Against the inappropriate use of numerical representation in social simulation

All tools have their advantages and disadvantages and for all tools there are times when they are appropriate and times when they are not. Formal tools are no exception to this and systems of numbers are examples of such formal tools. Thus there will be occasions where using a number to represent something is helpful and times where it is not. To use a tool well one needs to understand that tool and, in particular, when it may be inadvisable to use it and what its weaknesses are. However we are in an age that it obsessed by numbers. Governments spend large amounts of money training its citizens in how to use numbers and their declarative abstractions (graphs, algebra etc.) We are surrounded by numbers every day in: the news, whether forecasts, our speedometers and our bank balance. We are used to using numbers in loose, almost “conversational” ways – as with such concepts as the rate of inflation and our own “IQ”. Numbers have become so famliar that we no more worry about when and why we use them than we do about natural language. We have lost the warning bells in our head that remind us that we may be using numbers inappropriately. They have entered (and sometimes dominate) our language of thought. Computers have exasperbated this trend by making numbers very much easier to store/manipulate/communicate and more seductive by making possible attractive pictures and animations of their patterns. More subtley, when thought of as calculating machines that can play games with us and simulate the detail of physical systems, they suggest that everything comes down to numbers. For this reason it is second nature for us to use numbers in our social simulations and we frequently do so without considering the consequences of this choice. This paper is simply a reminder about numbers: a call to remember that they are just another (formal) tool; it recaps some of the conditions which indicate when a number is applicable and when it might be misleading; it looks at some of the dangers and pitfalls of using numbers; it considers some examples of the use of numbers; and it points out that we now have some viable alternatives to numbers that are not any less formal but which may be often preferable

The Logic of the Method of Agent-Based Simulation in the Social Sciences: Empirical and Intentional Adequacy of Computer Programs

The classical theory of computation does not represent an adequate model of reality for simulation in the social sciences. The aim of this paper is to construct a methodological perspective that is able to conciliate the formal and empirical logic of program verification in computer science, with the interpretative and multiparadigmatic logic of the social sciences. We attempt to evaluate whether social simulation implies an additional perspective about the way one can understand the concepts of program and computation. We demonstrate that the logic of social simulation implies at least two distinct types of program verifications that reflect an epistemological distinction in the kind of knowledge one can have about programs. Computer programs seem to possess a causal capability (Fetzer, 1999) and an intentional capability that scientific theories seem not to possess. This distinction is associated with two types of program verification, which we call empirical and intentional verification. We demonstrate, by this means, that computational phenomena are also intentional phenomena, and that such is particularly manifest in agent-based social simulation. Ascertaining the credibility of results in social simulation requires a focus on the identification of a new category of knowledge we can have about computer programs. This knowledge should be considered an outcome of an experimental exercise, albeit not empirical, acquired within a context of limited consensus. The perspective of intentional computation seems to be the only one possible to reflect the multiparadigmatic character of social science in terms of agent-based computational social science. We contribute, additionally, to the clarification of several questions that are found in the methodological perspectives of the discipline, such as the computational nature, the logic of program scalability, and the multiparadigmatic character of agent-based simulation in the social sciences.Computer and Social Sciences, Agent-Based Simulation, Intentional Computation, Program Verification, Intentional Verification, Scientific Knowledge

The Logic of the Method of Agent-Based Simulation in the Social Sciences: Empirical and Intentional Adequacy of Computer Programs

The classical theory of computation does not represent an adequate model of reality for simulation in the social sciences. The aim of this paper is to construct a methodological perspective that is able to conciliate the formal and empirical logic of program verification in computer science, with the interpretative and multiparadigmatic logic of the social sciences. We attempt to evaluate whether social simulation implies an additional perspective about the way one can understand the concepts of program and computation. We demonstrate that the logic of social simulation implies at least two distinct types of program verifications that reflect an epistemological distinction in the kind of knowledge one can have about programs. Computer programs seem to possess a causal capability (Fetzer, 1999) and an intentional capability that scientific theories seem not to possess. This distinction is associated with two types of program verification, which we call empirical and intentional verification. We demonstrate, by this means, that computational phenomena are also intentional phenomena, and that such is particularly manifest in agent-based social simulation. Ascertaining the credibility of results in social simulation requires a focus on the identification of a new category of knowledge we can have about computer programs. This knowledge should be considered an outcome of an experimental exercise, albeit not empirical, acquired within a context of limited consensus. The perspective of intentional computation seems to be the only one possible to reflect the multiparadigmatic character of social science in terms of agent-based computational social science. We contribute, additionally, to the clarification of several questions that are found in the methodological perspectives of the discipline, such as the computational nature, the logic of program scalability, and the multiparadigmatic character of agent-based simulation in the social sciences

