title: Duplication of modules facilitates the evolution of functional specialization
creator: Calabretta, Raffaele
creator: Nolfi, Stefano
creator: Parisi, Domenico
creator: Wagner, Gunter P.
subject: Behavioral Analysis
subject: Evolution
subject: Cognitive Psychology
subject: Neural Nets
subject: Robotics
subject: Neural Modelling
description: The evolution of simulated robots with three different architectures is studied. We compared a non-modular feed forward network, a hardwired modular and a duplication-based modular motor control network. We conclude that both modular architectures outperform the non-modular architecture, both in terms of rate of adaptation as well as the level of adaptation achieved. The main difference between the hardwired and duplication-based modular architectures is that in the latter the modules reached a much higher degree of functional specialization of their motor control units with regard to high level behavioral functions. The hardwired architectures reach the same level of performance, but have a more distributed assignment of functional tasks to the motor control units. We conclude that the mechanism through which functional specialization is achieved is similar to the mechanism proposed for the evolution of duplicated genes. It is found that the duplication of multifunctional modules first leads to a change in the regulation of the module, leading to a differentiation of the functional context in which the module is used. Then the module adapts to the new functional context. After this second step the system is locked into a functionally specialized state. We suggest that functional specialization may be an evolutionary absorption state.
publisher: MIT Press
contributor: Taylor, Charles E.
contributor: Langton, Christopher G.
contributor: Kitano, Hiroaki
date: 2000
type: Journal (Paginated)
type: PeerReviewed
format: application/pdf
identifier: http://cogprints.org/1304/3/calabretta.duplication.pdf
identifier:   Calabretta, Raffaele and Nolfi, Stefano and Parisi, Domenico and Wagner, Gunter P.  (2000) Duplication of modules facilitates the evolution of functional specialization.  [Journal (Paginated)]     
relation: http://cogprints.org/1304/