An information cascade occurs when individuals adopt a new behavior based on the signals and actions of individuals surrounding them. We can also treat this propagation of a new behavior throughout a network as games played between individuals in which the superior strategy is “passed down” to individuals in the “outer levels” of the network. In biology this idea is known as natural selection and sometimes as “survival of the fittest”. Crediting the biological origin of this idea, this branch of game theory is called evolutionary game theory and is more concerned with how a new behavior possessed by a minority may affect the whole population.

In “Survival of the Clearest”, Steven Pinker talks about evolutionary linguistics and how evolutionary game theory models defining properties of human languages. In the evolutionary game theory paradigm the “behavior” that is propagating through the network is a particular type of language. In the model, we assume that a better language enabled our human ancestors to survive longer and allowed them to produce offspring that inherited these communication skills as well. James Hurford used evolutionary game theory to show that arbitrary bidirectional sign is evolutionary stable in 1989. Arbitrary bidirectional sign describes a community in which they implicitly agree on certain signals to refer to particular concepts.

One of the problems with this scheme is that there are more concepts in the world than the number of unique sounds humans can produce for each one. At some point it will become difficult to distinguish the sounds correctly, and impede communication instead of facilitating it. In 1999 Nowak and Krakauer showed that organisms never transmit information perfectly partly for this reason. They showed one way to overcome the limitation is to limit the number of sounds, but string individual sounds together to express different concepts, which we call words. With so many words it’s highly unlikely that all of them will “survive” unless people continue to use them. Nowak et al showed that this wasn’t a limitation if people related words to components of an event (e.g. from article is dog bites man), thus gradually the language develops syntax and semantics. Although this is a model of how language may have evolved, Pinker points out that game theorists continue to show evolving nature of many special features of language such as arbitrary signs and duality of patterning. As more abstract elements of language including lexicon, phonology, syntax, and semantics are shown to be the result of physical limitations some suggest that the evolution of language is closely related to human evolution.