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August 30, 2007

WNYC on emergence

Radio station WNYC did a 60 minute segment on "emergence" by Jad Abumrad (of WNYC) and Robert Krulwich (of NPR's Science Desk) which is quite well done. Well worth a listen.

The segment features many of the usual suspects. Steve Strogatz talks about firefly synchronization (for instance, did you know that fireflies in Thailand gather in thousands and lightup in time with each other). Deborah Gordon talks about the wildly complex behavior of large groups of ants as compared to the stupid behavior of single ants. Steven Johnson, author Emergence, features several times. And my colleague Iain Couzin makes an appearance to talk about collective behavior. Toward the end, Christof Koch makes an appearance to talk about his collaboration with Francis Crick to figure out how consciousness works. Quite a cast, and Jad does an excellent job of weaving the clips and segments into a compelling whole.

Throughout the piece, there is the consistent theme that the behavior of some systems seems to be more than just the sum of the parts, at least from the typical reductionist perspective that's served science so well in other areas. Ants and brain cells are examples of things that, by themselves, are pretty dumb, but when put together in large numbers, groups of them can acheive complex behavior that often seems highly intelligent. The fundamental question is, How do they do it? Scientists want to know because many of life's complexities (like your brain) are clearly examples of "emergent complexity" and engineers want to know because systems that are emergently complex seem to have other features that we'd like to build into our machines. Characteristics like robustness to failures, adaptability, etc. (Familiar themes, for sure.)

I suspect that physicists are right when they say that emergence has a lot to do with phase transitions, but I think there's more to it than just that. It's probably partly my own biases and training to believe that emergence has a lot to do with computation (of the distributed sort), and thus that computer science is likely to have a great deal to offer. That's the idea at least, and so far, so good.

posted August 30, 2007 04:24 PM in Complex Systems | permalink | Comments (2)

August 28, 2007


(via PhD Comics)

posted August 28, 2007 10:23 AM in Humor | permalink | Comments (0)

August 25, 2007

Clever, clever bird

Those clever clever crows. Not only can they use pieces of wire as tools to get food they want, but they can use pieces of wire to get other pieces of wire to get food they want! And what is this behavior called? Meta-tool use, obviously.

This fact makes me more convinced than ever that after we humans wipe ourselves out, crows are going to take over as the dominant species on the planet... forget Planet of the Apes, it's going to be Planet of the Crows. (via NewScientist)

A. H. Taylor, G. R. Hunt, J. C. Holzhaider and R. D. Gray, Spontaneous Metatool Use by New Caledonian Crows, Current Biology in press (2007).

p.s. In other news, I quite like the two recent studies that appeared in Science last week showing that researchers can induce out-of-body experiences in normal people using a trick of virtual reality (via Nature News and NYTimes. The scientific conclusion is that these experiences are some kind of hallucination of the mind, brought on by a confusing set of sensory inputs or a misprocessing of existing inputs (or both), and not evidence of a soul or anything supernatural. They have yet to explain why this kind of confusion often happens during brain death, but we'll have to wait for a fortuitous stroke or tumor to figure that out.

posted August 25, 2007 02:53 PM in Obsession with birds | permalink | Comments (0)

August 22, 2007

Seam carving and image resizing

This technique for image resizing (which appeared in SIGGRAPH 2007) is extremely cool. I particularly like the erasure feature - that could come in handy for removing former friends or ex-girlfriends from favorite photos. I predict it will also usher in a whole new era of crafty image manipulation for political reasons... politicos can just erase themselves from the incriminating photos!

In the paper (reference given below), the authors note that the seam carving method for removing (or adding) pixels performs poorly when there aren't many places with "low content" and describe an example with human faces. These sensitive areas can be protected (forcing the seams to avoid them), but there are limits as to how much carving can be done when there are a lot of places that you want to protect. All in all, an impressively clever approach to image resizing.

S. Avidan and A. Shamir, "Seam Carving for Content-Aware Image Resizing." SIGGRAPH (2007). [Warning: pdf is about 21MB in size; alternative source (via ACM).]

Update 1 February 2008: The New York Times is now (finally) running an article on popular versions of this technique, and its implications for photo art. (Tip to Jake)

posted August 22, 2007 08:45 AM in Computer Science | permalink | Comments (0)

August 21, 2007

Sleight of mind

There's a nice article in the NYTimes right now that ostensibly discusses the science of magic, or rather, the science of consciousness and how magicians can engineer false assumptions through their understanding of it. Some of the usual suspects make appearances, including Teller (of Penn and Teller), Daniel Dennett (that rascally Tufts philosopher who has been in the news much of late over his support of atheism and criticism of religion) and Irene Pepperberg, whose African parrot Alex has graced this blog before (here and here). Interestingly, the article points out a potentially distant forerunner of Alex named Clever Hans, a horse who learned not arithmetic, but his trainer's unconscious suggestions about what the right answers were (which sounds like pretty intelligent behavior to me, honestly). Another of the usual suspects is the wonderful video that, with the proper instruction to viewers, conceals a person in a gorilla suit walking across the screen.

