Friday, February 10, 2006

 

The Science of Hit Songs

This interesting article appeared at LiveScience.com

The Science of Hit Songs
By Bjorn Carey
LiveScience Staff Writer
posted: 09 February 2006
02:01 pm ET


When Ashlee Simpson tops the charts while a critically acclaimed ex-Beatle's album fails to crack the top 200, eyebrows go up in the marketing world.

So what makes a hit?

A new study reveals that we make our music purchases based partly on our perceived preferences of others.

Popularity contest

Researchers created an artificial "music market" of 14,341 participants drawn from a teen-interest Web site. Upon entering the study's Internet market, the participants were randomly, and unknowingly, assigned to either an "independent" group or a "social influence" group.

Participants could then browse through a collection of unknown songs by unknown bands.

In the independent condition, participants chose which songs to listen to based solely on the names of the bands and their songs. While listening to the song, they were asked to rate it from one star ("I hate it") to five stars ("I love it"). They were also given the option of downloading the song for keeps.

"This condition measured the quality of the songs and allowed us to see what outcome would result in the absence of social influence," said study co-author Matthew Salganik, a sociologist at Columbia University.

In the social influence group, participants were provided with the same song list, but could also see how many times each song had been downloaded.

Researchers found that popular songs were popular and unpopular songs were unpopular, regardless of their quality established by the other group. They also found that as a particular songs' popularity increased, participants selected it more often.

The upshot for markerters: social influence affects decision-making in a market.

This research is detailed in the Feb. 10 issue of the journal Science.

The Britney effect

The social-influence group was further divided into eight separate, non-interactive "worlds." Members of each world could not see the decisions of the other seven. The idea behind this was to observe multiple outcomes for the same songs and bands.

"If you look at Britney Spears, some people say she is really good. Others say she isn't good, she's just lucky," Salganik told LiveScience. "But by having just one argument, it's impossible to distinguish. However, if you have 10 worlds, and she's popular in all 10, then you can say she's actually good. But if she's only good in one, then you could say it was due to luck."

Although different songs were hits in each world, popularity was still the deciding factor, although the "best" songs never did very badly and the "worst" songs never did very well.

So what drives participants to choose low-quality songs over high-quality ones?

"People are faced with too many options, in this case 48 songs. Since you can't listen to all of them, a natural shortcut is to listen to what other people are listening to," Salganik said. "I think that's what happens in the real world where there's a tremendous overload of songs."

Alternatively, Salganik said, a desire for compatibility with others could drive the choice, since much of the pleasure from listening to music and reading books stems from discussing them with friends.

"If everybody is talking about 'Harry Potter,' you want to read it too," Salganik said.

Tuesday, February 07, 2006

 

Parasite Brain Surgeon

Science Tuesday.

Here is an incredibly interesting story about a parasite that has an interesting procedure for procreating. It seems like straight out of a science fiction story.

Found at Corante

The Wisdom of Parasites

Posted by Carl Zimmer

I collect tales of parasites the way some people collect Star Trek plates. And having filled an entire book with them, I thought I had pretty much collected the whole set. But until now I had somehow missed the gruesome glory that is a wasp named Ampulex compressa.

As an adult, Ampulex compressa seems like your normal wasp, buzzing about and mating. But things get weird when it's time for a female to lay an egg. She finds a cockroach to make her egg's host, and proceeds to deliver two precise stings. The first she delivers to the roach's mid-section, causing its front legs buckle. The brief paralysis caused by the first sting gives the wasp the luxury of time to deliver a more precise sting to the head.

The wasp slips her stinger through the roach's exoskeleton and directly into its brain. She apparently use ssensors along the sides of the stinger to guide it through the brain, a bit like a surgeon snaking his way to an appendix with a laparoscope. She continues to probe the roach's brain until she reaches one particular spot that appears to control the escape reflex. She injects a second venom that influences these neurons in such a way that the escape reflex disappears.

From the outside, the effect is surreal. The wasp does not paralyze the cockroach. In fact, the roach is able to lift up its front legs again and walk. But now it cannot move of its own accord. The wasp takes hold of one of the roach's antennae and leads it--in the words of Israeli scientists who study Ampulex--like a dog on a leash.

The zombie roach crawls where its master leads, which turns out to be the wasp's burrow. The roach creeps obediently into the burrow and sits there quietly, while the wasp plugs up the burrow with pebbles. Now the wasp turns to the roach once more and lays an egg on its underside. The roach does not resist. The egg hatches, and the larva chews a hole in the side of the roach. In it goes.

The larva grows inside the roach, devouring the organs of its host, for about eight days. It is then ready to weave itself a cocoon--which it makes within the roach as well. After four more weeks, the wasp grows to an adult. It breaks out of its cocoon, and out of the roach as well. Seeing a full-grown wasp crawl out of a roach suddenly makes those Alien movies look pretty derivative.

Ampulex%20emerging.jpg

I find this wasp fascinating for a lot of reasons. For one thing, it represents an evolutionary transition. Over and over again, free-living organisms have become parasites, adapting to hosts with exquisite precision. If you consider a full-blown parasite, it can be hard to conceive of how it could have evolved from anything else. Ampulex offers some clues, because it exists in between the free-living and parasitic worlds.

Amuplex is not technically a parasite, but something known as an exoparasitoid. In other words, a free-living adult lays an egg outside a host, and then the larva crawls into the host. One could easily imagine the ancestors of Ampulex as wasps that laid their eggs near dead insects--as some species do today. These corpse-feeding ancestors then evolved into wasps that attacked living hosts. Likewise, it's not hard to envision an Ampulex-like wasp evolving into full-blown parasitoids that inject their eggs directly into their hosts, as many species do today.

And then there's the sting. Ampulex does not want to kill cockroaches. It doesn't even want to paralyze them the way spiders and snakes do, since it is too small to drag a big paralyzed roach into its burrow. So instead it just delicately retools the roach's neural network to take away its motivation. Its venom does more than make roaches zombies. It also alters their metabolism, so that their intake of oxygen drops by a third. The Israeli researchers found that they could also drop oxygen consumption in cockroaches by injecting paralyzing drugs or by removing the neurons that the wasps disable with their sting. But they can manage only a crude imitation; the manipulated cockroaches quickly dehydrated and were dead within six days. The wasp venom somehow puts the roaches into suspended animation while keeping them in good health, even as a wasp larva is devouring it from the inside

Scientists don't yet understand how Ampulex manages either of these feats. Part of the reason for their ignorance is the fact that scientists have much left to learn about nervous systems and metabolism. But millions of years of natural selection has allowed Ampulex to reverse engineer its host. We would do well to follow its lead, and gain the wisdom of parasites.

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