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Oct 312005
 

In one experiment with captive chimpanzees, the chimps wouldn’t help a buddy to get food, even though it cost themselves nothing. The chimpanzees were given a choice of two ropes to pull for food; one yielded food for the chimp, and the other resulted in food for both the chimp himself and a nearby chimp in another cage. The animals weren’t any more likely to pull one rope than the other. I don’t know enough about chimp behavior to know what this might have to say about how they act in the wild, but as this news story points out, we need to be careful about interpreting these results. The researchers are looking for other ways to run the experiment, maybe working with chimps who are related to each other, or giving them a chance to trade places so that each chimp gets a chance to see both sides.

http://www.nature.com/news/2005/051024/full/051024-7.html*

On the other hand, I was struck by something I ran across in Frans de Waal’s new book, Our Inner Ape. He wrote that rats will stop pressing a bar for food if the lever also delivers a shock to another rat, and that monkeys are even more strongly inhibited from getting food for themselves at another’s expense (he didn’t say what kind of monkeys).

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Dreaming of danger

 Psychology  Comments Off
Oct 302005
 

I’ve heard a number of theories for why we dream. It seems to be related to consolidating memories, including memories of physical skills we’re learning. Perhaps it also helps the brain process the stimuli it has received during the day, including emotions that we don’t really know what to do with. Maybe what’s going on in our brains when we’re dreaming is like what goes on when we’re awake, except that the conscious mind is not there to organize 0ur mental activity. I don’t think anyone really knows. One theory is that in some dreams, we rehearse what to do if we’re faced with a physical threat. Here’s a news story about a sleep disorder in which people act out their dreams in sometimes violent ways (trying to set the bed on fire, kicking a hole in the wall). Usually when you’re asleep you’re body is immobilized, so you don’t actually do the things you’re dreaming of doing; in this disorder, the mechanism for immobilization fails somehow. A new study shows that people with this disorder also have more violent dreams than most people do. If this is sort of an exaggerated version of a natural phenomenon, it may tell us something about why we dream.

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Oct 292005
 

I’ve seen a somewhat hard-to-follow news story coming out of the Clovis in the Southeast conference this weekend. The Clovis culture thrived in North America roughly 10,000-15,000 years ago. The story talks about a supernova wiping out these people, but then it talks about comets rather than a supernova with no obvious connection between the two. You can find a much better account in this story from last month, which came out of a different conference. What appears to have happened is that scientists found pits in the tusks of mastodons, made by projectiles moving so fast that the only natural explanation is that they were tiny particles of supernova debris. This first wave of debris arrived 7,000 years after the supernova, and then 21,000 years after that, a “comet-like formation”, also originating from the supernova, arrived to spread destruction over North America and do in the Clovis people. I guess I’m not up on what you can expect from a supernova at close quarters (250 light years in this case), so I can’t really judge how much sense this makes. If it’s true, it gives an insight into how this planet is not entirely benign toward living things.

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 Posted by at 8:10 pm
Oct 282005
 

Forbes.com has a special section about communication, with a number of interesting articles, including an article about communicating with extraterrestrials. I like the suggestion of sending the contents of the Google servers, which Seth Shostak of the SETI Institute made, although it seems like a lot to digest. It seems like there’s got to be some way to distill the information about Earth down to something more manageable, but it’s hard to imagine such a distillation that would please everyone. For some reason it’s a little sad, or maybe just touching, to think about how eager people are to communicate with aliens when we don’t even communicate all that well with each other. (But maybe this is because I just got back from seeing Proof, which struck me as enough to leave anyone a bit melancholy.)

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 Posted by at 11:31 pm  Tagged with:
Oct 272005
 

What is the goal of conservation biology or environmental activism? (Or to put it more generally, what is our obligation toward nature?) If the goal is to preserve nature in as pristine a state as possible, untouched by humans, how does this account for the fact that humans are not separate from nature but rather a part of it? This afternoon I heard a lecture by J. Baird Callicott, a noted environmenta philosopher, about this question. (The talk was organized by Indiana University’s Poynter Center for the Study of Ethics and American Institutions.)

Callicott outlined some of the attitudes toward humans and nature over time; most relied on some kind of metaphysical essential attribute of man that separated him from nature. Man was created in the image of God, for example, or man was the rational animal. Darwin turned this kind of thing upside down when he said that our supposedly unique capabilities (e.g., for speech or intelligence or ethics) evolved over time from proto-capabilities in other species. This idea that there is no boundary between us and other species is central to Aldo Leopold’s land ethic, which “changes the role of Homo sapiens from conqueror of the land-community to plain member and citizen of it.” (Quote from A Sand County Alamanc)

But, as Callicott stated the resulting paradox: “If Homo sapiens is a part of nature, then human actions, no less than the actions of other species, are natural–just another intriguing chapter in the biography of the earth, no more subject to ethical praise or condemnation than the actions of other species.” And of course many of us would take vigorous exception to that idea, which has consequences for how we treat the land and the creatures we share it with. (In his book Conversations with the Archdruid, John McPhee quotes Floyd Dominy (former Commissioner of Reclamation, and big on dams) as saying: “Nature changes the environment every day of our lives–why shouldn’t we change it? We’re part of nature.”)