The logic of the method of agent-based simulation in the social sciences: Empirical and intentional adequacy of computer programs

WOS:000235217900009 (Nº de Acesso Web of Science)The classical theory of computation does not represent an adequate model of reality for simulation in the social sciences. The aim of this paper is to construct a methodological perspective that is able to conciliate the formal and empirical logic of program verification in computer science, with the interpretative and multiparadigmatic logic of the social sciences. We attempt to evaluate whether social simulation implies an additional perspective about the way one can understand the concepts of program and computation. We demonstrate that the logic of social simulation implies at least two distinct types of program verifications that reflect an epistemological distinction in the kind of knowledge one can have about programs. Computer programs seem to possess a causal capability (Fetzer, 1999) and an intentional capability that scientific theories seem not to possess. This distinction is associated with two types of program verification, which we call empirical and intentional verification. We demonstrate, by this means, that computational phenomena are also intentional phenomena, and that such is particularly manifest in agent-based social simulation. Ascertaining the credibility of results in social simulation requires a focus on the identification of a new category of knowledge we can have about computer programs. This knowledge should be considered an outcome of an experimental exercise, albeit not empirical, acquired within a context of limited consensus. The perspective of intentional computation seems to be the only one possible to reflect the multiparadigmatic character of social science in terms of agent-based computational social science. We contribute, additionally, to the clarification of several questions that are found in the methodological perspectives of the discipline, such as the computational nature, the logic of program scalability, and the multiparadigmatic character of agent-based simulation in the social sciences

Implementations, interpretative malleability, value-ladenness and the moral significance of agent-based social simulations

The focus of social simulation on representing the social world calls for an investigation of whether its implementations are inherently value-laden. In this article, I investigate what kind of thing implementation is in social simulation and consider the extent to which it has moral significance. When the purpose of a computational artefact is simulating human institutions, designers with different value judgements may have rational reasons for developing different implementations. I provide three arguments to show that different implementations amount to taking moral stands via the artefact. First, the meaning of a social simulation is not homogeneous among its users, which indicates that simulations have high interpretive malleability. I place malleability as the condition of simulation to be a metaphorical vehicle for representing the social world, allowing for different value judgements about the institutional world that the artefact is expected to simulate. Second, simulating the social world involves distinguishing between malfunction of the artefact and representation gaps, which reflect the role of meaning in simulating the social world and how meaning may or not remain coherent among the models that constitute a single implementation. Third, social simulations are akin to Kroes’ (2012) techno-symbolic artefacts, in which the artefact’s effectiveness relative to a purpose hinges not only on the functional effectiveness of the artefact’s structure, but also on the artefact’s meaning. Meaning, not just technical function, makes implementations morally appraisable relative to a purpose. I investigate Schelling’s model of ethnic residential segregation as an example, in which different implementations amount to taking different moral stands via the artefact.info:eu-repo/semantics/acceptedVersio

O papel da emergência em simulações de sociedades de agentes artificiais

Não há disciplina científica, a partir da segunda metade do século XX, que tenha contribuído de modo tão profundo para o ressurgimento do interesse científico e filosófico pelo conceito de "emergência" como a simulação computacional de sistemas complexos. Os modelos de simulação pertencem a uma classe de modelos distintos dos modelos teóricos tratáveis através de métodos analíticos. Embora possam ser baseados em modelos teóricos, a sua implementação em um computador implica um rol de tratamentos formais e informais, através de uma cadeia de transformação em sucessivos outros modelos, que torna o produto final de alguma forma autônomo da teoria ou do modelo que lhe deu origem.info:eu-repo/semantics/publishedVersio

Relating Structure and Dynamics in Organisation Models

To understand how an organisational structure relates to dynamics is an interesting fundamental challenge in the area of social modelling. Specifications of organisational structure usually have a diagrammatic form that abstracts from more detailed dynamics. Dynamic properties of agent systems, on the other hand, are often specified in the form of a set of logical formulae in some temporal language. This paper addresses the question how these two perspectives can be combined in one framework. It is shown how for different aggregation levels within an organisation structure, sets of dynamic properties can be specified. Organisational structure provides a structure of interlevel relationships between these multiple sets of dynamic properties. Thus organisational structure relates to specification of the dynamics of organisational behaviour. As an illustration, for Ferber and Gutknecht's AGR organisation modelling approach it is shown how a foundation can be obtained for integrated specification of both structure and dynamic properties of an organisation

