Code Growth is Not Caused by Introns
Late Breaking Papers at the 2000 Genetic and
Evolutionary Computation Conference, page 228--235. Las Vegas, Nevada, USA, (8 July 2000)Abstract
Genetic programming trees have a strong tendency to
grow rapidly and relatively independent of fitness, a
serious flaw which has received considerable attention
in the genetic programming literature. Much of this
literature has implicated introns, subtree structures
with no effect on the an individual's fitness
assessment. The propagation of inviable code, a certain
kind of intron, has been especially linked to tree
growth. However this paper presents evidence which
shows that denying inviable code the opportunity to
propagate actually increases tree growth. The paper
argues that rather than causing tree growth, a rise in
inviable code is in fact an expected result of tree
growth. Lastly, this paper proposes a more general
theory of growth for which introns are merely a
symptom.