title: Coevolution of intelligence, behavioral repertoire, and lifespan.
abstract: Across many taxa, intriguing positive correlations exist between intelligence (measured by proxy as encephalization), behavioral repertoire size, and lifespan. Here we argue, through a simple theoretical model, that such correlations arise from selection pressures for efficient learning of behavior sequences. We define intelligence operationally as the ability to disregard unrewarding behavior sequences, without trying them out, in the search for rewarding sequences. We show that increasing a species' behavioral repertoire increases the number of rewarding behavior sequences that can be performed, but also the time required to learn such sequences. This trade-off results in an optimal repertoire size that decreases rapidly with increasing sequence length. Behavioral repertoire size can be increased by increasing intelligence or lengthening the lifespan, giving rise to the observed correlations between these traits.
authors.affiliation: Department of Psychology, Brooklyn College, 2900 Bedford Ave., Brooklyn, NY 11210, USA; Center for the Study of Cultural Evolution, Stockholm University, Lilla frescativ. 7B, S-106 91, Stockholm, Sweden. Electronic address: drghirlanda@gmail.com.
authors.forename: Stefano
authors.initials: S
authors.lastname: Ghirlanda
authors.affiliation: Center for the Study of Cultural Evolution, Stockholm University, Lilla frescativ. 7B, S-106 91, Stockholm, Sweden; Department of Zoology, Stockholm University, Svante Arrheniusv. 14D, S-106 91, Stockholm, Sweden. Electronic address: magnus.enquist@intercult.su.se.
authors.forename: Magnus
authors.initials: M
authors.lastname: Enquist
authors.affiliation: Center for the Study of Cultural Evolution, Stockholm University, Lilla frescativ. 7B, S-106 91, Stockholm, Sweden; Department of Zoology, Stockholm University, Svante Arrheniusv. 14D, S-106 91, Stockholm, Sweden. Electronic address: johan.lind@zoologi.su.se.
authors.forename: Johan
authors.initials: J
authors.lastname: Lind
mesh_terms: D001519:Behavior; D005075:Biological Evolution; D006801:Humans; D007360:Intelligence; D008017:Life Expectancy; D008962:Models, Theoretical
keywords: Evolution of behavioral repertoire; Evolution of intelligence; Evolution of lifespan; Mathematical model