The article is a pleasant and short read, but what surprised me the most is that philosophers are, apparently, still arguing over whether consciousness is a purely physical phenomenon or does it have some additional immaterial component, called "qualia". Dennett, naturally, has the best line about this.

One evening out on the Strip, I spotted Daniel Dennett, the Tufts University philosopher, hurrying along the sidewalk across from the Mirage, which has its own tropical rain forest and volcano. The marquees were flashing and the air-conditioners roaring — Las Vegas stomping its carbon footprint with jackboots in the Nevada sand. I asked him if he was enjoying the qualia. “You really know how to hurt a guy,” he replied.

For years Dr. Dennett has argued that qualia, in the airy way they have been defined in philosophy, are illusory. In his book “Consciousness Explained,” he posed a thought experiment involving a wine-tasting machine. Pour a sample into the funnel and an array of electronic sensors would analyze the chemical content, refer to a database and finally type out its conclusion: “a flamboyant and velvety Pinot, though lacking in stamina.”

If the hardware and software could be made sophisticated enough, there would be no functional difference, Dr. Dennett suggested, between a human oenophile and the machine. So where inside the circuitry are the ineffable qualia?

This argument is just a slightly different version of the well-worn Chinese room thought experiment proposed by John Searle. Searle's goal was to undermine the idea that the wine-tasting machine was actually equivalent to an oenophile (so-called "strong" artificial intelligence), but I think his argument actually shows that the whole notion of "intelligence" is highly problematic. In other words, one could argue that the wine-tasting machine as a whole (just like a human being as a whole) is "intelligent", but the distinction between intelligence and non-intelligences becomes less and less clear as one considers poorer and poorer versions of the machine, e.g., if we start mucking around with its internal program, so that it makes mistakes with some regularity. The root of this debate, which I think has been well-understood by critics of artificial intelligence for many years, is that humans are inherently egotistical beings, and we like feeling that we are special in some way that other beings (e.g., a horse or a parrot) are not. So, when pressed to define intelligence scientifically, we continue to move the goal posts to make sure that humans are always a little more special than everything else, animal or machine.

In the end, I have to side with Alan Turing, who basically said that intelligence is as intelligences does. I'm perfectly happy to dole out the term "intelligence" to all manner of things or creatures to various degrees. In fact, I'm pretty sure that we'll eventually (assuming that we don't kill ourselves off as a species, in the meantime) construct an artificial intelligence that is, for all intents and purposes, more intelligent than a human, if only because it won't have the enumerable quirks and idiosyncrasies (e.g., optical illusions and humans' difficulty in predicting what will make us the happiest) in human intelligence that are there because we are evolved beings rather than designed beings.

posted August 21, 2007 09:52 AM in Thinking Aloud | permalink | Comments (22)

August 18, 2007

WikiScanner reveals biased edits of Wikipedia

I met Virgil Griffith, a graduate student at CalTech in cognitive science (but also a skilled computer hacker), earlier this year while he was visiting SFI to work with Eric Smith and Doyne Farmer.

Virgil's gotten himself quite a bit of coverage over a simple piece of software he wrote (apparently at least partially while he was at SFI) called WikiScanner that simply pushes the IP addresses of the editors of a particular wikipedia page against things like the the WHOIS database (for example, here) and a geolocation algorithm for IP address (such as ip2location.com) to find out whether certain, achem, interested parties are editing certain pages related to their interests. Predictably, many corporations, from PepsiCo to ExxonMobile to FoxNews, have removed portions (typically the unfavorable bits) of the wikipedia articles about themselves.

Well done, Virgil, well done.

I think Wired wrote the first story, but there's now an ABC news story and a NYTimes story, too.

posted August 18, 2007 08:40 PM in Political Wonk | permalink | Comments (0)

August 16, 2007

Announcement: IPAM Social Data Mining and Knowledge Building Workshop

This sounds interesting. Also, Andrew McCallum is a very smart guy.

Institute for Pure and Applied Mathematics (IPAM; UCLA) Social Data Mining and Knowledge Building

November 5 - 9, 2007 at IPAM, UCLA, Los Angeles

Organizers: Peter Jones (Yale), Johan Bollen (LANL), Ronald Coifman (Yale), Andrew McCallum (UMass-Amherst), and Karin Verspoor (LANL).

