It's a small world, after all

Posted 28 November 2005 by Tara Smith

Have you ever wondered how Kevin Bacon and the lights of fireflies related to malaria and power grids? I know it's something that's kept me up many a sleepless night. One word: interconnections. Many of you have probably heard of the "Six degrees of Kevin Bacon" game. This is based on the work of Stanley Milgram beginning in the 1960s, and brought up again more recently in a 1998 Nature paper, "Collective Dynamics of 'Small-World' Networks," by mathematicians Watts and Strogatz. Milgram conducted a number of studies using his "lost letter technique," in which letters were sent out and then needed to be forwarded onto reach their destination. In one instance, Milgram sent out 160 letters to individuals in the midwest, with instructions to pass them along to acquaintances who would be most likely to reach his stockbroker friend back east. Almost all of the letters that reached the stockbroker did so via one of 3 friends---and most did it within 6 steps--hence the "six degrees of separation" idea.

Similarly, Duncan Watts first became interested in the "small world problem"---the idea that all of us are more closely connected than we realize---after watching fireflies flash in synchrony, and wondering how they accomplished that. What Watts, Strogatz, Milgram, and others were investigating boiled down to a series of links in a network---hubs and connectors. As Watts and Strogatz showed in their 1998 paper, all it took to make a "small world" from a regular network was the addition of a few "short cuts" (see figure from their paper, right). This elegant and seemingly simple structure of networks explains not only connections between movie stars and scientists but also cellular metabolism, ecology webs and the World Wide Web itself. Continued at Aetiology

29 Comments

Barry Gibbons · 28 November 2005

Whatever

BWE · 28 November 2005

You just wanted to post a picture of Kevin Bacon. Admit it.

The article, using the shortcuts is alluding to the more important findings of the study which were that less than three people delivered all the letters to each individual. Meaning that our 6 degrees of separation are totally reliant on a few very well connected individuals. Read "the Tipping Point"
http://www.amazon.com/gp/product/0316346624/002-3054316-0638417?v=glance&n=283155&n=507846&s=books&v=glance

It's a good read. It is neat to see how it relates to biology in general though. It's some kind of emergent system a la sim city with the well connected individuals being the variable.

KeithB · 28 November 2005

Would Typhoid Mary be considered a Superspreader?

http://www.straightdope.com/mailbag/mtyphoidmary.html

theo · 28 November 2005

I don't understand the excitement about small-world and scale-free networks.

"There must be some deeper principle at work" is not exactly a unifying concept on the level of, say, natural selection. Frankly, it has the characteristic ring of physicists BSing about biology.

Here's the alternative: since mathematical tools for characterizing network topology are fairly crude, networks with many disparate causes (e.g. epidemiology and internet engineering) are mixed together under one "small-world" rubric. There are a plethora of reasonably effective generative models for small-world networks; this seems to confirm the hypothesis that they are an inappropriate overgeneralization.

Evelyn Fox Keller has an interesting critique of small-world networks, which should probably be read in conjunction with the books you recommend: http://www3.interscience.wiley.com/cgi-bin/abstract/112092785/ABSTRACT

BWE · 28 November 2005

RIght. 6 degrees of disease. Y'kmow, I bet the National center for disease control has some pretty good computer models for this stuff.

Tara Smith · 28 November 2005

You just wanted to post a picture of Kevin Bacon. Admit it.

:) That, and I played way too much of that game in college. theo, Thanks for the article. It seems she's criticizing most harshly the idea of a unifying law in all those systems, as you mention, as an inappropriate overgeneralization. And they indeed may be. But as a way to think about networks, and in my case, disease transmission, I think they're very helpful, and as indicated, provide real targets for intervention. And yes, Typhoid Mary could have been categorized as a "superspreader."

Steviepinhead · 28 November 2005

There may have been some unintended irony in your final phrase: "a rage of fields."

Heck, that finally explains some of the interactions that go on at PT!

The Ghost of Paley · 28 November 2005

Evelyn Fox Keller has an interesting critique of small-world networks, which should probably be read in conjunction with the books you recommend: http://www3.interscience.wiley.com/cgi-bin/abstr...

