MYTHBUSTERS 10/27: "Tablecloth Chaos"

[Christopher]

Tablecloth pull: As they said, the basic trick isn't a myth, just the scaled-up video. But it was interesting to see a breakdown of the science behind the trick. This is the sort of thing where the show is at its best -- presenting scientific concepts through a colorful demonstration/experiment, and presenting analytical thinking as the hosts try to figure out how to make it work.

It was interesting to learn what the parameters are for getting the trick to work. The bit about needing the cloth to start at the edge so that there's no "noise" (waves in the fabric) from being dragged over the edge was fascinating. It's also surprising that lighter stuff is more likely to survive the yanking because it creates less friction.

I'm not surprised the viral video was fake. If it wasn't a digital effect, my guess after watching half the episode was that the place settings were fake and made of lightweight plastic or foam or something. But Adam & Jamie lightened the place settings as much as possible and it still didn't work as shown.

I actually thought of the possibility that there'd been a clear layer between the tablecloth and the place settings, but I figured it'd be too heavy and get dragged off. It didn't occur to me that it could be bolted down at the far end. Like most magic tricks, it's so simple once you know the secret.


Ten percent of the brain: Of course this myth is total BS for many reasons, but it's nice to see the show debunk it at last. And given how scientifically sloppy the Junior Mythbusters have been in recent weeks, it's nice to see them doing a myth that pretty much requires them to be highly scientific because they need the help of actual scientists to make it happen.

Although their definitions were still kind of sloppy. They were approaching the myth in terms of how much of the brain is used at a time, with it taken as a given that every part of the brain is used at some point or another. But the way the myth was originally defined, the way it's widely interpreted, is that 90% of the brain is never used at all. And that's completely bogus for all sorts of reasons, and it would've been nice to see them point that out to a mass audience. Although I guess maybe that interpretation has been debunked enough by modern brain scanning techniques that it's been supplanted by the "10 percent at a time" interpretation which they were testing. So maybe it's not so unreasonable that they focused solely on that. And their tests did implicitly debunk the old version; I just wish they'd pointed that out specifically, that even if Tory only "maxed out" at 30% at a time, all of the brain's volume is used at one time or another.

I've never heard of an MEG (magnetoencephalogram) before. Interesting gizmo.

[Mr. Adventure]

The tablecloth was fun and not completely obvious. I don't know that the 10% thing refers to actual brain matter never being used, and really the percentage was off but not the notion that we don't use full capacity.

But forget all that, the next myth they need to test is that Kari is getting progressively hotter every week.

[Trekker4747]

I've always understood the "10% of the brain" thing to be we only use 10% of its capability and not 10% of it period.

More "using a super computer to play solitare" and less "90% of your brain is just pure mush."

The idea being that the connections and such of the brain are so vastly complex and staggering that it's possibly capable of doing a lot more than what we do with it. Not that only 10% of it's physical mass is used. Glad to hear this episode was a bit better, I need to check out the DVR tomorrow.

The first few in this batch of episodes hasn't been so great.

[Christopher]

Mr. Adventure wrote:

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I don't know that the 10% thing refers to actual brain matter never being used, and really the percentage was off but not the notion that we don't use full capacity.

Screecher4747 wrote:

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I've always understood the "10% of the brain" thing to be we only use 10% of its capability and not 10% of it period.

As I said, that's the way it tends to be interpreted in modern times because the original interpretation has been discredited by modern brain studies showing activity throughout the brain. But for a long time, the myth was that literally nothing whatsoever was done with 90 percent of the brain's volume.

I've heard two stories for how this originated. One is that an early experiment that was only testing for sensory and motor nerve activity detected in in 10% of the brain's volume and reported the other 90% as "quiet," and the media misunderstood that to refer to any brain activity rather than just the specific types they were testing for. The other is that they found that heavily lobotomized or brain-damaged patients could still function with as little as 10% of the brain intact, and the idea that we could get by with only 10% got morphed into the assumption that we did only use 10% at all.

Either way, the folk statistic got picked up and propagated by charlatans and true believers (and fiction writers), becoming the basis for countless claims that we could achieve psychic superpowers if we could harness the "untapped" 90% of our brains. And that's the truly mythical part here, another thing I wish the team had addressed. Even under the modern interpretation, that it's a matter of activity or capacity rather than volume, it still doesn't make sense. If most of the brain's neurons were firing at once, I believe that would be called an epileptic seizure or something similar.

Whether you go with the mass/volume percentage or the percentage of activity/capacity, it's still BS for the same reason. Why would evolution give us ten times as much capacity as we actually need? Evolution doesn't work that way. If you don't need something, it tends to atrophy or vanish as an unnecessary waste of resources. Our brains would've evolved to give us as much capacity as we needed to lead our lives. True, evolution often opens up new potentials beyond basic needs, which is how species develop new traits to begin with; somewhere in our past, brain evolution took a turn that increased its potential beyond survival needs, and developing that potential led us to become human. But that's just it. Once evolution produces such a potential, a species tends to use it. If our brains had the capacity to operate at ten times our current level, then they would operate at up to ten times our current level.

Unless, of course, there were some evolutionary drawback to using that much brainpower. In which case that branch of the species with that much potential would die out, and those with more limited brains would survive.

In any case, Tory's brain scans showed that there's no single percentage figure to how much of the brain gets used. It depends on the task. Different parts of the brain get called on at different times. Same with the body -- you just use part of it for eating, part of it for typing, a lot of it for walking, most of it for swimming, etc. A brain that operated at 10% of capacity all the time would be pretty rigid and useless.

But forget all that, the next myth they need to test is that Kari is getting progressively hotter every week.

I think we can just call that confirmed right up front.

