nep-evo New Economics Papers
on Evolutionary Economics
Issue of 2015‒03‒05
three papers chosen by
Matthew Baker
City University of New York

  1. Culture, Ethnicity and Diversity By Desmet, Klaus; Ortuño-Ortín, Ignacio; Wacziarg, Romain
  2. Choosing a Good Toolkit: An Essay in Behavioral Economics By Kreps, David M.; Francetich, Alejandro
  3. Diversity waves in collapse-driven population dynamics By Sergei Maslov; Kim Sneppen

  1. By: Desmet, Klaus; Ortuño-Ortín, Ignacio; Wacziarg, Romain
    Abstract: We investigate the empirical relationship between ethnicity and culture, defined as a vector of traits reflecting norms, attitudes and preferences. Using surveys of individual values in 76 countries, we find that ethnic identity is a significant predictor of cultural values, yet that within-group variation in culture trumps between-group variation. Thus, in contrast to a commonly held view, ethnic and cultural diversity are unrelated. We explore the correlates of cultural diversity and of the overlap between culture and ethnicity, finding that the level of economic development is positively associated with cultural diversity and negatively associated with the overlap between culture and ethnicity. Finally, although only a small portion of a country's overall cultural heterogeneity occurs between groups, this does not imply that cultural differences between groups are irrelevant. Indeed, we find that civil conflict becomes more likely when there is greater overlap between ethnicity and culture.
    Keywords: between-group diversity; civil conflict; cultural fractionalization; cultural traits; culture; ethnicity; heterogeneity; identity; social norms; within-group diversity
    JEL: D74 J15 P48 Z10
    Date: 2015–03
  2. By: Kreps, David M. (Stanford University); Francetich, Alejandro (?)
    Date: 2014–05
  3. By: Sergei Maslov; Kim Sneppen
    Abstract: Populations of species in ecosystems are constrained by the availability of resources within their environment. In effect this means that a growth of one population, needs to be balanced by the reduction in size of others. In neutral models of biodiversity all populations are assumed to change incrementally due to stochastic births and deaths of individuals. Here we propose and model another redistribution mechanism driven by abrupt collapses of the entire population of a single species freeing up resources for the remaining ones. This mechanism may be relevant for communities of bacteria, with strain-specific collapses caused e.g. by invading bacteriophages, or for other ecosystems where infectious diseases play an important role. The emergent property of the population dynamics in our system are cyclic "diversity waves" triggered by collapses of globally dominating populations. The population diversity in the environment peaks at the beginning of each wave and exponentially decreases afterwards. Population sizes in our system follow a bimodal distribution with the lower peak composed of the recently collapsed or the newly arrived species. In contrast to this, the upper peak of the distribution consists of the surviving species in the current diversity wave. The populations of the most abundant species in the upper peak exhibit a scale-free distribution with a nearly universal exponent of about 1.7. We show that our model is robust with respect to variations in dynamical rules including gradual redistribution of populations between subsequent collapses and variation in species' growth or collapse rates.
    Date: 2015–03

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