A particular game-theoretic model (Grafen, 1990) of the evolutionary stability of honest signalling, which attempts a formal proof of the validity of Zahavi's (1975, 1977) handicap principle, is generalised and rendered as an evolutionary simulation model. In addition to supporting new theoretical results, this allows the effects of differing initial conditions on the attainability of signalling equilibria to be explored. Furthermore, it allows an examination of the manner in which the character of equilibrium signalling behaviour varies with the model's parameters. It is demonstrated that (i) non-handicap signalling equilibria exist, (ii) honest signalling equilibria need not involve extravagant signals, and (iii) the basins of attraction for such equilibria are, however, relatively small. General conditions for the existence of honest signalling equilibria (which replace those offered by Zahavi) are provided, and it is demonstrated that previous theoretical results are easily accommo...

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van de academische graad van doctor in de wetenschappen, in het openbaar te verdedigen op vrijdag 8 maart 2002. Acknowledgements I started as a research assistant in the Artificial Intelligence Laboratory in autumn 1996. My first interests were into behavioural robotics and robot ecosystems. As a continuation to my “licentiaats ” thesis I started building a camera system to extend the sensory perception of the lab’s robots (Belpaeme and Birk, 1997a,b; Belpaeme, 1998; Birk and Belpaeme, 1998; Birk et al., 1998, 1999; Belpaeme and Birk, 2001). It was around that time when Luc Steels got interested in the origins of language. His early experiments formed the seed for what is now one of the most important paradigms for exploring linguistic interactions with computer simulations. Luc soon wanted more and had plans to implement a language experiment in the real world, for which I delivered the visual perception (Belpaeme et al., 1998; Belpaeme, 1999). This got me interested in visual features, and my research

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Imitation has been of great interest to students of animal social learning, but the power of simpler processes has probably been underestimated. Six classes of simple mechanisms for gaining information from the behaviour of conspecifics are considered: social facilitation, contagious behaviour, stimulus enhancement, observational learning, learning to copy, and cross-modal matching. Possible examples are given of these processes at work in the ecological domains of foraging, mating, predator avoidance, and aggression. An argument is made for the utility of evolutionary simulation models as a complement to empirical research on social learning and social information gathering.

Many of the chapters in this book have approached human language with an eye to its unique features, such as recursive syntax, or a large learned lexicon. We propose to take a wider view, seeing human language as one among many animal communication systems, and focusing on the selective pressures affecting the origin and maintenance of such systems. The possibility that human language arose from animal communication through a process of evolutionary change demands that we attend to the conceptual problems at the heart of our current understanding of animal signalling. In doing so we may throw light upon not only the origins of human language, but also its character. The chief theoretical problem that comes to light when we look at the evolution of communication is accounting for the amount of honesty that is apparently involved (Johnstone, 1997; Noble, 2000a). Let us specify a hypothetical communicative scenario, such as a warning call to alert other animals about

A simple computer program dating from the rst half of the nineteenth century is presented as the earliest known example of an evolutionary simulation model. The model is described in detail and its status as an evolutionary simulation model is discussed. Three broad issues raised by the model are presented and their signicance for modern evolutionary simulation modelling is explored: rst, the utility of attending to the character of a system's entire dynamics rather than focusing on the equilibrium states that it admits of; second, the worth of adopting an evolutionary perspective on adaptive systems beyond those addressed by evolutionary biological research; third, the potential for the non-linear character of complex dynamical systems to be explored through an individual-based simulation modelling approach. With the war-time and post-war development of the rst modern computers came a surge of research into computational theory. Seminal work by mathematicians such ...

The emergence and evolution of human language has been the focus of increasing amounts of research activity in recent years. This increasing interest has been coincident with the increased use of computer simulation, particularly using one or more of the methods and techniques of ‘Artificial Life’, to investigate a wide range of evolutionary problems and questions. There is now a significant body of work that uses such computer simulations to investigate the evolution of language. In this thesis a broad review of work on the evolution of language is presented, showing that language evolution occurs as two distinct evolutionary processes. The ability to use language is clearly the result of biological evolution. But the changes that occur over time to all spoken languages can also be viewed as being part of a process of cultural evolution. In this thesis, work using artificial life models to investigate each of these processes is reviewed. A review of the methods and techniques used in artificial life is also presented early in the work. A novel model is developed which is used to explore the conditions necessary for the

A Novel Method for Strategy Acquisition and its Application to a Double-Auction Market Game Abstract—We introduce a novel method for strategyacquisition in non-zero-sum n-player games, and empirically validate it by applying it to a well-known benchmark problem in this domain, viz the double-auction market. Many existing approaches to strategy-acquisition focus on attempting to find strategies that are robust in the sense that they are good allround performers against all-comers. We argue that in many economic and multi-agent scenarios the robustness criterion is inappropriate; in contrast, our method focusses on searching for strategies that are likely to be adopted by participating agents. We conclude by discussing several potential applications of our algorithm, including the mechanism design problem from economics. I.