Cue Pacman death throes: whoooooooooooooo-quink!quink! Honestly, Tara, I thought that Dembski's butt-whuppin of Lilith would have cooled this hub-crap already, but I guess any port in a storm. Well, at least you're trying to lay a mathematical foundation for common descent; you recognise that the model of gene duplication + natural selection needs to be underwritten by more than sequence "homology" and just-so stories. Interesting article; needs more evolution in the future.

Tara Smith · 28 November 2005

There may have been some unintended irony in your final phrase: "a rage of fields." Heck, that finally explains some of the interactions that go on at PT!

Ha! That was *not* intentional. :)

Honestly, Tara, I thought that Dembski's butt-whuppin of Lilith would have cooled this hub-crap already, but I guess any port in a storm.

I'm not familiar with Dembski's "butt-whuppin" of anyone...more info, please?

Well, at least you're trying to lay a mathematical foundation for common descent; you recognise that the model of gene duplication + natural selection needs to be underwritten by more than sequence "homology" and just-so stories. Interesting article; needs more evolution in the future.

Well, no, that's not really what I'm trying to do at all. As I mentioned above, my main interest in it is how it relates to disease transmission; but studying it further, it also provides some instructive examples of how "complexity" or "design" can arise without a "designer."

BWE · 29 November 2005

Dembski's Butt-whuppin of Lilith is really a misinterpretation of historical data. "Lilly" was his mother and she often gave him "Butt whuppins" when ever he questioned her authority. This led him later in life to rationalize the dictates that didn't make sense of every authority figure he ran across for the rest of his life. His upholding of -creationism- ID is really his infantile fear of a "Butt-Whuppin" manifesting on a larger stage.

RBH · 29 November 2005

Ghost's reference may be to this ISCID thread. "Lilith" is Deanne Taylor, and her exchanges with Dembski start on p. 3 and continue for several pages, interspersed with another conversation involving Paul Nelson. I recommend reading the preceding posts for background on the exchange. I see no butt whipping of Deanne. This is the same thread in which Dembski agreed (on page 3, Sept 18 09:10 post) that cooption could produce IC structures and that ID provides no mechanistic account (i.e., no explanation, IMO) of phenomena:

I wrote, "Please show me in Michael Behe's writings or my own where we deny that IC systems can be made up of subsystems that can be functional in their own right." Both Behe and I have always defined IC with reference to the basic function of the system in question (if we've not said it explicitly -- and I have in NFL -- then a charitable reading would have granted that -- neither Behe nor I are that stupid). We therefore left open the possibility of subsystems having function in their own right. You and Yersinia charge us with a denial. The quotes you give indicate no such thing. As for your example, I'm not going to take the bait. You're asking me to play a game: "Provide as much detail in terms of possible causal mechanisms for your ID position as I do for my Darwinian position." ID is not a mechanistic theory, and it's not ID's task to match your pathetic level of detail in telling mechanistic stories. If ID is correct and an intelligence is responsible and indispensable for certain structures, then it makes no sense to try to ape your method of connecting the dots. True, there may be dots to be connected. But there may also be fundamental discontinuities, and with IC systems that is what ID is discovering.

yersinia's response of Sept 18, 12:22, seems appropriate. Dembski disappeared from the thread on page 6 (of 12). (ISCID URLs for individual posts don't work for old threads.) RBH

Tara Smith · 29 November 2005

Thanks! Good reference, and I hope Ghost was joking earlier...if that's a butt-whippin' by Dembski, I'm Mother Theresa.

'Rev Dr' Lenny Flank · 29 November 2005

I wrote, "Please show me in Michael Behe's writings or my own where we deny that IC systems can be made up of subsystems that can be functional in their own right." Both Behe and I have always defined IC with reference to the basic function of the system in question (if we've not said it explicitly --- and I have in NFL --- then a charitable reading would have granted that --- neither Behe nor I are that stupid). We therefore left open the possibility of subsystems having function in their own right.

