  Evolution depends on the possibility of successfully exploring fitness
landscapes via mutation and recombination. With these search procedures,
exploration is difficult in "rugged" fitness landscapes, where small mutations
can drastically change functionalities in an organism. Random Boolean networks
(RBNs), being general models, can be used to explore theories of how evolution
can take place in rugged landscapes; or even change the landscapes.
  In this paper, we study the effect that redundant nodes have on the
robustness of RBNs. Using computer simulations, we have found that the addition
of redundant nodes to RBNs increases their robustness. We conjecture that
redundancy is a way of "smoothening" fitness landscapes. Therefore, redundancy
can facilitate evolutionary searches. However, too much redundancy could reduce
the rate of adaptation of an evolutionary process. Our results also provide
supporting evidence in favour of Kauffman's conjecture (Kauffman, 2000, p.195).
