A model for the emergence of adaptive subsystems

We investigate the interaction of learning and evolution in a changing environment. A stable learning capability is regarded as an emergent adaptive system evolved by natural selection of genetic variants. We consider the evolution of an asexual population. Each genotype can have 'fixed' a...

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Autores principales: Dopazo, H., Gordon, M.B., Perazzo, R., Risau-Gusman, S.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00928240_v65_n1_p27_Dopazo
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00928240_v65_n1_p27_Dopazo
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spelling todo:paper_00928240_v65_n1_p27_Dopazo2023-10-03T14:55:18Z A model for the emergence of adaptive subsystems Dopazo, H. Gordon, M.B. Perazzo, R. Risau-Gusman, S. We investigate the interaction of learning and evolution in a changing environment. A stable learning capability is regarded as an emergent adaptive system evolved by natural selection of genetic variants. We consider the evolution of an asexual population. Each genotype can have 'fixed' and 'flexible' alleles. The former express themselves as synaptic connections that remain unchanged during ontogeny and the latter as synapses that can be adjusted through a learning algorithm. Evolution is modelled using genetic algorithms and the changing environment is represented by two optimal synaptic patterns that alternate a fixed number of times during the 'life' of the individuals. The amplitude of the change is related to the Hamming distance between the two optimal patterns and the rate of change to the frequency with which both exchange roles. This model is an extension of that of Hinton and Nowlan in which the fitness is given by a probabilistic measure of the Hamming distance to the optimum. We find that two types of evolutionary pathways are possible depending upon how difficult (costly) it is to cope with the changes of the environment. In one case the population loses the learning ability, and the individuals inherit fixed synapses that are optimal in only one of the environmental states. In the other case a flexible subsystem emerges that allows the individuals to adapt to the changes of the environment. The model helps us to understand how an adaptive subsystem can emerge as the result of the tradeoff between the exploitation of a congenital structure and the exploration of the adaptive capabilities practised by learning. © 2002 Society for Mathematical Biology. Published by Elsevier Science Ltd. All rights reserved. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00928240_v65_n1_p27_Dopazo
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
description We investigate the interaction of learning and evolution in a changing environment. A stable learning capability is regarded as an emergent adaptive system evolved by natural selection of genetic variants. We consider the evolution of an asexual population. Each genotype can have 'fixed' and 'flexible' alleles. The former express themselves as synaptic connections that remain unchanged during ontogeny and the latter as synapses that can be adjusted through a learning algorithm. Evolution is modelled using genetic algorithms and the changing environment is represented by two optimal synaptic patterns that alternate a fixed number of times during the 'life' of the individuals. The amplitude of the change is related to the Hamming distance between the two optimal patterns and the rate of change to the frequency with which both exchange roles. This model is an extension of that of Hinton and Nowlan in which the fitness is given by a probabilistic measure of the Hamming distance to the optimum. We find that two types of evolutionary pathways are possible depending upon how difficult (costly) it is to cope with the changes of the environment. In one case the population loses the learning ability, and the individuals inherit fixed synapses that are optimal in only one of the environmental states. In the other case a flexible subsystem emerges that allows the individuals to adapt to the changes of the environment. The model helps us to understand how an adaptive subsystem can emerge as the result of the tradeoff between the exploitation of a congenital structure and the exploration of the adaptive capabilities practised by learning. © 2002 Society for Mathematical Biology. Published by Elsevier Science Ltd. All rights reserved.
format JOUR
author Dopazo, H.
Gordon, M.B.
Perazzo, R.
Risau-Gusman, S.
spellingShingle Dopazo, H.
Gordon, M.B.
Perazzo, R.
Risau-Gusman, S.
A model for the emergence of adaptive subsystems
author_facet Dopazo, H.
Gordon, M.B.
Perazzo, R.
Risau-Gusman, S.
author_sort Dopazo, H.
title A model for the emergence of adaptive subsystems
title_short A model for the emergence of adaptive subsystems
title_full A model for the emergence of adaptive subsystems
title_fullStr A model for the emergence of adaptive subsystems
title_full_unstemmed A model for the emergence of adaptive subsystems
title_sort model for the emergence of adaptive subsystems
url http://hdl.handle.net/20.500.12110/paper_00928240_v65_n1_p27_Dopazo
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