[attachment=5400]
The evolutionary engine and the mind machine:
A design-based study of adaptive change

by

Christopher Complin




Abstract

The objectives of this thesis are to elucidate adaptive change from a design-stance, provide a detailed examination of the concept of evolvability and computationally model agents which undergo both genetic and cultural evolution. Using Sloman’s (1994) design-based methodology, Darwinian evolution by natural selection is taken as a starting point. The concept of adaptive change is analysed and the situations where it is necessary for survival are described. A wide array of literature from biology and evolutionary computation is used to support the thesis that Darwinian evolution by natural selection is not a completely random process of trial and error, but has mechanisms which produce trial-selectivity. A number of means of creating trial-selectivity are presented, including reproductive, developmental, psychological and sociocultural mechanisms. From this discussion, a richer concept of evolvability than that originally postulated by Dawkins (1989) is expounded. Computational experiments are used to show that the evolvability producing mechanisms can be selected as they yield, on average, ‘fitter’ members in the next generation that inherit those same mechanisms. Thus Darwinian evolution by natural selection is shown to be an inherently adaptive algorithm that can tailor itself to searching in different areas of design space. A second set of computational experiments are used to explore a trajectory in design space made up of agents with genetic mechanisms, agents with learning mechanisms and agents with social mechanisms. On the basis of design work the consequences of combining genetic and cultural evolutionary systems were examined; the implementation work demonstrated that agents with both systems could adapt at a faster rate. The work in this thesis supports the conjecture that evolution involves a change in replicator frequency (genetic or memetic) through the process of selective-trial and error-elimination.