Significance of diadematid echinoid ossicles in micropalaeontological samples,Miocene–Pliocene of Indonesia

Fragments of diadematoid echinoids from the early and middle Miocene, and late Miocene–Pliocene, respectively, of Java, Kalimantan and Sulawesi, Indonesia, are identified as diadematid spp. indet. (radioles from all sites) and Centrostephanus sp. (an interambulacral plate; early Miocene, Java). The radioles are probably a mixture of Diadema ± Centrostephanus ± Echinothrix. This is the first report of identifiable fossil diadematoid remains from Indonesia and demonstrates that these echinoids, so common in modern reef environments, were present in the Neogene of the region. Even though classified in open nomenclature, Centrostephanus sp. nevertheless provides further evidence for the Cenozoic record of a genus in which the only nominal species are of Late Cretaceous and Holocene age.     

BAYESIAN MODEL AVERAGING IN THE CONTEXT OF SPATIAL HEDONIC PRICING: AN APPLICATION TO FARMLAND VALUES

ABSTRACT Specification uncertainty arises in spatial hedonic pricing models because economic theory provides no guide in choosing the spatial weighting matrix and explanatory variables. Our objective in this paper is to investigate whether we can resolve uncertainty in the application of a spatial hedonic pricing model. We employ Bayesian Model Averaging in combination with Markov Chain, Monte Carlo Model Composition. The proposed methodology provides inclusion probabilities for explanatory variables and weighting matrices. These probabilities provide a clear indication of which explanatory variables and weighting matrices are most relevant, but they are case specific.     

Toy Story: Homophily,Transmission and the Use of Simple Simulation Models for Assessing Variability in the Archaeological Record

The interpretation of spatial and temporal patterns in the archaeological record remains a long-standing issue in the discipline. Amongst many methods and interpretations, modelling of ‘biased transmission’ has proved a successful strategy to tackle this problem. Here, we investigate a type of biased transmission, homophily, that is the tendency of individuals to associate and bond with similar others. In contrast to other social sciences, homophily remains underused in archaeology. In order to fill this gap, we develop six distinct variants of a well-established modelling framework borrowed from social science, Axelrod’s Cultural Dissemination Model. These so-called toy models are abstract models used for theory-building and aim at exploring the interplay between homophily and various factors (e.g. addition of spatial features such as mountains and coastlines, diffusion of innovations and population spread). The relevance and implications of each ‘toy model’ for archaeological reasoning are then discussed.