abstract = "Bloat is one of the most widely studied phenomena in
Genetic Programming (GP), it is normally defined as the
increase in mean program size without a corresponding
improvement in fitness. Several theories have been
proposed in the specialized GP literature that explain
why bloat occurs. In particular, the Crossover-Bias
Theory states that the cause of bloat is that the
distribution of program sizes during evolution is
skewed in a way that encourages bloat to appear, by
punishing small individuals and favouring larger ones.
Therefore, several bloat control methods have been
proposed that attempt to explicitly control the size
distribution of programs within the evolving
population. This work proposes a new bloat control
method called neat-GP, that implicitly shapes the
program size distribution during a GP run. neat-GP is
based on two key elements: (a) the NeuroEvolution of
Augmenting Topologies algorithm (NEAT), a robust
heuristic that was originally developed to evolve
neural networks; and (b) the Flat Operator Equalization
bloat control method, that explicitly shapes the
program size distributions toward a uniform or flat
shape. Experimental results are encouraging in two
domains, symbolic regression and classification of
real-world data. neat-GP can curtail the effects of
bloat without sacrificing performance, outperforming
both standard GP and the Flat-OE method, without
incurring in the computational overhead reported by
some state-of-the-art bloat control methods",