Speaking of Poo... Poo as a Key for Evolution

The Cambrian period began a little over 500 million years ago. Before the Cambrian period, life on earth consisted of mostly single-celled organisms and bacteria. Afterwards the evolutionary ancestors of all the major groups of living things today were hanging around the planet. So what caused this evolutionary leap? According to one scientist, poop.

Biogeochemist Graham Logan published his opinion on the matter a few years ago. He points out that feces producing creatures, ones that ate food then excreted it like humans today, first arrived around 40 million years before the Cambrian period. He argued that their poo was what allowed oxygen levels to rise, and evolution to explode.

Before the advent of feces producing organisms, bacteria kept oxygen levels low. Plankton produced oxygen, but slowly. When they died, bacteria ate them and used most of the oxygen they produced to digest the dead plankton. This meant less oxygen for everyone else, and when you don’t have a lot of oxygen you’re apparently not going to be using all your energy on evolving into higher life forms.

Here’s where the feces creatures come in. Instead of bacteria eating the plankton bodies, these creatures, with their guts and what have you, would eat the plankton themselves. Then they’d excrete them. The excretions dropped to the ocean floor quickly and the bacteria starved. This meant lower bacteria populations, meaning they used less oxygen so everyone else had more.

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Why Terrorrism Does Not Work

...like all cognitive biases, correspondent inference theory fails sometimes. And one place it fails pretty spectacularly is in our response to terrorism. Because terrorism often results in the horrific deaths of innocents, we mistakenly infer that the horrific deaths of innocents is the primary motivation of the terrorist, and not the means to a different end.

I found this interesting analysis in a paper by Max Abrams in International Security. "Why Terrorism Does Not Work" (.PDF) analyzes the political motivations of 28 terrorist groups: the complete list of "foreign terrorist organizations" designated by the U.S. Department of State since 2001. He lists 42 policy objectives of those groups, and found that they only achieved them 7 percent of the time.

According to the data, terrorism is more likely to work if 1) the terrorists attack military targets more often than civilian ones, and 2) if they have minimalist goals like evicting a foreign power from their country or winning control of a piece of territory, rather than maximalist objectives like establishing a new political system in the country or annihilating another nation. But even so, terrorism is a pretty ineffective means of influencing policy.

In other words, terrorism doesn't work, because it makes people less likely to acquiesce to the terrorists' demands, no matter how limited they might be. The reaction to terrorism has an effect completely opposite to what the terrorists want; people simply don't believe those limited demands are the actual demands.

This theory explains, with a clarity I have never seen before, why so many people make the bizarre claim that al Qaeda terrorism -- or Islamic terrorism in general -- is "different": that while other terrorist groups might have policy objectives, al Qaeda's primary motivation is to kill us all. This is something we have heard from President Bush again and again -- Abrams has a page of examples in the paper -- and is a rhetorical staple in the debate. (You can see a lot of it in the comments to this previous essay.)
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Although Bin Laden has complained that Americans have completely misunderstood the reason behind the 9/11 attacks, correspondent inference theory postulates that he's not going to convince people. Terrorism, and 9/11 in particular, has such a high correspondence that people use the effects of the attacks to infer the terrorists' motives. In other words, since Bin Laden caused the death of a couple of thousand people in the 9/11 attacks, people assume that must have been his actual goal, and he's just giving lip service to what he claims are his goals. Even Bin Laden's actual objectives are ignored as people focus on the deaths, the destruction and the economic impact.

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Why We're So Good at Recognizing Music

Amazingly interesting research, well worth the full read.

'Listen to this," Daniel Levitin said. "What is it?" He hit a button on his computer keyboard and out came a half-second clip of music. It was just two notes blasted on a raspy electric guitar, but I could immediately identify it: the opening lick to the Rolling Stones' "Brown Sugar."

Then he played another, even shorter snippet: a single chord struck once on piano. Again I could instantly figure out what it was: the first note in Elton John's "Benny and the Jets."

Levitin beamed. "You hear only one note, and you already know who it is," he said. "So what I want to know is: how we do this? Why are we so good at recognizing music?"
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"By the age of 5 we are all musical experts, so this stuff is clearly wired really deeply into us,"

Last summer he published "This Is Your Brain on Music," a layperson's guide to the emerging neuroscience of music. Levitin is an unusually deft interpreter, full of striking scientific trivia. For example we learn that babies begin life with synesthesia, the trippy confusion that makes people experience sounds as smells or tastes as colors. Or that the cerebellum, a part of the brain that helps govern movement, is also wired to the ears and produces some of our emotional responses to music. His experiments have even suggested that watching a musician perform affects brain chemistry differently from listening to a recording.
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Ultimately, scientists say, his work offers a new way to unlock the mysteries of the brain: how memory works, how people with autism think, why our ancestors first picked up instruments and began to play.
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"When we saw all this activity going on precisely in sync, in this order, we knew we had the smoking gun," he said. "We've always known that music is good for improving your mood. But this showed precisely how it happens."
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The subtlest reason that pop music is so flavorful to our brains is that it relies so strongly on timbre. Timbre is a peculiar blend of tones in any sound; it is why a tuba sounds so different from a flute even when they are playing the same melody in the same key. Popular performers or groups, Levitin argued, are pleasing not because of any particular virtuosity, but because they create an overall timbre that remains consistent from song to song. That quality explains why, for example, I could identify even a single note of Elton John's "Benny and the Jets."

"Nobody else's piano sounds quite like that," he said, referring to John. "Pop musicians compose with timbre. Pitch and harmony are becoming less important."

Levitin's work has occasionally undermined some cherished beliefs about music. For example recent years have seen an explosion of "Baby Mozart" videos and toys, based on the idea, popular since the '80s, that musical and mathematical ability are inherently linked.

But Levitin argued that this could not be true, based on his study of people with Williams syndrome, a genetic disorder that leaves people with low intelligence. Their peak mental capacities are typically those of a young child, with no ability to calculate quantities. Levitin once asked a woman with Williams to hold up her hand for five seconds; she left it in the air for a minute and a half. "No concept of time at all," he said, "and definitely no math."

Yet people with Williams possess unusually high levels of musical ability. One Williams boy Levitin met was so poorly coordinated he could not open the case to his clarinet. But once he was holding the instrument, his coordination problems vanished, music, science, and he could play fluidly.

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