Abstract: (...) the prevalence of bias or handedness in one direction (Lateralisation) is likely to result from social selection pressures, rather than mere evolutionary chance or genetics. We have long known that the two sides of the brain perform different functions - the left hemisphere for language and the right for visual-spatial functions. One consequence of brain asymmetry is lateralisation - the preferential use of a limb or eye (...). Taking the example of predator/prey interactions, scientists have used the mathematical 'theory of games', to show that 'deciding' to have the same direction of asymmetry as other individuals in the group could be an advantage.