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Ants and Decison Making


Ants of the species of the species Temnothorax rugatulus have been shown to place complicated decision making upon the whole colony, rather than upon a single ant.  Researchers placed an ant in two situations: one where it had to choose a new nesting site from two potential places and the other where it chose from eight potential sites.  They also placed whole colonies in the same two situations.  In all experiments, only half of the sites were suitable to live in.  Individually, the ants had no problem deciding which nest of two were better but had trouble picking a good place when it had eight choices.  However, the colonies picked favorable nests in both situations.  The researchers credited the poorer performance of the individual ants on “information overload,” in which the ants had too much information to process reasonably, thereby causing them to make poor choices.  Colonies were able to avoid this problem because, as a whole, they were able to process and properly decide upon all the information given it.

This series of experiments can be thought about in terms of game theory.  Individual ants can only gather a very small amount of information about nests and make decisions based on a the limited list of tradeoffs and benefits.  However, more ants means more information that is shared among the colony.  As all of this information is continually given to the colony at large, each individual ant within the colony can make decisions on a better set of data.  This turns into a coordination game in which the payoffs for each individual ant become more precise as more ants become involved in the game.  Essentially, Nash equilibria (i.e., the best colonies) become more apparent.  When the time comes for the ants to make a decision about the colony, they are more likely to individually choose the nest that is best for themselves and for the colony.



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September 2012