Language Evolution and Computation Bibliography

Social coordination is studied in a simulated model of autonomous embodied agents that interact acoustically. Theoretical concepts concerning social behavior are presented from a systemic perspective and their usefulness is evaluated in interpreting the results obtained. Two agents moving in an unstructured arena must locate each other, and remain within a short distance of one another for as long as possible using noisy continuous acoustic interaction. Evolved dynamical recurrent neural networks are used as the control architecture. Acoustic coupling poses nontrivial problems like discriminating `self' from `non-self' and structuring production of signals in time so as to minimize interference. Detailed observation of the most frequently evolved behavioral strategy shows that interacting agents perform rhythmic signals leading to the coordination of movement. During coordination, signals become entrained in an anti-phase mode that resembles turn-taking. Perturbation techniques show that signalling behavior not only performs an external function, but it is also integrated into the movement of the producing agent, thus showing the difficulty of separating behavior into social and non- social classes. Structural congruence between agents is shown by exploring internal dynamics as well as the response of single agents in the presence of signalling beacons that reproduce the signal patterns of the interacting agents. Lack of entrainment with the signals produced by the beacons shows the importance of transient periods of mutual dynamic perturbation wherein agents achieve congruence.

An exploration is presented of the interplay between the situated activity of embodied autonomous organisms and the social dynamics they constitute in interaction, with special emphasis on evolutionary, ecological and behavioral aspects. The thesis offers a series of theoretical and methodological criticisms of recent investigations on the biology of social behavior and animal communication. An alternative theoretical framework, based on a systemic theory of biological autonomy, is provided to meet these criticisms and the elaboration of the corresponding theoretical arguments is supported by the construction and analysis of mathematical and computational models.

A game of action coordination is studied by a series of game-theoretic, ecological and computational models which, by means of systematic comparisons, permit the identification of the evolutionary relevance of different factors like finite populations, ecological and genetic constraints, spatial patterns, discreteness and stochasticity. Only in an individual-based model is it found that cooperative action coordination is evolutionarily stable. This is due to the emergence of spatial clusters in the spatial distribution of players which break many of the in-built symmetries of the game and act as invariants of the dynamics constraining the path of viable evolution.

An extension to this model explores other structuring effects by adding the possibility of parental influences on phenotypic development. The result is a further stabilization of cooperative coordination which is explained by the presence of self-promoting networks of developmental relationships which enslave the evolutionary dynamics.

The behavioral aspects involved in the attainment of a coordinated state between autonomous systems are studied in a simulated model of embodied agents coupled through an acoustic medium. Agents must locate and approach each other only by means of continuous acoustic signals. The results show the emergence of synchronized rhythmic signalling patterns that resemble turn-taking which is accompanied by coherent patterns of movement. It is demonstrated that coordination results from the achievement of structural congruence between the agents during interaction.

This article presents a theoretical criticism of current approaches to the study of the evolution of communication. In particular two very common preconceptions about the subject are analysed: the role of natural selection in the definition of the phenomenon and the metaphor of communication as information exchange. An alternative characterization is presented in terms of autopoietic theory which avoids the mentioned preconceptions. In support of this view, the evolution of coordinated activity is studied in a population of artificial agents playing an interactional game. Dynamical modeling of this evolutionary process based on game-theoretic considerations shows the existence of an evolutionarily stable strategy in the total lack of coordinated activity which, however, may be unreachable due to the presence of a periodic attractor. In a computational model of the same game, action coordination evolves, even with individual costs against it, due to the presence of spatial structuring processes. A detailed explanation of this phenomenon, which does not require kin selection, is presented. In an extended game, recursive coordination evolves nontrivially when the participants share all the relevant information, demonstrating that the metaphor of information exchange can be misleading. It is shown that agents engaged in this sort of interaction are able to perform beyond their individual capabilities.