Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!wuarchive!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!haven!adm!lhc!usenet From: usenet@nlm.nih.gov (usenet news poster) Newsgroups: comp.ai.neural-nets Subject: Re: Observations on the State of NN theory Message-ID: <1990Aug24.040330.6642@nlm.nih.gov> Date: 24 Aug 90 04:03:30 GMT References: <3430010@hpwrce.HP.COM> Reply-To: states@tech.NLM.NIH.GOV (David States) Organization: National Library of Medicine, Bethesda, Md. Lines: 51 kingsley@hpwrce.HP.COM (Kingsley Morse "km>") writes: states@tech.NLM.NIH.GOV (David States "ds>") writes ds> I am not aware of any evidence for genetic type algorithms actually ds> playing a role in biological learning. km> My understanding is that twin studies have shown that intelligence is km> inherited. (Twin studies measure twins who were separated at birth, to km> distinguish between inherited and environmental effects.) I'm assuming that km> if intelligence is inherited, then it's encoded in chromosomes, and thus km> operated on by GAs. The whole area of genetics and intelligence is highly contentious, to say the least. First, you should be aware that the "classic" studies on IQ and twins by Cyril Burt are now known to have been fabricated are a classic example of scientific fraud. Genetics determines the structure of a biological system. You are not a kangaroo because your development was not governed by a kangaroo's genes. Intelligence and learning, to me, imply adaptability, not a fixed structure. The fact that you sneeze when your nose is tickled may be genetically determined, but it is not evidence of intelligence. In the sense that humans are generally regarded as being more intelligent than kangaroos, I suppose it can be said that genetics has a role in determining intelligence. ds> Specifically, somatic cells, such as neurons, do not undergo ds> recombination. km> Can you be more specific? Do you mean that the components of individual km> cells don't undergo recombination? Do you mean that entire cells aren't km> recombined with other cells? What references are you using? Neurons are "somatic" cells meaning that they have lost the ability to undergo sexual division and that they cannot exchange genetic information. In the adult brain most neurons have lost the ability to divide altogether. Therefore, at least at the level of whole neurons or collections of neurons, there is no way to recombine optimal segments of previously trained data, the basis of a "genetic algortithm". See: SW Kuffler and JG Nicholls From Neuron to Brain Sinauer Associates, 1977 km> What was that "x" in your computational complexity table under km> the "Really Smart Systems" notestring? An arbitrary base for the exponent that is empirically determined so C = x^N implies that C grows exponentially with N but does not necessarily say how fast David States