Callicott found a resolution to the paradox by considering the various time scales operating in nature, from the organismic (operating at the level of the individual organism, and including processes of metabolism and photosynthesis), to the ecological (processes of succession and disturbance), climatic, evolutionary, and geomorphological. The processes of the organismic scale range in duration from one day to about a thousand years, of the ecological scale from one year to thousands of years, and so on, with each scale having a longer timespan. Geomorphological cycles are the longest of all, some of them stretching into the billions of years.

Humans speciated on the evolutionary time scale, and evolved the capacity for culture on the same scale, which places humans and human culture both within the time scales of nature. But human culture, once launched, is Lamarckian (relying on the inheritance or transmission of acquired or learned characteristics) rather than Darwinian, and thus operates on a much shorter time scale (and Callicott presented a brief summary of weapon technology to illustrate that it’s not only faster, it’s speeding up these days).

And this is where the resolution of the paradox arrives: we cross the boundary between human and nature when we begin to “transform ecosystems faster than other biota can adapt.” So we are a part of nature, not set apart by God or by our special abilities or by something in our essence like our rationality; but at the same time we are not free to do whatever we want and claim that all our actions are natural and thus value-neutral and not subject to moral judgment. We need to act appropriately with respect to the spatio-temporal scales of nature.

Well, there it is in a nutshell; the talk lasted an hour, with half an hour of question-and-answer afterward, so this is just a sketch, but it should give you the gist of it. I found it a reasonably coherent way to resolve something that I have puzzled over. I need to think about it some more, but this certainly gave me some ideas to chew over (and some more ideas for books to read). Some interesting questions came up afterward, including one about practical recommendations arising from all this. He gave several examples of ways to make our footprint smaller, e.g., vegetarianism (not for the sake of livestock, who might not be alive at all if we weren’t raising them for food, but for efficiency of land use–since we get relatively little food out of animals for each pound of grain we put in, it would be more efficient to eat lower on the food chain–which frees land up to go back to an uncultivated state). He mentioned an initiative he’s involved in in Denton, Texas, where he lives, to concentrate development so as to leave room for green space. (If it can happen in Texas, he said, it can happen anywere.)

I’d be very interested in hearing anyone else’s thoughts on this subject. Like I said, I’m still chewing it over myself.

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 Posted by at 8:35 pm
Oct 262005
 

When asked to adjust the color of a light until it was pure yellow, participants in a study all chose pretty much the same wavelength of light. So evidently one person’s pure yellow was nearly the same as another’s. However, researchers were able to use adaptive optics (a technique used in astronomy, and adapted for use in the eye) to get a look at the retinas of these people in unprecedented detail, and they found that the distribution of cones varies significantly (by as much as a factor of 40). This is surprising, given how uniform the perception of color seemed to be. This indicates that a lot of our color processing goes on in the brain, where something is compensating for the differences in optical hardware (the retina) to produce a calibrated perception of color.

http://www.rochester.edu/news/show.php?id=2299

This got me to thinking about the nature of our relationship to reality, mediated as it is by our senses that are still in some ways pretty mysterious. Coincidentally, my friend Greg recently introduced me to some of the visual wizardry of the Computational Visual Cognition Lab at MIT. For some interesting takes on visual perception, check out this lab’s gallery (http://cvcl.mit.edu/gallery.htm). The angry/calm face and Thatcher/Blair illusions are pretty weird.

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Oct 252005
 

Here’s a cool story about monkeys, showing how something that in humans would be called a personality trait varies with habitat and food source. Researchers from Harvard studied two species of monkeys, cotton-top tamarins and common marmosets, and found that their tendency to be impulsive or patient is related to the way they gather food. The monkeys were faced with choices: how long to wait for a bigger food reward before settling for a smaller but more immediate reward, and how far they were willing to travel to get to more food, instead of settling for a smaller amount nearby. (Humans face similar choices and adopt different strategies depending on the circumstances, which is why we have contradictory proverbs like “A bird in the hand is worth two in the bush” and “Nothing ventured, nothing gained”.) The marmosets eat tree sap, which means they need to wait for the sap to come out of the tree, and they were more willing to wait for a bigger reward than the tamarins, who need to catch bugs (and hence must act quickly to get their food, or it will get away). When it came to the spatial test of patience, though, the marmosets were less willing to travel (less patient in overcoming spatial obstacles) than the tamarins; the marmosets have a smaller range over which they travel for food.

http://www.sciencedaily.com/releases/2005/10/051025080057.htm

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Oct 242005
 

This press release from Carnegie-Mellon describes some very cool work on how facial expressions relate to how stressed we are. When people were put through a stressful experience, those who reacted with an angry or indignant facial expression had lower readings for various stress indicators (cortisol, heart rate, blood pressure) than those who looked frightened. I knew that Darwin had written a book about facial expressions and emotions, but I didn’t know until I read this that he had speculated about a link between expressions and biological responses to events. This study follows up on his ideas. One of the more intriguing points is that our reactions to negative emotions can differ, and there isn’t a single type of reaction common to both anger and fear. And in some circumstances, anger can be considered a more useful response. As someone who is far more prone to fear than anger, I find all this very interesting.

http://www.cmu.edu/PR/releases05/051024_faces.html

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