These notes review two simple heterogeneous agent models in economics and finance. The first is a cobweb model with rational versus naive agents introduced in Brock and Hommes (1997). The second is an asset pricing model with fundamentalists versus technical traders introduced in Brock and...

Interacting agents in finance represent a behavioral, agent-based approach in which financial markets are viewed as complex adaptive systems consisting of many boundedly rational agents interacting through simple heterogeneous investment strategies, constantly adapting their behavior in response...

We develop a simple agent-based financial market model in which heterogeneous speculators apply technical and fundamental analysis to trade in two different stock markets. Speculators' strategy/market selections are repeated at each time step and depend on predisposition effects, herding...

Using data on one-shot games, we investigate the assumption that players respond to underlying expectations about their opponent's behavior. In our laboratory experiments, subjects play a set of 14 two-person 3x3 games, and state first order beliefs about their opponent's behavior. The sets of...

We analyze differences in consumption and wealth that arise because of different degrees of rationality of households. In particular, we use a standard New Keynesian model and let a certain fraction of households be fully rational while the other fraction possesses less cognitive ability. We...

This essay links some of my own work on expectations, learning and bounded rationality to the inspiring ideas of Jean-Michel Grandmont. In particular, my work on consistent expectations and behavioral learning equilibria may be seen as formalizations of JMG's ideas of self-fulfilling mistakes....

We develop a model in which investors can participate in stock, bond and housing markets. Investors' market entry decisions are subject to herding effects and depend on the markets' price trends and on their mispricings. The dynamics of our model is governed by a four-dimensional nonlinear map...

We propose a heuristic switching model of an asset market where the agents' choice of heuristic is consistent with their individual risk aversion. They choose between a fundamentalist and a trend-following rule to form expectations about the price of a risky asset. Given their risk aversion,...

News reports and communication are inherently constrained by space, time, and attention. As a result, news sources often condition the decision of whether to share a piece of information on the similarity between the signal and the prior belief of the audience, which generates a sample selection...

This note evaluates how adaptive learning agents weigh different pieces of information when forming expectations with a recursive least squares algorithm. The analysis is based on a new and more general non-recursive representaion of the learning algorithm, namely, a penalized weighted least...