Exploiting the path of least resistance in evolution

Hereditary Repulsion (HR) is a selection method coupled with a fitness constraint that substantially improves the performance and consistency of evolutionary algorithms. This also manifests as improved generalisation in the evolved GP expressions. We examine the behaviour of HR on the difficult Parity 5 problem using a population size of only 24 individuals. The negative effects of convergence are amplified under these circumstances and we progress through a series of insights and experiments which dramatically improve the consistency of the algorithm, resulting in a 70% success rate with the same small population. By contrast, a steady state GP system using a population of 5000 only had a success rate of 8%. We then confirm the effectiveness of these results in a number of arbitrary problem domains.