116 research outputs found
Effective population and phenotype-genotype decoupling in cultural evolution
Although the attempt of sociobiology to provide a unified account of human biological and cultural evolution foundered on the sheer plasticity of human behaviour, subsequent attempts to rescue the relevance of evolutionary biology for the study of cultural phenomena have proved fruitful. A—perhaps the—major driver of this success has been the development of dual inheritance models (Boyd and Richerson 1985) that explicitly acknowledge the operation of both genetic and non- genetic inheritance in human sociocultural evolution. The development of such models has come about through, on the one hand, a willingness to apply Darwinian “population thinking” to social and cultural phenomena and, on the other, the recognition that biological genetic evolution is but one specific example of a more general ‘algorithm’ applicable to several domain beyond biology (Hull, 1982; Dennett, 1995).
Nevertheless, there remains considerable debate about whether cultural change is an evolutionary process operating on the same kinds of functional entities (replicators, interactors and lineages), or whether it is simply an analogous process. A common refrain in the debate about the status of cultural change as an evolutionary process, voiced by biologists and social scientists (Gould, 1987), is that if cultural change is evolutionary then it is Lamarckian rather that Darwinian. None of the protagonists believe that cultural evolution is literally Lamarckian in the sense that acquired cultural characteristics might somehow become encoded in genetic material. Rather, the question arises out of uncertainty surrounding what is genotypic and what is phenotypic in purely cultural evolution (e.g. Lake 1998). Indeed, in the case of the evolution of material culture, objects are often conceived as phenotypic expressions of genotypic ideas, but there may well be circumstances in which they actually function as cultural genotypes or even conflate both functions (Lake 1998).
Although the genotype-phenotype distinction in material culture is philosophically interesting, the question we address in this paper is essentially pragmatic: does the uncertainty surrounding the physical permanence of material culture actually matter for the application of models derived from evolutionary biology? We seek to explore potential implications of this phenomena for the application of one particular model that has been widely adopted for the study of cultural evolution:the neutral allele theory (Kimura, 1983). Originally developed in population genetics, its flexible and broad mathematical basis can serve as a null model for a variety of applications, including circumstances where the frequency of cultural variants change as a function of innovation rate and unbiased copying processes. The latter implies that variants are
replicated without any particular selective pressure, and random events associated with sampling errors can lead to the spread or loss of knowledge.
Archaeological applications of this null hypothesis produced a variety of results. Some exhibit empirical patterns predicted by the neutral model (e.g. Bentley et al. 2004), while others suggest the effect of systematic social choices or biases (e.g. Shennan and Wilkinson 2001). Premo (2014) has however demonstrated that techniques developed to identify neutrality are not necessarily capable of identifying unbiased cultural transmission in samples collected from time-averaged archaeological assemblages.
In this paper we argue that there is potentially another problem with using the standard biological neutral model to detect the emergence of systematic preferences in the evolution of material culture, i.e the possibility that the effective population of cultural models is the number of artefacts in circulation rather than the number of people producing them. In addition, considering the differential durability of material culture, it is also possible that this number includes artefacts created by previous generations of producers. The first issue was noted by Shennan and Wilkinson (2001). As we are aware there have been explorations of the concept of memory in language evolution (Bentley et al. 2011), but there are no formal studies concerning the consequences of the persistence of material culture on the application of the neutral model.
In order to investigate this problem we develop a simulation model where standard unbiased cultural transmission has been modified to incorporate a ‘production’ and a ‘persistence’ bias. Rather than formalising knowledge transfer as an individual-to- individual process, we build a model where individuals update their ‘genotype’ by copying from objects produced by other agents. This slight change in the model introduces two new mechanisms: the expression of the phenotype might be affected by stochastic events (‘production bias’), and objects might persist in the physical world for a given amount of time, potentially outliving their creator/genotype (‘persistence bias’). We generate a series of artificial archaeological records to examine whether these two biases modify the result of tests commonly used to detect neutrality in cultural datasets (Slatkin’s Exact test and Ewens-Watterson homozygosity test). Preliminary results suggest that this is the case, with the frequency of cultural variants showing significantly greater diversity than expected according to the standard neutral model. Our result thus indicates that in the presence of production and persistence bias there is a higher chance of incorrectly rejecting the null hypothesis of random copying/neutral cultural transmission
Wadi Halfayin e l'Oasi di Zukayt / Wadi Halfayin and the Oasis of Zukayt
Attivit\ue0:The Oasis of Zukayt & Wadi Halfayin Survey Project
