Abstracts

2003

  • Jorge Simão, Luís Moniz Pereira, “Social Theory Building with the Ethos Multi-Agent Simulation Framework: A Preliminary Evaluation”, submitted.
  • Abstract:
    • We present a framework for a Multi-Agent System (MAS) devised to support the modeling and simulation of agent-based models of human social behavior and culture change. The framework takes a step further than current generic MAS by providing a set of features that help the modeler to shape the model structure.

      • We describe the framework main abstractions, and make a preliminary evaluation of the their usefulness and generality by looking at how several examples and models previously published models from the literature have been re-implemented in it. We compare the framework with others and make the tentative conclusion the framework provides features that simplify the model design process for a wide range of models of social behavior, beyond what current MAS accomplish.

    Abstract
    • Jorge Simão, Luís Moniz Pereira, “Neuro-Psychological Social Theorizing and Simulation with the Computational Multi-Agent System Ethos”, invited paper at Proceedings of the Congresso em Neurociências Cognitivas, Évora, Portugal, 2003.
    Abstract:
    • Human social behaviour, culture change, and emergent social organization are amongst the most intricate phenomena studied by science. Aided by theoretical and computational tools developed to

      • study emergent phenomena in complex systems, social theorists aim to develop a unified body of knowledge that helps to shed light on long lasting question of human sociality. With this intent in
      mind, we have been developing a new conceptual framework, in the form of a Multi-Agent System (MAS) based on a simple abstraction of individuals' cognitive hardwired neuro-psychological behaviour,
      and implemented as an object-oriented computational paradigm. This framework, named Ethos, extends the traditional features provided in current MAS for agent-based modelling, with new
      abstractions specifically designed to model psychologically determined human social behaviour, culture, and organization. These include support for flexible behaviour selection mechanisms,
      including individual experience based learning, the transmission of information and social facilitation of learning, the management of agents' social networks, and the definition of the task-environments that structure an agent's action and interaction. This is accomplished by providing an object-oriented
      framework with a relatively small set of main interfaces and top classes abstracting key theoretical constructs, and having the modeler selectively sub-class filling the basic object structure
      to implement her/his own model. Thus the Ethos class structure provides a meta-model, which can be instantiated in a flexible manner to implement each concrete model of individual
      human social behaviour. In addition to presenting the general framework, we report on our own experiences in using Ethos to (re)implement several models we have developed. This includes
      models of human mate choice strategies and emergent human mating systems, and of the cultural dynamics of preferences such as identification of fashion-like product careers. We argue that
      providing the type of functionality afforded by Ethos, off-the-self, substantially improves theoretical integration and facilitates model comparison. It can also be of great help to
      students of social and cognitive science who wish to develop theoretical work based on tested, established, and accepted computational building blocks.
    • Jorge Simão, Peter M. Todd, Luís Moniz Pereira, “What's Cool? - Modelling Fashion-like Collective Behavior Emergence from Individual Neuro-psychological Conditioning”, submitted.

    Abstract:
    • In this article we have presented a simple model that shows how mechanisms of neuro-psychological conditioning at the individual level can generate the emergence of fashion-like collective behavior. The model shows that for even moderate levels of social assortment, trait usage can oscillate continuously between stable periods of near full trait use to near total trait avoidance.
    • Jorge Simão, Peter M. Todd, “Emergent Patterns of Mate Choice in Human Populations”, special issue of Journal of Artifical Life , (to appear), 2003.

    Abstract:
    • We present a model of human mate choice that shows how realistic population-level patterns of assortative mating can self-organize and emerge from the behavior of individuals using simple mate search rules.  In particular, we model plausible psychological mechanisms for mate search and choice in a realistic social ecology.  Through individual interactions, patterns emerge that match those observed in typical human societies, particularly in terms of correlated quality levels within couples, distributions of the ages at which couples mate, and effects of skewed sex ratios on these mating age distributions.

    Abstract:
    • We present a framework for a Multi-Agent System (MAS) devised to support the modelling and simulation of agent-based models of human social behavior and culture change. We set forth its main abstractions, and test the usefulness and generality of the framework by describing how two previously published models from the literature have been re-implemented in it. We argue that our framework provides features that simplify the modelling process of a wide range of models of human social behavior, beyond what current MAS accomplish.