Exploration, design and analysis of social spaces for social simulation models

Tese de mestrado em Engenharia Informática, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2012Em simulação social, a estrutura das relações sociais é não só fundamental para a concepção de cenários de simulação plausíveis, mas também para a compreensão de processos de interação guiados por tais estruturas. Cada ator interage em múltiplos contextos integrados em múltiplas relações que constituem o seu espaço social. Nesta tese, tomando como base o trabalho prévio acerca de modelos de trocas de contextos sociais, é estudada a noção de segregação social e seu impacto na disseminação dos fenómenos através da sociedade. Os agentes não só trocam entre contextos sociais, levando com eles a sua identidade social única, mas também escolhem os contextos de acordo com razões pessoais. A noção de segregação entre contextos é aplicada a um jogo de consensos simples. Neste jogo, os agentes tentam coletivamente alcançar um consenso sobre uma opinião ou escolha binária que devem fazer. Este trabalho compreende o desenho e análise de um conjunto de experiências destinadas à observação da influência de mecanismos de segregação na velocidade de convergência para um consenso global numa sociedade de agentes. É criado um modelo onde existe uma abstração de escolha estratégica de vizinhanças (os contextos sociais). Neste modelo, um conjunto de valores de tolerância associados a cada contexto social define um limiar para que uma vizinhança seja considerada adequada ou não. Um agente decide trocar de contexto se o número de vizinhos a adoptar uma escolha contrária à sua esteja acima da tolerância definida para o contexto corrente. Os resultados do modelo concebido são posteriormente comparados com os resultados do modelo de troca de contextos previamente desenvolvido. Neste trabalho, é confirmada a hipótese feita sobre um modelo de troca de contextos desenvolvido anteriormente. A primeira conjetura confirmada é que a formação de consensos locais ajuda à aceleração da convergência da sociedade para um consenso global, especialmente se esses grupos de consenso local tiverem as condições estruturais adequadas para serem criados. Uma ideia interessante é que nas condições certas, as dinâmicas de formação de grupos de consenso podem ser localizadas e relacionadas com determinadas topologias construídas à custa de várias redes sociais. Este facto é especialmente interessante para o desenvolvimento de estudos de disseminação de informação em estruturas sociais bem conhecidas como campanhas políticas ou de marketing em redes sociais on-line. As experiências concretizadas sobre o mecanismo de segregação apresentado mostraram resultados interessantes. Foi observado que, sob as condições adequadas, a segregação acelera a convergência para um consenso global. É curioso observar que este mecanismo não só acelera a velocidade de auto-organização da sociedade de agentes, mas também é transversal às estruturas sociais utilizadas. Por outras palavras, o efeito de otimização de convergência para um consenso é observado para diferentes redes sociais. Ainda mais intrigante é esta otimização se manter mesmo quando é aumentado o número de relações sociais concomitantes. Foi ainda verificado que o mecanismo introduzido não altera drasticamente o comportamento do modelo de troca de contextos anteriormente desenvolvido. Globalmente, as tendências de frequência de troca entre contextos são preservadas mantendo-se fortemente relacionadas com a probabilidade de trocar de contexto social (parâmetro integrante do modelo de troca de contextos que define, de forma abstrata, o tempo que cada agente passa em cada um dos contextos sociais). Adicionalmente ao modelo de simulação social desenvolvido, foi feita uma recolha extensa do estado da arte referente a simulação, simulação baseada em agentes e dos mais recentes avanços em simulação social relacionados com o trabalho desenvolvido. Para além de métodos e modelos de simulação, foi feita uma recolha de modelos generativos de redes sociais complexas bem como uma detalhada apresentação de alguns conceitos base. É feita uma revisão sobre conceitos base de teoria de grafos e análise de redes sociais. Neste último tópico são incluídas algumas das medidas que podem ser feitas sobre estruturas como redes sociais. Estas são fundamentais para compreensão dos modelos generativos apresentados. A concepção de modelos de simulação social requer que um conjunto de componentes sejam modeladas antes que uma experiencia possa ser concebida. Estes componentes não estão normalmente desacoplados dos processos experimentais, o que cria um problema relativamente à reprodução e reusabilidade de modelos. Para contribuir com uma solução para este problema, esta tese fornece alguns avanços no desenvolvimento da b-have workbench. Este é um projecto dedicado à criação de componentes reutilizáveis para modelos de simulação social. Tais componentes compreendem: redes sociais complexas, modelos de agentes, regras comportamentais e modelos abstractos de ambientes. Estes componentes introduzem uma separação entre processos de modelação e simulação. O foco do trabalho realizado neste contexto, é na criação de modelos de redes sociais complexas posteriormente integradas no modelo desenvolvido de segregação entre contextos. Para cumprir este objectivo, foi criada uma API (Application Programming Interface) para permitir a criação de instâncias de redes sociais em Java, API essa que está integrada no âmbito do desenvolvimento da plataforma b-have workbench. Finalmente, este trabalho aborda outro problema da simulação social, a criação de uma infra-estrutura adequada para o desenvolvimento e execução de simulações de uma forma escalável. A exploração de modelos de simulação social baseados em agentes leva muitas vezes demasiado tempo para que seja obtida uma quantidade de resultados suficiente para uma análise significativa dos dados gerados. Nesta tese é feita uma análise do problema e fornecida uma solução que o minimiza utilizando computação em grelha. Este trabalho fornece uma discussão detalhada acerca de processos de construção de modelos de simulação social bem como de desenho e distribuição de experiências utilizando uma grelha de computadores. Esta infraestrutura é posteriormente utilizada para a execução de experiências sobre o modelo de simulação social desenvolvido.In social simulation, the structure of the social relations is not only fundamental for the construction of plausible scenarios, but also important to construct an understanding of interaction processes shaped by such structures. Each actor interacts in multiple social contexts located within multiple social relations that constitute their social space. In this thesis, we build on previous work about context switching to study the notion of context segregation. The agents not only switch between social contexts, carrying with them their unique social identity, but also choose the contexts according to personal reasons. We apply the notion of context segregation to a simple game of consensus in which agents try to collectively achieve an essentially arbitrary consensus. This work comprehends the design and analysis of a set of experiments towards the understanding of the inuence of the segregation mechanism in the speed of convergence to global consensus, comparing the results with the previous model of context switching. Social simulation requires a series of components to be modelled prior to the experiment set-up. These components are usually not decoupled from the experiment process. This creates a problem of experiment reproduction and model reusability. To contribute with a solution to this problem, this thesis also provides advances to the development of the b-have workbench. This is a project dedicated to the creation of reusable social simulation components such as complex social networks, agent models, behaviour rules, and environment abstract models. We focus on the creation of complex social network models and integrate them in our model of context segregation. An extensive review over the state-of-the-art on simulation methods, agent-based simulation and social simulation models is also presented in this thesis. Moreover we have also reviewed a series of generative models for complex network structures and the basic associated with it. We describe the fundamental background on graph theory and social network analysis. Within social network analysis, we present a series of measurements essential for the understanding of the network models here presented. Finally, this work tackles another problem in social simulation, the creation of a proper infrastructure for scalable simulation deployment. The exploration of agentbased social simulation models often takes too much time to get enough results for a signi_cant analysis of the data generated. In this thesis, we show how to minimise this problem by using grid computing. We provide insights on social simulation model construction, experiment design and experiment distribution using a computer grid. The developed infrastructure is then used to deploy the social simulation model created