Localit\ue0:Wadi Halfayin (ad-D\u101khilyyah)
Istituzione italiana:Universit\ue0 di Bologna
Partner istituzionale omanita:Ministry of Heritage and Culture
Partner istituzionali italiani/stranieri:The Institute of Archaeology, UCL
Responsabile italiano:Dott. Eugenio Bortolini, Universit\ue0 di Bologna
Stagioni di svolgimento:2008-2012
Testo di:Dott. Eugenio Bortolini, Universit\ue0 di Bologn
Quantifying the relationship between food sharing practices and socio-ecological variables in small-scale societies: A cross-cultural multi-methodological approach
This article presents a cross-cultural study of the relationship among the subsistence strategies, the environmental setting and the food sharing practices of 22 modern small-scale societies located in America (n = 18) and Siberia (n = 4). Ecological, geographical and economic variables of these societies were extracted from specialized literature and the publicly available D-PLACE database. The approach proposed comprises a variety of quantitative methods, ranging from exploratory techniques aimed at capturing relationships of any type between variables, to network theory and supervised-learning predictive modelling. Results provided by all techniques consistently show that the differences observed in food sharing practices across the sampled populations cannot be explained just by the differential distribution of ecological, geographical and economic variables. Food sharing has to be interpreted as a more complex cultural phenomenon, whose variation over time and space cannot be ascribed only to local adaptation.Spanish Ministry of Science, Innovation and Universities: SimulPast Project (CSD2010-00034 CONSOLIDER-INGENIO 2010), (VA, JC, EB, DZ, MM, JMG), Consolider Excellence Network (HAR2017-90883-REDC) (VA, JC, EB, DZ, MM, JMG), and CULM Project (HAR2016-77672-P)(DZ, JC, MM)
Sawmark Analysis of Three Cases of Amputation and a Craniotomy from the Seventeenth and Eighteenth Centuries Hospital Necropolis of Forlì Campus (Forlì, Italy)
The seventeenth-eighteenth century hospital necropolis of Forlì Campus (Forlì, Italy) was discovered during the Forlì Campus building work in 2014. Three cases of limb amputation and a craniotomy are examined using the forensic approach of sawmark analysis in order to understand features of the surgical instruments employed and to gain insight into the position of the surgeon during the cutting actions. With the aid of high definition photographs and moulds, we analyzed the cut surfaces of each sample, also using stereomicroscopy and SEM (Scanning Electron Microscopy). A qualitative and quantitative approach was used in the analysis of the kerf features (e.g. breakaway spur and notch, tooth scratches and hop, exit chipping), and empirical evidence was compared against comparisons coeval surgical essays. We hypothesize that a linear hand-powered push saw and an alternated push saw with a 2mm distance between the teeth were used for amputations. The craniotomy was executed presumably using a linear hand-powered saw with the set of the blade circa 1.3mm wide.
Through the application of forensic methods on individuals from archaeological context we describe early cases of surgical practice in a more technical way
Síntese e Caracterização de Óxido de Zinco Nanoparticulado: Preparo Via Método Sol-Gel e Aplicação como Catalisador na Degradação de Cloridrato de Ciprofloxacino
The present work reports the synthesis by the sol-gel method of nanoparticulate ZnO (nZnO) and evaluates its activity against commercial ZnO (cZnO) as a photocatalyst in the degradation of the antibiotic ciprofloxacin hydrochloride (CIP) in aqueous solution. The characterization of the nZnO was performed by DRX, MEV, MET and FTIR. The photodegradation experiments were organized according to 23 experimental design and the influence of the parameters [ZnO], [H2O2] and pH were evaluated statistically. The experimental results showed that the best conditions for the photodegradation process, [H2O2] = 500 mg L-1 and [ZnO] = 20 mg L-1 at pH 4, were identical for both photocatalysts, and nZnO activity was 6% higher than cZnO activity. The small difference observed in the activity of nZnO relative to cZnO can be attributed to the morphological heterogeneity of the nZnO obtained synthetically.O presente trabalho reporta a síntese pelo método sol-gel de ZnO nanoparticulado (nZnO) e avalia sua atividade frente ao ZnO comercial (cZnO) como fotocatalisador na degradação do antibiótico cloridrato de ciprofloxacino (CIP) em solução aquosa. A caracterização do nZnO foi realizada por DRX, MEV, MET e infravermelho com transformada de Fourier. Os experimentos de fotodegradação foram organizados em um planejamento experimental 23 e a influência dos parâmetros [ZnO], [H2O2] e pH foram avaliados estatisticamente. Os resultados experimentais mostraram que as melhores condições para o processo de fotodegradação, [H2O2] = 500 mg L-1 e [ZnO] = 20 mg L-1 em pH 4, foram idênticas para ambos fotocatlisadores, e a atividade do nZnO foi 6% superior à atividade do cZnO. A pequena diferença observada na atividade do nZnO em relação ao cZnO pode ser atribuída à heterogeneidade morfológica do nZnO obtido sinteticamente
Becoming adults: Exploring the late ontogeny of the human talus
Introduction: The talus plays an important role in receiving and dissipating the forces and linking the leg and the foot. As such, it is of paramount importance to analyze how its morphology, internal and external, changes during late ontogeny and through adolescence.
Method: To explore both the external shape and the internal architecture of the talus, Geometric Morphometrics and trabecular analysis have been applied to a sample of 35 tali from modern human juveniles aged between 5 and 15 years old (Middle Neolithic (4800-4500 BCE) to mid-20th century).