    2002

    • Jorge Simão, Peter M. Todd, “Modeling Mate Choice in Monogamous Mating Systems with Courtship”, Journal of Adaptive Behavior, 10(2), 2002.

    Abstract:
    • We present a conceptual framework for the study of mate choice in monogamous mating systems with non-negligible courtship time. Within this framework, we develop a mate choice model for the common case where individuals have a changing social network of potential partners. We evaluate the performance and robustness of different agent strategies, emphasizing the important role that courtship plays in mate choice. Specifically, the courtship period can be used by individuals to swap to better partners when they become available. We found that using courtship as a mechanism for holding partners before full commitment to mating provides strategic advantages relative to sequential search using aspiration levels.  Moreover, simple heuristics that require little computation provide a degree of robustness to environmental (parameter) changes that is unattainable by strategies based on more extensive information processing. Our model produces realistic patterns of assortative mating (high within-couple mate value correlations) and rates of mating that match empirical data on human sexual/romantic relationships much more closely than previous accounts from biology and the social sciences.

    Abstract:
    • We present a model of human mate choice that shows how realistic population-level patterns of assortative mating can self-organize from the behavior of individuals using simple mate search rules.  In particular, we model evolutionarily plausible psychological mechanisms for mate search and choice set in a realistic social ecology.  Through individual interactions, patterns emerge that match those observed in typical human societies, particularly in terms of correlated quality levels within couples and of distributions of the ages at which couples mate.
    • Jorge Simão, “Tools Evolve: The Artifical Selection and Evolution of Paleolithic Stone Tools”, Commentary on  “Thomas Wynn, Archaeology and cognitive evolution”, Behavioral and Brain Sciences, 25:4, 2002.

    Abstract:
    • I claim that the increase in complexity in the (known) trace of Paleolithic stone tools can be parsimoniously explained by postulating the emergence of effective mechanisms for the social transmission of representations. I propose that Paleolithic tools, similar to more contemporary tools, were subject to a process of evolution by artificial selection based on functionality.

    2001

    • Jorge Simão, Peter M. Todd, “A Model of Human Mate Choice with Courtship that Predicts Population Patterns”, in “Advances in Artificial Life, 6th. European Conference, ECAL 2001, Prague, Czech Republic”, Jozef Kelemen, Petr Sosík (Eds.), Springer, Lecture Notes in Artificial Intelligence 2159, September 2001.

    Abstract:
    • In this paper, we present a new model of human mate choice based on non negligible courtship time. The courtship period is used by individuals to strategically swap to better partners when they become available. The model is then extended to introduce costs for being in a relationship, namely, a reduction in the possibility of interacting with individuals of the opposite sex (the potential future partners). Given this constraint, individuals must strategically decide under which conditions to start a relationship. The model makes several predictions about human sexual/romantic relationship patterns, many of which are supported by relevant empirical data and theoretical work described in the social sciences literature.

    PhD Thesis

    • “Computational Modelling and Simulation of Human Social Behavior and Culture”, New University of Lisbon, Lisbon, 2003. 

    Abstract:
    • In this thesis, we focus on the issue of using computer models to study human social behavior and culture. We present a new software multi-agent system (MAS), named Ethos, specially designed for this target domain. This framework goes a step beyond what currently available MAS provide by allowing a number of abstractions related to the domain to be used to specify agent-based models in a simple manner. This includes: flexible behavior selection mechanisms, social influence through participation in shared activities, management of agents' social relationships, and flexible event scheduling. We present the MAS framework abstractions, and describe its design and implementation.


      • To test the usefulness and generality of the framework we present two new models of human social behavior. The first one is intended to study population patterns of human mate choice, making substantiated prediction on areas such as degree of assortment, relationship stability, age of mating, and sex ratio effects.

      The second model tries to explain fashion like collective phenomena in terms of individuals neuro-psychological conditioning. We conclude that providing domain specific abstractions facilitates the task of designing agent-based models and speed its implementation..