August 30, 2008
Having come of age during the rise of the Internet, it's hard to imagine what it was like to do science back in the communication dark ages without tools like email, electronic journals, Wikipedia, etc. Most of my research has some component that requires quickly communicating with people over vast distances . This ease of interaction is all based on a few critical components of the Internet. First, the Internet is fast, in the sense that the Internet's routers and transmission lines allow information to get from A to B extremely quickly. Second, the Internet is navigable, meaning that A knows how to get to B using one of those quick routes. If either of these things failed, the Internet would quickly fall apart and people would go back to phoning and faxing each other . Yuck.
What's not widely known is that there's a real danger that the second of these two won't hold in the future. If so, trying to quickly reach Google, your humble blogger or anyone else may become as difficult as trying to drive from New York to Santa Fe without the help of a map or road signs. The problem is that the system that makes the Internet navigable is fundamentally flawed, and it's not clear how to fix it now that everyone depends so heavily on there being a working Internet. That is, we can't just turn the whole Internet off while we move everyone over to the new improved system.
One flaw is that the system wasn't designed to have the whole, or even a large fraction of the, world online. It was always thought that we would roll out a new series of tubes  down the road, but then something happened: the Internet became wildly popular, and that idea was ruined. A second flaw is that the system assumes everyone is always honest. The Internet's navigability comes from, basically, a massive but highly accurate game of telephone. In the children's version of this game, errors are introduced accidentally, and everyone laughs at the end about how strange the messages become. In the Internet version, a malicious person can introduce an error strategically, allowing them to eavesdrop on other messages (a la the NSA) or hijack messages before they reach their destination. It was recently demonstrated that these kinds of attacks are, in fact, relatively easy to do. We've been lucky so far that these kinds of attacks haven't been more widely used.
These and other issues make it very clear that the future of the Internet (and my scientific productivity!) depends on designing a more robust system, to which we can smoothly transition while still using the current broken version. But how exactly would a better system work? Earlier this summer, I coörganized a mini-workshop at SFI with some folks from CAIDA (Cooperative Association for Internet Data Analysis) based at UC San Diego about exactly this question. The attendees were primarily folks from the Internet-branch of the network science community, and the talks were focused heavily on alternative ways to make the Internet navigable. The result of the meeting was not a solution to the problem, but rather a set of questions that we think probably need to be answered before a real solution can be made.
 Usually, this is because my collaborators are remote; one of them I wrote two papers with before meeting him in person for the first time earlier this year.
 Increasingly phone calls depend on the same technology (packet switching) that runs the Internet, but originally, phone calls depended on a different kind of system (circuit switching), which guaranteed the delivery of information (i.e., no garbled conversations because of network congestion) but was significantly less flexible.
 This was a naive view, of course, but it's hard to make accurate predictions, especially about the future. The future was supposed to be based on something called IPv6, but if everyone used IPv6 today, it would break the Internet even faster. Fortunately, or unfortunately, almost no one uses IPv6 and it seems that no one is really planning to, either.
August 26, 2008
Cows are magnets.
Hot off the press at the Proceedings of the National Academy of Science is an article about magnetoreception in cows and deer . Begall and colleagues, perhaps having spent far too much time playing with Google Earth, noticed that grazing cows and deer  seem to slightly prefer aligning themselves N-S, like magnets in the Earth's magnetic field. From the abstract
To test the hypothesis that cattle orient their body axes along the field lines of the Earth's magnetic field, we analyzed the body orientation of cattle from localities with high magnetic declination. Here, magnetic north was a better predictor than geographic north. 
Time to rewrite the physics textbooks, I guess: Cows are spheres, yes, but magnetic spheres!
 S. Begall, J. Cerveny, J. Neef, O. Vojtech and H. Burda, "Magnetic alignment in grazing and resting cattle and deer." PNAS 105, 13451-13455 (2008).
 I was very disappointed, when I read through the article itself, to find no satellite pictures of cows aligned N-S. Indeed, there was not a single picture of a cow (or deer)!
 This is a good control to test the possibility that the E-W orientation of the sun drove the animals to prefer N-S in order to maximize the absorbed solar radiation. So, it seems that there really is some kind of weak magnetoreception going on. Now it's a matter of figuring out what biological compounds convey this magnetic sensitivity, and how its response to the Earth's field percolates up to behavioral tendencies.
August 20, 2008
Welcome to the club, Magpie (Pica pica)
The past 20 years have already been a humbling experience for people sympathetic to the idea that humans are unique among animals. For many years, it was thought that tool use was an exclusive trait of humans, but then the evidence rolled in that other primates routinely use tools. The real shocker, of course, is that some birds also use tools . And so it also went for cultural knowledge , long-term planning behavior, creativity, and dreaming. All of these behaviors are seen not just in other mammals, but in some species of birds. All this evidence makes it increasingly difficult to argue that there is much fundamentally special about Homo sapiens, except perhaps the coincidence of all of these behaviors in a single species.
To this list of human-like behaviors that birds exhibit, it seems we can now add self-recognition, at least for the European Magpie (Pica pica) . This idea is usually illustrated by the so-called mirror test : some kind of mark is placed on an animal in a spot they cannot normally see (on their chin, forehead, etc.), and a mirror is then placed so that they can see the mark on themselves. The usual interpretation of the resulting behavior is that if the animal recognizes themselves in the mirror, they will scratch directly at the foreign mark that they cannot normally see . This kind of mirror use is seen in all the great apes (humans older than 18 months, bonobos, chimpanzees, organutans and gorillas), dolphins, killer whales and elephants.
Of course, we still have no explanation of what allows such mirror-recognition to happen. Is it the size of the brain alone? (Probably not, but size is likely important in some ways.) Is there some special structure in the brain that mediates it? (Maybe. It would be interesting to stick some of these animals into a CT scanner while they're doing this test to see if there are homologous regions of the brain that light up.) Etc. One thing that's interesting about this new discovery of self-recognition in Magpies is that these birds are in the corvid family, which includes other clever birds like crows. This group of birds are fairly large, and thus have relatively large brains, so it may be that whatever neurological structures facilitate self-recognition, they require relatively large masses of neurons. From a more general perspective though, it's exciting that all of these "complex" behaviors appear in birds. Because their brains are structured quite differently from mammal brains, it suggests that there's not one single way to create "intelligent" brains. If it turns out that there are many many ways to create complex behavior, then perhaps one day we'll figure out what the essential structures and dynamics are, and be able to build one from scratch.
 This is pretty clearly a case of convergent evolution, since surely not all of the interceding species between birds and mammals were also tool users.
 H. Prior, A. Schwarz and O. Güntürkün, "Mirror-Induced Behavior in the Magpie (Pica pica): Evidence of Self Recognition." PLoS Biology 6, e202 (2008).
 The mirror test has, in fact, been heavily criticized for its indirectness and its bias toward human-style self-recognition. Of course, as anyone who's encountered the mind-numbing stupidity of corporate customer service, it can be extremely difficult to judge from behavior alone whether an animal is actually a thinking being. Examples abound of humans fooling ourselves and each other on this issue. If you ever want to experience this difficulty first-hand, try discussing with someone else whether your subjective experience of the world is similar or different from theirs.
 The control for this kind of experiment is to use two different color marks, one that is flesh- (or feather-)colored and one that is not.