I see. So a bacterial flagellum isn't a bacteria flagellum until, uh, it's . . . well . . a bacterial flagellum. Okaaaayyyyyyyyy. And where is the profound part of that conclusion . . . . . . ? No WONDER nobody takes ID seriously. (shrug)

The Ghost of Paley · 29 November 2005

Ghost's reference may be to this ISCID thread. "Lilith" is Deanne Taylor, and her exchanges with Dembski start on p. 3 and continue for several pages, interspersed with another conversation involving Paul Nelson. I recommend reading the preceding posts for background on the exchange. I see no butt whipping of Deanne.
— RBH

Why am I not surprised? In your defense, Dembski's courtliness and natural modesty hid the magnitude of the carnage for those blinded by Darwin (as opposed to science). The Wizard bagged his quarry at the very beginning:

The Wizard: As with so much of the self-organizational literature that I've seen applied to biology, I see in your post the attempt to make some global property make all the pieces suddenly fall into place and all the problems disappear. You write: "The QUALITY of the network, the very essence of the biological network, speaks to the very same mechanism you are demanding proof of." How does a "quality" that "speaks to" some mechanism explain anything or provide a proof? I asked for a detailed Darwinian pathway for IC systems, not a feature that biological systems should have if the Darwinian mechanism is taken for granted as having the power to produce IC systems. And it seems to me that's all you're doing. Again you write: "In the case of biological networks, there is a footprint laid down in the very qualities of these networks, furnished by scale invariance, that points to the source of that scale invariance in simpler progenitor networks." Okay, so there are some footprints that these networks that exhibit scale invariance leave behind (let's grant that all these concepts are well-defined). What of it? These are just words. Where are the bridge principles that connect these concepts to actual biological systems and provide concrete insights into the nuts and bolts of IC systems? Or consider: " I argue scale-free invariance in networks is the smoking-gun evidence for exactly what you're asking for." But where's the argument? Where's the causal specificity? It's all fine and well to model an evolutionary process computationally and get hierarchical systems exhibiting scale invariance. But scale invariance is a global property that can be modeled without ever introducing irreducible complexity (indeed, the work you cite has proceeded quite nicely without Behe). IC is a local property. That's why it needs to be assessed system by system. [my emphasis]

Compare this to:

Recent observations of power-law distributions in the connectivity of complex networks came as a big surprise to researchers steeped in the tradition of random networks. Even more surprising was the discovery that power-law distributions also characterize many biological and social networks. Many attributed a deep significance to this fact, inferring a universal architecture of complex systems. Closer examination, however, challenges the assumptions that (1) such distributions are special and (2) they signify a common architecture, independent of the system's specifics. The real surprise, if any, is that power-law distributions are easy to generate, and by a variety of mechanisms.

Lilith should get a new tattoo: "Property of The Wizard".

'Rev Dr' Lenny Flank · 29 November 2005

Dembski's courtliness and natural modesty

BWA HA HA HA HA HA HA !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Good one, Isaac. If Dembski is so devestating, of course, one wonders why he didn't have the cajones that Behe had to get on the witness stand in Dover.

'Rev Dr' Lenny Flank · 29 November 2005

hid the magnitude of the carnage for those blinded by Darwin (as opposed to science).

Waterloo !!!! Waterloo !!!!! Waterloo !!!!!!! (yawn) What, again, did you say the alternative scientific theory is that ID offers? Oh, that's right --- you DIDN'T say, did you. I wonder why that would be . . . . . . .

The Ghost of Paley · 30 November 2005

Waterloo !!!! Waterloo !!!!! Waterloo !!!!!!! (yawn)
— Reverend Jim

Bored by your own posts? Let the punishment fit the crime.

What, again, did you say the alternative scientific theory is that ID offers? Oh, that's right ---- you DIDN'T say, did you. I wonder why that would be ... ... .
— Reverend Jim

Let's see....Dembski's got new monographs out, Mike Gene is using I.D. to derive predictions of hook gene function, I.D. scientists are discovering roles for "junk" DNA, I'm currently challenging geocentric dogma with my exciting new model.....it's great to be a creationist nowadays. Never thought someone who call ya on yer bullplop, didya? Got anything to add to the debate or not?

Steviepinhead · 30 November 2005

Links to back up any of these claims, pal?

I mean, of course, the ones that you contend actually propose a theory of ID, a mechanism, testible hypotheses? Don't bother to link to the gobbledygook that simply says--at much more tedious length--things to the effect of, "Gosh! That sure looks designed--and I really wish and hope that it were designed--so therefore it must be designed!"

'Rev Dr' Lenny Flank · 30 November 2005

Got anything to add to the debate or not?