La diversidad cultural del primer neolítico (VII cal. BP) en el mediterráneo occidental. Una análisis desde los sistemas complejos y la simulación basada en agentes

Esta tesis doctoral aborda el estudio de la variabilidad cultural del primer Neolítico en el Mediterráneo occidental partiendo de la hipótesis del autoestop cultural. En este contexto el principal objetivo ligado a la expansión del Neolítico que queremos contestar con la elaboración de la presente tesis doctoral es cuál fue el mecanismo o mecanismos de transmisión que afectaron en la formación de las culturas neolíticas del Mediterráneo occidental. Dicho de otro modo, nuestra intención es investigar si existe un patrón cultural claro que podría estar relacionado con una expansión desde el sur de Italia, y si dicha homogeneidad debe asociarse a la hipótesis del autoestop cultural "Cultural hitchhiking". Para abordar los objetivos formulados se han aplicado los conceptos propios de la teoría evolutiva y los Sistemas Complejos Adaptativos "CAS" ya que los postulados evolutivos permiten establecer las reglas y habilidades de los agentes así como las propias características de los CAS permitirá elaborar diferentes modelos con los que se obtendrán numerosos resultados para ser comparados con el registro arqueológico disponible. La metodología utilizada es la aplicación de las simulaciones computacionales, y más en concreto, los modelos basados en agentes. Estos resultan de especial interés en las ciencias humanas ya que sus propiedades los hacen realmente útil para plantear diferentes escenarios virtuales que serán cotejados con la información arqueológica. En definitiva, la tesis pone de manifiesto la importancia de integrar la modelización computacional como método dentro de la investigación prehistórica. Además. la investigación llevada a cabo resulta complementaria a los diferentes trabajos de investigación elaborados en torno a la expansión de los primeros grupos neolíticos en en Europa en general y en el Mediterráneo occidental en particular