Material Representations

From the Genetic Code to the Evolution of Cellular Automata

School of Informatics and Cognitive Science Program
Indiana University
1900 East Tenth Street, Bloomington IN 47408

Santa Fe Institute
1399 Hyde Park Road
Santa Fe, NM 86501, USA

Citation: L. M. Rocha and W. Hordijk [2005]. Artificial Life. Vol. 11, Issues 1-2, pp. 189 - 214 - Winter-Spring 2005. Special Issue on Embodied and Situated Cognition. Preprint available in pdf format.

This is the paper that came out of a talk prepared for the International interdisciplinary seminar on new robotics, evolution and embodied cognition (IISREEC).12th to 15th November 2002, Lisbon, Portugal


We present a new definition of the concept of representation for cognitive science that is based on a study of the origin of structures that are used to store memory in evolving systems. This study consists of novel computer experiments in the evolution of cellular automata to perform nontrivial tasks as well as evidence from biology concerning genetic memory. Our key observation is that representations require inert structures to encode information used to construct appropriate dynamic configurations for the evolving system. We propose criteria to decide if a given structure is a representation by unpacking the idea of inert structures that can be used as memory for arbitrary dynamic configurations. Using a genetic algorithm, we evolved cellular automata rules that can perform nontrivial tasks related to the density task (or majority classification problem) commonly used in the literature. We present the particle catalogs of the new rules following the computational mechanics framework. We discuss if the evolved cellular automata particles may be seen as representations according to our criteria. We show that while they capture some of the essential characteristics of representations, they lack an essential one. Our goal is to show that artificial life can be used to shed new light on the computation-versus-dynamics debate in cognitive science, and indeed function as a constructive bridge between the two camps. Our definitions of representation and cellular automata experiments are proposed as a complementary approach, with both dynamics and informational modes of explanation.

Keywords:Representation, cellular automata, evolutionary computation, artificial life, cognitive science, symbols, genetic code, memory

For the full paper please download the pdf version

For more information contact Luis Rocha at
Last Modified: May 29, 2005