Nope. And neither do you. Until IDers provide, well, a scientific theory of ID, there simply *IS* nothing to "debate". (shrug) Got one? Why not?

'Rev Dr' Lenny Flank · 30 November 2005

.it's great to be a creationist nowadays.

Um, I thought IDers weren't creationists. Make up your friggin mind, would you?

The Ghost of Paley · 30 November 2005

Links to back up any of these claims, pal?
— Queen Pinhead

Dembski's new stuff. Mike Gene's Prediction. Evo Bunko in the Junk-O.

Nope. And neither do you. Until IDers provide, well, a scientific theory of ID, there simply *IS* nothing to "debate". (shrug) Got one? Why not?
— Reverend Jim

See my heliocentric-bashing paper in "After the Bar Closes", Chief.

Steviepinhead · 30 November 2005

Couldn't be bothered to set forth the theory, the mechanism, and the hypotheses, could you, ghosty?

(shrug)

One of Dembski's pdf's never loaded: blank pages (but presumably no net loss of information, heh heh).

The other pdf is just the old Dembski razzle-dazzle: extremely unlikely things are extremely unlikely. Irrelevant to evolution, since evolution is not a random procedure. None of the prior criticisms of his work are addressed. Further (and this also applies to the laughable Luskin), no mechanism whereby intelligent agents are able to make untenable leaps in information "space" is presented. If intelligence didn't evolve, where did it come from? How does "intelligence" generate novel, exceedingly-unlikely solutions?

It doesn't look like your other friend quite understands what a frameshift is, and isn't. In any event, no ID mechanism for generating one is set forth, which brings us back to the top of this comment: until you've got a theory, a mechanism, and some testible hypotheses, ya got nuttin'.

'Rev Dr' Lenny Flank · 30 November 2005

See my heliocentric-bashing paper in "After the Bar Closes", Chief.

I, uh, don't see any scientific theory of ID there, Honcho. Why not?

The Ghost of Paley · 30 November 2005

By the way, I think the people on this board are overly infatuated with mechanism-driven hypotheses. Since design is a state variable, it exists independent of any path of creation. The scientist must first establish the existence of the phenomenon under study, then worry about cause. I think that Dembski has achieved the first goal. Unfortunately, the intellectual death created by the poisoned Kool-Aid of Darwin's Folly prevents the cultists from acknowledging this simple fact, leading to the ludricrous demands seen here.

Steviepinhead · 30 November 2005

Even if we were willing to let you slide on a mechanism, a theory and some hypotheses would also be nice. You seem to like to pick and choose what you want to deal with. That's okay, we simply presume that what you don't want to respond to is what you simply can't respond to.

And what we're really enamoured of on this board is evidence.

Got any?

Didn't think so (shrug).

The Ghost of Paley · 30 November 2005

One of Dembski's pdf's never loaded: blank pages (but presumably no net loss of information, heh heh). The other pdf is just the old Dembski razzle-dazzle: extremely unlikely things are extremely unlikely. Irrelevant to evolution, since evolution is not a random procedure. None of the prior criticisms of his work are addressed.
— Pinhead

Both links work fine for me; of course, most people don't use their VIC-20's anymore, having thrown them away with the Goldfish Platforms and cokespoons, the last getting heavy rotation, apparently, judging by the content of your posts. And Dembski does incorporate natural selection into his model; see the abstract to the first cited paper.

How does "intelligence" generate novel, exceedingly-unlikely solutions?
— Pinhead

I'm working on this, not that it's necessary. See my previous post.

I, uh, don't see any scientific theory of ID there, Honcho. Why not?
— Reverend Jim

Well, first you'd have to find a cheerleader to read it to you.

k.e. · 30 November 2005

Once again The Ghost of Paley creates/projects/found 'God' in his own image pick from any of these

"
VIC-20's anymore, having thrown them away with the Goldfish Platforms and cokespoons the last getting heavy rotation,, apparently, judging by the content of your posts. And Dembski does incorporate natural selection into his model; see the abstract to the first cited paper.
"

k.e. · 30 November 2005

What is it with you ghosty they won't let you ?

take a look at this

"The Large Glass" by Marcel Duchamps

Tara Smith · 1 December 2005

Okay, that's enough of that. Maybe next time we can do it without all the sniping.