Description: Social Data Mining is a fast-growing and exciting area of inquiry, in which connections among and interactions between individuals are analyzed to understand innovation, collective decision making, and problem solving, and how the structure of organizations and social networks impacts these processes. Analysis of such inherently relational datasets is currently being applied in e-commerce to drive recommendation systems, in bibliometrics to describe patterns of publication and determine the influence of specific individuals, in security environments to understand the structure of terrorist or gang networks, and numerous other areas. This workshop will bring together researchers in mathematics, computer science, and the social sciences to explore the following topics:

  • collective decision making
  • social network analysis
  • social mapping and bibliometrics
  • the role of information visualization in understanding social networks
  • the application of graph-theoretical analysis to social networks
  • data representation strategies, e.g. the Semantic Web

posted August 16, 2007 12:48 PM in Conferences and Workshops | permalink | Comments (0)

August 14, 2007

Douglas Adams on the scientific method

I recently finally got around to reading Douglas Adams' Dirk Gently's Holistic Detective Agency, and thoroughly enjoyed it. I especially liked the bit about the horse. In addition to being a very clever writer, Adams was a passionate supporter of sense and rationality. At a 1998 conference at Cambridge, he gave an impromptu speech about religion and science. Here's an excerpt.

Now, the invention of the scientific method and science is, I'm sure we'll all agree, the most powerful intellectual idea, the most powerful framework for thinking and investigating and understanding and challenging the world around us that there is, and that it rests on the premise that any idea is there to be attacked and if it withstands the attack then it lives to fight another day and if it doesn't withstand the attack then down it goes. Religion doesn't seem to work like that; it has certain ideas at the heart of it which we call sacred or holy or whatever. That's an idea we're so familiar with, whether we subscribe to it or not, that it's kind of odd to think what it actually means, because really what it means is 'Here is an idea or a notion that you're not allowed to say anything bad about; you're just not. Why not? - because you're not!' If somebody votes for a party that you don't agree with, you're free to argue about it as much as you like; everybody will have an argument but nobody feels aggrieved by it. If somebody thinks taxes should go up or down you are free to have an argument about it, but on the other hand if somebody says 'I mustn't move a light switch on a Saturday', you say, 'Fine, I respect that'. The odd thing is, even as I am saying that I am thinking 'Is there an Orthodox Jew here who is going to be offended by the fact that I just said that?' but I wouldn't have thought 'Maybe there's somebody from the left wing or somebody from the right wing or somebody who subscribes to this view or the other in economics' when I was making the other points. I just think 'Fine, we have different opinions'. But, the moment I say something that has something to do with somebody's (I'm going to stick my neck out here and say irrational) beliefs, then we all become terribly protective and terribly defensive and say 'No, we don't attack that; that's an irrational belief but no, we respect it'.

If you enjoyed that, there's a clip at onegoodmove.org with Richard Dawkins reading a portion of the larger speech from which the above excerpt comes.

posted August 14, 2007 11:12 AM in Political Wonk | permalink | Comments (0)

August 13, 2007

Things to read while the simulator runs; part 6

Back from a relaxing but oppressively humid vacation on the South Carolina shore, I've missed a lot of interesting science news. Someone asked me recently if I literally read the things I blog about while I let my simulators run. The answer is... well, sometimes. It's true that I do spend both a lot of time reading and a lot of time simulating things, so naturally there will be a lot of overlap between the two activities. Anyway, here is a list of some interesting stories I missed over the past week.

Nanotubes plus paper make for flexible batteries. (Nature News; also via Ars Technica here)

Slightly helpful mutations in E. coli much more plentiful than thought. (Nature News)

Year-round schools don't boost learning (Science Blog)

X-ray images help explain limits to insect body size (Science Blog)

Baby DVDs may make kids dumb (Science Blog; also via Ars Technica here)

Fat is the new normal (Science Blog)

Homeland Security tests automated "Hostile Intent" detector (Ars Technica)

Big Media losing grip thanks to the Internet and America's political divide (Ars Technica)

The religious state of Islamic science (Salon)

Single amino acid change turns West Nile Virus into a killer (Ars Technica Science)

Watching the heat flow through a molecule (Ars Technica Science)

President Bush signs law boosting science funding (Ars Technica Science)

Speciation and the transcription factor shuffle (Ars Technica Science)

posted August 13, 2007 05:17 PM in Things to Read | permalink | Comments (0)

August 04, 2007

Milgram's other experiment

In my line of work, Stanley Milgram is best remembered for his small-world experiment. But in other circles, he's better known for his work on human obedience. This seminal study was done back when scientific brilliance was unfettered by pesky rules about ethics, but thanks to the wonders of YouTube, you can share in his joyous discovery of how presumably good, or maybe at least "normal" (whatever that means), people can be made to do thing they know to be terrible when instructed by a superior. (In fact, it is partially because of this experiment that science now has an internal review mechanism to prevent such psychologically traumatic experiments from being conducted.) Here is Milgram writing in his 1974 article "The Perils of Obedience" (reproduced here) on the results of his study:

