Saturday, January 24, 2004
The Secret Inner Computational Lives of Plants
I have maintained for a long time that the intelligence of plants is severely underappreciated. This is, among other things, why I am not a vegetarian --- I don't see much moral difference between using cows for food and using wheat for food. A stalk of wheat may have "consciousness" that is more alien to us than that of a cow, but it may be no less worthy of consideration.
Well, progress is being made on this front. Three-Toed Sloth points to a recent paper by D. Peak, J. D. West, S. M. Messinger, and K. A. Mott with this fascinating abstract:
It has been suggested that some biological processes are equivalent to computation, but quantitative evidence for that view is weak. Plants must solve the problem of adjusting stomatal apertures to allow sufficient CO2 uptake for photosynthesis while preventing excessive water loss. Under some conditions, stomatal apertures become synchronized into patches that exhibit richly complicated dynamics, similar to behaviors found in cellular automata that perform computational tasks. Using sequences of chlorophyll fluorescence images from leaves of Xanthium strumarium L. (cocklebur), we quantified spatial and temporal correlations in stomatal dynamics. Our values are statistically indistinguishable from those of the same correlations found in the dynamics of automata that compute. These results are consistent with the proposition that a plant solves its optimal gas exchange problem through an emergent, distributed computation performed by its leaves.
I, for one, welcome our new photosynthetic overlords.
Friday, January 23, 2004
Pop quiz: What is the rate of mistaken paternity?
Everyone knows that men can never really know that their children are biologically their own, short of a DNA test. But most people think that, well, cases of mistaken paternity are rare freak cases, and the people we know couldn't possibly be cases of mistaken paternity; and most men figure that when they have kids, of course the woman they choose will be trustworthy and faithful, so it's a problem for freak-show losers to worry about.
Heh.
While reading Gigerenzer's Law of Indispensable Ignorance on Edge.org's Edge Annual Question (this year, "What's Your Law?"), I came across the startling sentence:
The estimated 5 to 10% of children and their fathers who falsely believe that they are related might not lead a happier life by becoming less ignorant; knowledge can destroy families.
"Holy crap! 5-10%? That's got to be a mistake," I thought. Is it? Like any lazy researcher, I did a quick Google search, which turns up a thread from the sci.anthropology newsgroup archives with the rather insensitive, albeit humorous, subject "How many bastards are there, anyway?". At first, it seems, we can breathe a sigh of relief, as Lee Rudolph writes:
Yesterday I was talking to a bioethicist who studies genetic counseling, and when the conversation turned to folklore, she brought up an issue she'd recently investigated. She told me that essentially all genetic counselors believe that there is a "false paternity" rate of about 5 percent--yet few if any counselors encounter a rate nearly that high in their own practices. This discrepancy having piqued her curiosity, my friend had tried to track down just why the rate is believed to be 5 percent. One source after another said the scientific equivalent of "it was published by a friend of a friend". Eventually the FOAF-chain terminated, in a single paper whose author does not think it supports the interpretation it is popularly given! Appendix 1, immediately below, represents the present state of her research into this possible piece of genetic folklore.
... [skipping to appendix] ...
A historical search and a conversation with Dr. James Neel, one of the deans of human genetics, led us to what may be the source for the high estimate: a 1962-65 study of blood typing in a small Michigan town (1). That study found discrepancies between biological and stated parentage in 109 of 2507 nuclear familes. Many of these may have been unacknowledged adoptions, including step-parent adoptions.
...[skipping to cite]...
(1) Sing, CF et al (1971) Studies on genetic selection in a completely ascertained Caucasian population II. Family analysis of 11 blood group systems. American Journal of Human Genetics 23(2) 164-198.
Whew! OK, so it's one small study, and it may not have counted adoptions properly. But hold on --- a few messages later in the thread, Joe Quellen writes:
The statistics are covered in a very engrossing book by Jared DIamond, called *The Third Chimpanzee*, 1992, Harper Perennial, Chapter 4, The Science of Adultery. He describes a study of blood typing and genetics which had unexected results and was quashed. It was done in the 1940s at a "highly respectable" US hospital. The study found that fully 10 percent of babies were not the biological offspring of their legal fathers.
Oh. Diamond was citing a different study. A couple of messages later, "sgf" writes:
I just picked up Timothy Taylor's _The Prehistory of Sex: Four Million Years of Human Sexual Culture_ (Bantam: 1996). Here's his summarization of the subject:
(pp 77-79)
"...In tests of genetic paternity recently conducted by Robin Baker and Mark Bellis [1], they found that around 10 percent of children had been sired by someone other than their ostensible fathers -- although the fathers consciously believed these children to be their own....[skipping to cite]...
[1 Baker, R. and M. Bellis. 1993 "Human sperm competition: ejaculate adjustment by males and the function of masturbation." _Animal Behaviour_ 46: 861-65]
And just to pile on a bit, the next Google hit is a working paper by anthropologist Kermyt G. Anderson titled "How well does paternity confidence match actual paternity? Evidence from worldwide nonpaternity rates" (abstract), wherein we learn:
The median nonpaternity rate for the high paternity confidence sample is 1.9% (range: 0.4 - 11.8), while median nonpaternity for the low paternity confidence sample is 30.2% (range: 14.3 - 55.6). The median nonpaternity rates for these two groups are significantly different (Wilcoxon sign-rank test, z = -6.112, p < 0.0001), which is not surprising since the two distributions do not even overlap. Thus, men with high paternity confidence are less likely to be incorrect in their assessment of paternity than men with low paternity confidence. In other words, men with high paternity confidence are more accurate in assessing paternity.
