Game Theory Helps Explain Animal Behavior
Mathematics Aids the Understanding of Biological Processes
Jul 28, 2009
Game theory is a branch of applied mathematics originally developed to study certain patterns of human behavior. Game theory is an interdisciplinary enterprise employing facets of mathematics, economics, and other social and behavioral sciences.
Understanding Game Theory
For the most part, the field of game theory was established in 1944 in a classic book written by mathematician Jon von Neumann and mathematical economist Oskar Morgenstern entitled, Theory of Games and Economic Behavior.
Game theory is derived from neoclassical economics and both are based on the principle and assumption of individual rationality. That is, each person makes rational decisions that maximize their rewards – profits or other subjective benefits – within the circumstances they face.
Neoclassical economics imagines a rational individual facing a system of institutions – property rights, money, and highly competitive markets. From this perspective the individual need only concern themselves with their own situation and the “conditions of the market,” not with other individuals. However, this restricted view seriously limits the application of neoclassical economics, especially to matters outside the money economy.
Game theory was developed to address the shortcomings of neoclassical economics and provide a theory of economic and strategic behavior when people interact directly rather than “through the market.” Game theory is not about games but it is about serious human interactions where, as in games, an individual’s choice is a strategic choice whose outcome depends on the strategies chosen by others interacting directly with that individual.
In neoclassic economic theory, to choose rationally is to maximize one’s rewards. Game theory presents a much more complex (and realistic) approach since the outcome of a given situation depends not only on the strategic decisions made by an individual as well as the “market conditions,” but also directly on the strategic decisions made by other individuals. Game theory then is a mathematical problem in which one attempts to understand how the strategic rational choices made by a group of interacting decision makers maximizes the rewards of the group.
The Application of Game Theory to Biology
Game theory has proven to be of considerable use to evolutionary biologists, especially behaviorists. Whereas in economic game theory the end game is maximizing money, in biological game theory the outcome is fitness and survival. Game theory is useful in understanding situations where the fitness and survival of an individual and the consequence of that individual’s behavior depend in part on the types and frequencies of behaviors exhibited by other animals in a given population.
The study of raven behavior offers a biological case in point to the application of game theory to biological matters. Young ravens often scout for carrion alone but when they find it, they recruit other young ravens to join the feast. Biologists were puzzled as to how such apparent altruistic behavior can benefit the original scout raven.
Mathematical ecologist Sasha Dall of the University of Exeter in England used a game theory model to explain the behavior of the scout raven. Dall’s model indicates that the behavior of the scout raven is evolutionarily sensible because more young ravens on a carcass can help fight off territorial adults and also allows the scout raven to secure dominance over recruited ravens.
In another game theory model Dall predicted gang foraging in ravens in which a large number of birds scavenge together. However, at that point, such behavior in ravens had never been observed in the wild. Behavioral ecologist Jonathan Wright of the Norwegian University of Science and Technology soon verified Dall’s prediction by observing ravens gang foraging.
Miller verified his observations by implanting carcasses with different-colored beads. Ravens feeding on the same carcass would ingest and later cough up the same color beads. Analysis demonstrated that ravens in some groups (roosts) were searching and eating together, a benefit for the entire group. Dall and Miller merged their work in a paper entitled “Rich Pickings Near Communal Roosts Favour ‘Gang’ Foraging by Juvenile Common Ravens, Corvus croax” published February 25, 2009 in the journal PLoS One.
Game theory has also been used to analyze the evolutionary significance of 1:1 sex ratios and to explain the evolution and emergence of animal communication.
“Paradoxically, it has turned out that game theory is more readily applied to biology than to the field of economic behaviour for which it was originally designed.”
(Maynard Smith, in the preface to Evolution and the Theory of Games)
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