Language Evolution and Computation Bibliography

In this paper we present the results of an experiment in which a collection of simulated robots that are evolved for the ability to solve a collective navigation problem develop a communication system that allow them to better cooperate. The analysis of the obtained results indicates how evolving robots develop a non-trivial communication system and exploit different communication modalities.

In this article we present an evolutionary technique for developing a neural network based controller for an an- thropomorphic robotic arm with 4 DOF able to exhibit a reaching behaviour. Evolved neural controllers display an ability to reach targets accurately and generalize their ability to moving targets. This study demonstrates that it is possible to obtain solutions that are extremely parsimonious from the point of view of the control system. Evolutionary training techniques allow us to evolve parameters of the control system on the basis of the global effects that they produce on the dynamics arising from the interaction between the control system, the robot's body and the environment.

There is a growing body of research on multi-agent systems bootstrapping a communication system. Most studies are based on simulation, but recently there has been an increased interest in the properties and formal analysis of these systems. Although very interesting and promising results have been obtained in these studies, they always rely on major simplifications. For example, although much larger populations are considered than was the case in most earlier work, previous work assumes the possibility of meaning transfer. With meaning transfer, two agents always exactly know what they are talking about. This is hardly ever the case in actual communication systems, as noise corrupts the agents' perception and transfer of meaning. In this paper we first consider what happens when relaxing the meaning-transfer assumption, and propose a cross-situational learning scheme that allows a population of agents to still bootstrap a common lexicon under this condition. We empirically show the validity of the scheme and thereby improve on the results reported in (Smith, 2003) and (Vogt and Coumans, 2003) in which no satisfactory solution was found. It is not our aim to reduce the importance of previous work, instead we are excited by recent results and hope to stimulate further research by pointing towards some new challenges.

Semiotic dynamics is a novel field that studies how semiotic conventions spread and stabilize in a population of agents. This is a central issue both for theoretical and technological reasons since large system made up of communicating agents, like web communities or artificial embodied agents teams, are getting widespread. In this paper we discuss a recently introduced simple multi-agent model which is able to account for the emergence of a shared vocabulary in a population of agents. In particular we introduce a new deterministic agents' playing strategy that strongly improves the performance of the game in terms of faster convergence and reduced cognitive effort for the agents.

A set of simulations are presented that investigate generalization in languages evolved for mobile robots. The mobile robot platform is RatSLAM, a model for Simultaneous Localization and Mapping based on rodent hippocampus that uses visual and odometric information to build up a map of the explored environment. The language agents use information from this system as inputs and are based on simple recurrent neural networks. This paper describes two sets of experiments exploring the nature of generalization in evolved languages. The first study investigated languages evolved from visual inputs and the second study investigated languages evolved from position representations. These studies showed that processing the input prior to the language agent affects the expressivity of the languages and the performance of the agents. Some generalization occurs in these languages. Studies are ongoing to extend these simulations using the simulated world of the robots.