
228 Chapter 8 GenetiC alGorithms
A schema helps when searching for good regions of the search space
corresponding to regularities in the problem domain. For example, a short,
low-order, above-average schema receives exponentially increasing trials in
subsequent generations of a genetic algorithm. During crossover, these “build-
ing blocks” become exchanged and combined. According to Building Block
Hypothesis (Hayes, 2007), the genetic algorithm initially detects biases towards
higher fitness in some low-order schemas (with a small number of defined
bits) and over time, detects the same in high-order schemas. Holland (1975)
determined ...