Results: Results show that, as the overall size of the talus increases, the shape and orientation of talar facets also change. The youngest individuals exhibit a functional talus that is still characterized by a relatively immature shape (e.g., subtly expressed margins of articular surfaces) with articular facets only minimally rotated towards an adult configuration. In adolescents, talar shape has achieved adult form after the age of 11, with all the articular facets and posterior processes well-developed. Considering internal morphology, trabecular bone varies between age classes. While Bone Volume Fraction shifts during the age 5-15 range, Degree of Anisotropy is relatively more stable over the developmental period examined in the study since it exhibits smaller variations between age classes.
Discussion: This study examined the late ontogeny of the human talus by considering both internal and external morphology. Results suggest that, although the locomotion has already assumed an adult-like pattern, the exploration of late talar growth may help understand how the talus adapts to changes in locomotor activity and how it responds to the increase in weight. Present results can be used to a better understanding of talar plasticity, improving interpretations of adult human talar form
New insights on Celtic migration in Hungary and Italy through the analysis of non-metric dental traits
The Iron Age is characterized by an extended interweaving of movements by Celts in Europe. Several waves of Celts from Western and Central Europe migrated southeast and west from the core area of the La Téne culture (between Bourgogne and Bohemia). Through the analysis of non-metric dental traits, this work aims to understand the biological relationship among Celtic groups arrived in Italy and the Carpathian Basin, as well as between local populations and Celtic newcomers. A total of 10 non-metric dental traits were analyzed to evaluate biological affinities among Celts (Sopron-Krautacker and Pilismarót-Basaharc) and Scythians-related populations from Hungary (Tápiószele), Celts from continental Europe (Switzerland and Austria), two Iron Age Etruscan-Celtic sites from northern Italy (Monterenzio Vecchio and Monte Bibele), 13 Iron Age central-southern Italic necropolises, and the northern Italian Bronze Age necropolis of Scalvinetto. Strontium isotopes were measured on individuals from the necropolis of Monte Bibele to infer their local or non-local origin. Results highlight the existence of statistically significant differences between Celts and autochthonous Italian groups. Celtic groups from Hungary and Italy (i.e., non-local individuals of Monterenzio Vecchio and Monte Bibele) share a similar biological background, supporting the historical records mentioning a common origin for Celts migrated to the eastern and southern borders of today’s Europe. The presence of a supposed Steppean ancestry both in Celts from Hungary and Celts from northern Italy corroborates the hypothesis of the existence of a westward migration of individuals and genes from the Steppe towards northern Italy during the Bronze and Iron Age, which contributed to the biological variability of pre-Celtic and later Celtic populations, respectively. Conversely, individuals from central-southern Italy show an autochthonous pre-Iron Age background. Lastly, this work supports the existence of Celtic migratory routes in northern Italy, as shown by biological and cultural admixture between Celts and Italics living together.E.P. was funded from the Erasmus+ Traineeship Program/KA103, Agreement n. 2020-1-IT02-KA103-078332. T.H. and K.G. were supported by the Hungarian Scientific Research Fund (FK128013), the Bolyai Scholarship granted by the Hungarian Academy of Sciences and the ÚNKP-22-5 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
An overview of Alpine and Mediterranean palaeogeography, terrestrial ecosystems and climate history during MIS 3 with focus on the Middle to Upper Palaeolithic transition
This paper summarizes the current state of knowledge about the millennial scale climate variability characterizing Marine Isotope Stage 3 (MIS 3) in S-Europe and the Mediterranean area and its effects on terrestrial ecosystems. The sequence of Dansgaard-Oeschger events, as recorded by Greenland ice cores and recognizable in isotope profiles from speleothems and high-resolution palaeoecological records, led to dramatic variations in glacier extent and sea level configuration with major impacts on the physiography and vegetation patterns, both latitudinally and altitudinally. The recurrent succession of (open) woodlands, including temperate taxa, and grasslands with xerophytic elements, have been tentatively correlated to GIs in Greenland ice cores. Concerning colder phases, the Greenland Stadials (GSs) related to Heinrich events (HEs) appear to have a more pronounced effect than other GSs on woodland withdrawal and xerophytes expansion. Notably, GS 9-HE4 phase corresponds to the most severe reduction of tree cover in a number of Mediterranean records. On a long-term scale, a reduction/opening of forests throughout MIS 3 started from Greenland Interstadials (GIs) 14/13 (ca. 55\u201348 ka), which show a maximum in woodland density. At that time, natural environments were favourable for Anatomically Modern Humans (AMHs) to migrate from Africa into Europe as documented by industries associated with modern hominin remains in the Levant. Afterwards, a variety of early Upper Palaeolithic cultures emerged (e.g., Uluzzian and Proto-Aurignacian). In this chronostratigraphic framework, attention is paid to the Campanian Ignimbrite tephra marker, as a pivotal tool for deciphering and correlating several temporal-spatial issues crucial for understanding the interaction between AMHs and Neandertals at the time of the Middle to Upper Palaeolithic transition
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