The median nonpaternity of men whose paternity confidence is unknown is 16.7% (range: 2 - 32). This is significantly greater than the high paternity confidence sample (Wilcoxon sign-rank test, z = -4.349, p < 0.0001), and significantly lower than the low paternity confidence sample (Wilcoxon sign- rank test, z = 3.528, p = 0.0004).
When the high and unknown paternity confidence samples are combined, the median nonpaternity is 3.9% (range: 0.4 R 32). This is significantly less than median nonpaternity for men with low paternity confidence (Wilcoxon sign-rank test, z = -6.053, p < 0.0001). Thus, men with low paternity confidence are the least accurate in assessing actual paternity.
In other words, interpreting the results rather cavalierly, if you're fairly confident that the child is yours, it is probably yours (although, interestingly, nearly 1 out of 50 such men are still mistaken). If you've got suspicions, then the probability that it's not yours is nearly one out of three. Intuitively, this makes sense: men don't just doubt for no reason. If you have reason to doubt, then it's probably with some justification.
Anyway, the 5-10% number seems to be a bit of an overestimate; the actual number from the most comprehensive survey seems to be in the 2-4% range. Still disturbingly high, in my opinion.
Bookmarks cleaning
Ask Metafilter: Idiot's guide to Indian food
What kind of asshole would vandalize Sadako?
One of the few real complaints I have about Emacs is that it often interacts weirdly with cut and paste under X. Jamie Zawinski explains why.
Kitty go potty? Good kitty.
Shriram Krishnamurthi has a new programming languages textbook linked from his homepage. It's excellent.
Fedora Linux is excellent, but up2date and yum often don't work quite right due to the heavy load on Red Hat's servers. This post explains how to point your up2date at one of the mirrors; also, here's how to add mozilla to your channels.
A novel approach to gun control
Boy wonder hacker extraordinaire Aaron Swartz writes, in Lawrence Lessig's blog comments:
On a different note, I’ve never understood the reasoning that causes libertarians to think that restrictions on personal freedom, when called “property” (or something similar), not only become OK but something to be championed. I can see why a principled libertarian might conclude that “what’s mine is mine and what’s yours is yours” is the best way to protect personal freedom, but it seems awfully bizarre to attack something like “increasing fair use”, since I can’t think of any reason such increases could hurt the freedom of authors.
To get away from the First Amendment, try this hypothetical: The Federal Weapons Commission was established to propertize the bullet-spectrum. They’re holding an auction to sell off the right to control certain bullet sizes. The winner gets to say how, where, and when bullets of that size may be used. (All other sizes, of course, are prohibited.) Oh, isn’t that funny — the gun control activists are buying up lots of the bullet sizes.
But hey! It’s property rights, not gun control, so it’s good. I’m sure glad those crazy Marxists didn’t convince us to adopt their “bullet commons” approach where you could sell guns that used whatever size bullet you wanted. It’s obvious that the auction system is much better for freedom.
For the record, I'm don't have terribly strong feelings either way about gun control. Washington has right-to-carry laws, and I may get a gun someday (for self-defense, and just to learn how to shoot). The point Schwartz is making is about the propertization of the electromagnetic broadcast spectrum, and the weird inconsistency of many libertarians on this subject (and many others involving various forms of "commons", including commons of intellectual property).
...and the programmer was enlightened
I often find Eric Raymond to be a rather annoying blowhard, but Master Foo Discourses on the Graphical User Interface is pretty good.
Thursday, January 22, 2004
Linux kernel developers can be real asses sometimes
Behold as Linux kernel developers express bizarro way-out-of-proportion bigoted responses to the perfectly reasonable suggestion that it might be worthwhile expending some effort getting kernel headers to be C++-friendly so that kernel modules can be written in C++.
Wednesday, January 21, 2004
Weep for the art of... porno movie posters?
Previously on this blog, I've linked to a site arguing that the art direction of magazine covers today is totally pedestrian and boring compared to what was regularly produced few decades ago. More recently, there was a a MeFi thread about a Slate article pointing out that the same was true of fashion photography (perhaps not surprising, given the close relationship between fashion photography and magazine covers).
All that's sad enough. But today, I came across memepool's link to a gallery of adult movie posters from the 60's and 70's, and this really bummed me out. A quick perusal leads to the shocking and depressing conclusion that even porno movie posters of the 60's and 70's were (on average) wittier, more daring, and more informed by the sophisticated visual language of the century's "high" art than ordinary movie posters of today.
Take, for example, the posters for Casting Call and The Marriage Manual. Now look at a typical movie poster of today, like The Last Samurai or Mona Lisa Smile. Even "artsy" films like 21 Grams and The Dreamers basically maintain the same formula: pedestrian layout designed solely to direct visual attention at big head shots of the stars, and a visual aesthetic that resolves around tarting up the design with phoned-in photoshop tricks and a portentous/beatific glow around the actors' images.
In fact, the only movie poster from the past year or two that I can recall straying from this formula is Mystic River, which, OK, does deserve some kudos for visually reflecting (ha, ha) the film's stark and dark aesthetic. Some of the Kill Bill posters weren't bad either.
But overall, it's a desert out there.
Most pithily brilliant and true blog post I've read in months
Ant's Not TeX
The Caml applications page led me to ANT, an alternative to TeX. Of course, none dare challenge the venerable TeX for industrial-strength typesetting of mathematical texts, but I can't count the times I've cursed at one totally crockish misfeature or another of TeX and LaTeX. Perhaps ANT might be worth looking into.
Monday, January 19, 2004
Another myth bites the dust.
Isn't it good to know that the British are spending their scientific research dollars on something worthwhile? (Figuring out whether I am being sarcastic or not is left as an exercise for the reader.)