The legal and philosophic aspects of obedience are of enormous importance, but they say very little about how most people behave in concrete situations. I set up a simple experiment at Yale University to test how much pain an ordinary citizen would inflict on another person simply because he was ordered to by an experimental scientist. Stark authority was pitted against the subjects' [participants'] strongest moral imperatives against hurting others, and, with the subjects' [participants'] ears ringing with the screams of the victims, authority won more often than not. The extreme willingness of adults to go to almost any lengths on the command of an authority constitutes the chief finding of the study and the fact most urgently demanding explanation.

posted August 4, 2007 04:04 PM in Scientifically Speaking | permalink | Comments (2)

August 03, 2007

Announcement: Workshop on Theoretical Aspects and Models of Large Complex and Open Information Networks

I recently received an invitation to speak at this workshop; my intention is to attend, but this kind of depends on whether the US Government can get me my new passport in time. Regular readers will recall that back in April I suffered the unspeakable tragedy of having my laptop (and bag, with contents) stolen. For a completely stupid reason, my passport was in the bag, and I only just recently got around to sending off the application for a replacement. I must admit, I'm extremely excited about getting a new RFID-enabled passport though. Just think about all the time I could save in customs if officials could scan my passport from a distance!

Anyway, on to the real business of this post...

The Institute for Scientific Interchange (ISI; in Torino, Italy) Workshop on Theoretical Aspects and Models of Large Complex and Open Information Networks

November 19 - 21, 2007 at the ISI Foundation, Villa Gualino, Torino Italy

Organizers: Allain Barrat (Paris-Sud and ISI), Josep Diaz (Universitat Politecnica de Catalunya), Lefteris Kirousis (Computer Technology Institute, Patras, Greece), and Alessandro Vespignani (Indiana U. and ISI).

Description: Large, Complex and Open Information Networks consist of many interacting nodes, and have been shown to possess emerging properties such as the small-world character or the widespread heterogeneity of the connectivity.

Research in network theory includes many different aspects. New tools have been developed for the analysis and description of the topology of networks. New models have aimed at understanding how self-organization is realized and how local decisions concerning connectivity among nodes affect the global emergent properties of such networks, like percolation, clustering, critical exponents etc.
Moreover, complex networks are most often the substrate of many dynamical process that can be of critical importance. For example, biological networks carry out vital functions, the Internet is the support of many different information transfer networks, while social networks are the environment in which epidemics, rumors, fads or opinions propagate. Finally, attention has been recently been devoted to the dynamical nature of networks, whose topology can be influenced by the dynamical process of which it is the support.

The scope of this workshop is to foster interaction among researchers interested in these various aspects of network science, and to encourage interdisciplinary approaches (for example, from the point of view of complex systems, computer science, statistical mechanics, discrete mathematics, biology and others).

posted August 3, 2007 02:36 PM in Conferences and Workshops | permalink | Comments (0)

August 02, 2007

An extension of the brief hiatus

Last week I returned from the Boulder School on Biophysics, which was a fascinating experience in which I learned all sorts of stuff about the way physicists operate in and think about biology. (For instance, they're most comfortable when talking about things like single-molecule dynamics, where the forces are clear, or simple diffusion or stochastic processes.) One reassuring behavior I observed was that biophysicists get just as unmoored when they don't have "first principles" to work from as I feel sometimes working on networks and complex systems in general. Another interesting thing I learned is that machine learning techniques aren't very well known among experimental or theoretical biophysicists, but that among the younger folk, there was a great deal of interest in using computation to extract meaningful things from data.

I also became familiar with two wonderful quotations. The first is from Lord Rutherford, who supposedly said "If your experiment needs statistics, you ought to have done a better experiment." I can imagine that this statement was uttered in a slight growl; of course, the deep irony is that his intellectual descendents, the high energy physicists, are perhaps some of the best statisticians in physics! (For instance, see this excellent entry by John over at Cosmic Variance about bump hunting in data.) The second is from 'Rosencrantz and Gildenstern are Dead' (imdb), which goes "Audiences know what they expect and that is all they are prepared to believe in."

Anyway, this week I've been furiously trying to get some work I did over the last two weeks of the summer school into the form of a paper. Needless to say, this has consumed most of my time this week, hence the lack of blogorific prose. Next week, I'll be completely offline, frolicking in the surf in South Carolina. Then, it's back to the grind stone of producing bloggable events and thoughts...

posted August 2, 2007 02:59 AM in Blog Maintenance | permalink | Comments (0)