Both the Ant and Parity experiments contain varying levels of correlation between edit distance and fitness and between phenotype diversity and fitness. The Quartic experiments contains a period of early fluctuation, followed by an increase in positive correlation between entropy (and phenotype diversity) and fitness. As runs typically achieve the best fitness early, this effect may be due to many copies of the best fit individual accumulating in the population. That is, populations which achieve good local optima begin to have lower entropy.
The Rastrigin experiments contain an early period of varying correlation between diversity and fitness, after which most measures lost correlation with fitness. In this problem and representation, the relationship between fitness and diversity becomes less important, probably due to other more critical relationships like node-to-node dependencies [Daida et al., 2001]. A positive correlation between fitness and edit distance occurs together with a negative correlation between fitness and phenotype diversity is seen in the Ant and Parity experiments. These results suggest that the fitness landscape induced by the representation, operator and fitness function is uncorrelated. Small differences between individuals are still capable of expressing a wide range of behaviours. However, this statement should be considered in the light of the operator not being used to define distance and the actual difference between behaviours is not considered. The measures used here only give approximate descriptions of the fitness landscape.