Kashtan2005sem

<bibtex> @article{kashtan2005sem,

 title=Template:Spontaneous evolution of modularity and network motifs,
 author={Kashtan, N. and Alon, U.},
 journal={Proceedings of the National Academy of Sciences},
 volume={102},
 number={39},
 pages={13773--13778},
 year={2005},
 publisher={National Acad Sciences}

} </bibtex> link

This paper was fantastic, and makes me sad. They are demonstrating the point that I am trying to. But this is four years old and I just found it. How long before I stop being four years behind and start finding papers that are relevant to me as they come out?

This isn't how they say it, but they show that you can evolve modules by selecting for them. The way they did it was by changing the environment in a way that encourages the preservation of subparts of previous solutions. This is essentially multilevel selection. My hope is to apply multilevel selection to engineering and policy. They don't see either, or the potential of selection at higher scales to increase the complexity of evolved solutions. They evolve something that has been done, they don't seem to mention, or maybe realize, that they can use the same technique to evolve solutions to problems whose dimensionality is too high for normal selection. Of course, if I'm going to show that, I have to figure out how.

They mention "the field of evolutionary design of engineered systems". I wish. But they do cite Lipson.

Both they and Lipson (cited in the paper: with Pollack and Suh 2002) put too much emphasis on the changing environment, and not enough on the higher scale selection. These authors recognize that, but still attribute much to dynamic env. Too much? must think.

"Several studies suggested that duplication of subsystems(Calabretta, R. and Nolfi 1998) of selection for stability (Variano, E.A. and McCoy, J.H. and Lipson 2004) or robustness(thompson layzell 2000) can promote modularity"

"however, computer evolution simulations under randomly chaning environemnts do not seem to be sufficient to produce modularity (citing lipson)"

They use Newman for modularity metric

"In each experiment, the difference bewenn the perfect soluutions for the two goals differ by two connections. This small difference explains how the population can rapidly adapt when the goasl is switched"

Interestingly, they found more motifs in modular graphs, and controlled for artifacts of topology. It is due to the dynamics. I never liked motifs...

Evolving a modular circuit under a fixed goal "We find that modularity decreased rapidly within a few tens of gernerations provided there is even a slight selection pressure for small sircuit size"

never use the phrase 'multi-scale'

Missing the point: "Our results help explain how modules are maintained, because of their role in a changing environment" Modules are maintained by higher scale selection, which they implemented with a modularly changing environment.

<bibtex> @article{lipson2002omv,

 title=Template:On the origin of modular variation,
 author={Lipson, H. and Pollack, J.B. and Suh, N.P.},
 journal={Evolution},
 volume={56},
 number={8},
 pages={1549--1556},
 year={2002},
 publisher={BioOne}

} </bibtex> <bibtex> @conference{calabretta1998cse,

 title=Template:A case study of the evolution of modularity: towards a bridge between evolutionary biology, artificial life, neuro-and cognitive science,
 author={Calabretta, R. and Nolfi, S. and Parisi, D. and Wagner, G.P.},
 booktitle={Artificial Life VI, Proceedings of The Sixth International Conference on Artificial Life, MIT Press, Cambridge},
 year={1998}

} </bibtex> <bibtex> @article{variano2004nda,

 title=Template:Networks, dynamics, and modularity,
 author={Variano, E.A. and McCoy, J.H. and Lipson, H.},
 journal={Physical review letters},
 volume={92},
 number={18},
 pages={188701--188701},
 year={2004},
 publisher={APS}

} </bibtex> <bibtex> @conference{thompson2000ere,

 title=Template:Evolution of robustness in an electronics design,
 author={Thompson, A. and Layzell, P.},
 booktitle={Evolvable Systems: From Biology to Hardware: Third International Conference, ICES 2000, Edinburgh, Scotland, UK, April 17-19, 2000: Proceedings},
 pages={218},
 year={2000},
 organization={Springer}

} </bibtex>