrium properties in decentralized task allocation problems involving hierarchical dependencies and resource contention. We bound the inefficiency of a type of approximate equilibrium in proportion to the number of agents and the bidding parameters in a...

During the period of approximately 1570--1790 the first metamorphosis of science transformed the operational foundations of science, that were largely the heritage from the time of Aristotle, into its modern form. These new foundations consisted of the use of (1) Physical Experiments and the use...

This paper describes a range of methods which have been proposed to study interactions in economic and social contexts. By interactionsk, we refer to interdependences between individual decisions which are not mediated by markets. These types of models have been employed to understand phenonmena...

Large variations in stock prices happen with sufficient frequency to raise doubts about existing models, which all fail to account for non-Gaussian statistics. We construct simple models of a stock market, and argue that the large variations may be due to a crowd effect, where agents imitate...

We present empirical evidence that long-term evolutionary dynamics fall into three distinct classes, depending on whether adaptive evolutionary activity is absent (class 1), bounded (class 2), or unbounded (class 3). These classes are defined using three statistics: diversity, new evolutionary...