title: Spectacular phenomena and limits to rationality in genetic and cultural evolution.
abstract: In studies of both animal and human behaviour, game theory is used as a tool for understanding strategies that appear in interactions between individuals. Game theory focuses on adaptive behaviour, which can be attained only at evolutionary equilibrium. We suggest that behaviour appearing during interactions is often outside the scope of such analysis. In many types of interaction, conflicts of interest exist between players, fuelling the evolution of manipulative strategies. Such strategies evolve out of equilibrium, commonly appearing as spectacular morphology or behaviour with obscure meaning, to which other players may react in non-adaptive, irrational ways. We present a simple model to show some limitations of the game-theory approach, and outline the conditions in which evolutionary equilibria cannot be maintained. Evidence from studies of biological interactions seems to support the view that behaviour is often not at equilibrium. This also appears to be the case for many human cultural traits, which have spread rapidly despite the fact that they have a negative influence on reproduction.
authors.affiliation: Department of Zoology, University of Stockholm, S-106 91 Stockholm, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Enquist
authors.forename: Anthony
authors.initials: A
authors.lastname: Arak
authors.forename: Stefano
authors.initials: S
authors.lastname: Ghirlanda
authors.forename: Carl-Adam
authors.initials: CA
authors.lastname: Wachtmeister
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D005075:Biological Evolution; D003220:Conflict, Psychological; D003469:Culture; D005716:Game Theory; D006801:Humans; D008954:Models, Biological; D012919:Social Behavior