Friday, July 10, 2009

Evolution Guides Cooperative Turn-Taking, Game Theory-Based Computer Simulations Show

ScienceDaily -- It's not just good manners to wait your turn -- it's actually down to evolution, according to new research by University of Leicester psychologists.

A study in the University's School of Psychology sought to explain how turn-taking has evolved across a range of species. The conclusion is that there is an evolution-based "invisible hand" that guides our actions in this respect. What's more, the researchers have shown that this behavior can be simulated using a simple computer algorithm and basic genetic laws.

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The researchers say that playing "tit for tat" -- copying in each time period whatever the other individual did in the previous period ­-- can explain synchronized cooperation, but cannot fully explain turn-taking. "For example, many predatory animals hunt in pairs or larger groups, and this involves synchronized cooperation. 'Tit for tat' has been shown to work very well in initiating and sustaining this type of cooperation."

"But where cooperation involves turn-taking, a 'tit for tat' instinct could sustain the pattern once it was established but could not initiate it in the first place. For example, in a mating pair of penguins who both went foraging or both incubated the eggs at the same time, 'tit for tat' would not be enough to evolve the habit of taking turns."

Using evolutionary game theory and computer simulations, Professor Colman and Dr Browning discovered a simple variation of "tit for tat" that explains how turn-taking can evolve in organisms that pursue their individual self-interests robotically.

The researchers state: "Turn-taking is initiated only after a species has evolved at least two genetically different types that behave differently in initial, uncoordinated interactions with others. Then as soon as a pair coordinates by chance, they instinctively begin to play 'tit for tat'. This locks them into mutually beneficial coordinated turn-taking indefinitely. Without genetic diversity, turn-taking cannot evolve in this simple way."

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