[Roger Wilco]

I heard once that the 10% myth is a Scientology invention, but I don't know if that's true. Anyways, it's clearly nonsense. Evolutionary the brain doesn't make any sense if it's not used considering how much ressources it costs our bodies to keep it running.

[Christopher]

Scientologists are among the many frauds who use the ten percent myth to try to convince people that they can harness untapped powers of the mind if they pay enough money to people who will teach them how. But they didn't invent it. The myth was already around in the early 20th century, certainly no later than the 1930s. Scientology was founded in 1952.

Some links on the myth:

http://en.wikipedia.org/wiki/10%25_of_brain_myth

http://www.snopes.com/science/stats/10percent.asp

http://www.scientificamerican.com/ar...rcent-of-brain

[Trekker4747]

Some quick thoughts.

In the past I've seen shows talk about the table cloth pull and one thing I was recalling was that one thing to do was to start pulling the table cloth slowly and then yank it. I also seem to recall it being said to pull the cloth low and with a snap.

Using the bike, which granted was part of the myth they were busting, doesn't do any of this. It's just dragging the cloth out at a quick, constant, speed. Not quite the same thing as a quick snap. Setting up a camera and grid pattern may also have helped to see the speed Adam was yanking the cloth at. But, the angle of yanking may not be right, etc. Something to think about in any potential revisit. (Which may or may not involve rockets because, face it, we've not had any fire or explosions yet.) All interesting none the less and I'm sure the video was faked too.

Also something to consider: Adam determined that the cloth's edge had to be as close to the edge of the table as possible to not cause too much turbulence in it as it's yanked out. It's possible this is why the longer version didn't work. As the longer cloth got drug further and further across the length of the table more turbulance was caused in it and then all hell broke out.

The 10% of the brain stuff was interesting because, as I noted above, I figured that, mostly, it was a myth or just an "idea" that the brain is capable of a lot more and we've not yet seen our full potential. Not that we're literally only using 10% of it. Nice to see the Junior Mythbusters doing a highly scientific myth like this. Let's hope this episode sets a better baseline for the new crop of episodes than the past couple of ones have.

[Christopher]

Screecher4747 wrote:

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Using the bike, which granted was part of the myth they were busting, doesn't do any of this. It's just dragging the cloth out at a quick, constant, speed. Not quite the same thing as a quick snap.

Well, no. In the version that duplicated the viral video, the bike started from rest and thus was accelerating while it pulled the cloth away, not moving at constant speed. In the subsequent tests, they added enough rope that the bike could accelerate to a high, steady speed before the rope became taut, at which point the cloth would've almost instantly accelerated from zero to 50 or 100 MPH depending on the test. I'd certainly call that a quick snap, or as close as a tablecloth that long could possibly get to one.

The 10% of the brain stuff was interesting because, as I noted above, I figured that, mostly, it was a myth or just an "idea" that the brain is capable of a lot more and we've not yet seen our full potential. Not that we're literally only using 10% of it.

See the links I provided. The myth has taken many forms over the decades, precisely because it's just something people have heard and made assumptions about rather than actually researching. Any folk belief that gets propagated through pop culture that way is going to mutate into many different versions.

[Mr. Adventure]

Christopher wrote:

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Scientologists are among the many frauds who use the ten percent myth to try to convince people that they can harness untapped powers of the mind if they pay enough money to people who will teach them how. But they didn't invent it. The myth was already around in the early 20th century, certainly no later than the 1930s. Scientology was founded in 1952.

Some links on the myth:

http://en.wikipedia.org/wiki/10%25_of_brain_myth

http://www.snopes.com/science/stats/10percent.asp

http://www.scientificamerican.com/ar...rcent-of-brain

Those links seem to suggest to me that the 10% being actual brain tissue and 10% capability have both been around for a while.

[Christopher]

I'm sure they have, because as I said, it's taken many different forms over the decades. But the "capability" version seems to have become the dominant one these days, at least in my experience.

[WeAreTheBorg]

Dunno how they went 7 seasons without busting the 10% brain myth.

[Brent]

It does show one thing though, we don't use the full potential of our brains. I do wonder what would happen if we did.

[Alidar Jarok]

We'd be slightly smarter?

[Mr. Adventure]

Brent's Brains wrote:

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It does show one thing though, we don't use the full potential of our brains. I do wonder what would happen if we did.

I like the hope that there's a little more out there. I think it'd be a bit sad to know there's nothing more to give.

[Christopher]

Brent's Brains wrote:

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It does show one thing though, we don't use the full potential of our brains. I do wonder what would happen if we did.

It doesn't show any such thing. It only shows that the specific thing the machines were designed to detect was happening in only certain parts of the brain at any given time. And the brain's not a simple, monolithic system. It has a lot of things going on, a lot of different systems and subsystems that play different roles. Parts that aren't engaged in whatever active process is going on at a given moment may still play a support role. By analogy, the frame and suspension of a car don't actively deliver power to the wheels, but that doesn't mean they aren't being used when the car is in motion.

Consider how much of the brain is memory storage. There's never going to be an instance where a person needs to call on every memory in the brain at the same time, so there's never going to be a need for all the memory pathways to be stimulated at once. So even at "full potential," there isn't going to be activity in 100 percent of the brain at once. Indeed, if the whole brain were active at the same time, it would just be white noise, not coherent thought. Thought is a pattern of neural activity, and there can be no pattern in total uniformity. Does a page of a book fall short of its true potential if it isn't 100% covered in ink? No. It needs the space between the letters in order for the text to exist. Its fullest potential is achieved at a lower level of coverage, and adding more coverage beyond that optimal balance just decreases its potential.

There are plenty of people who use their brains to their fullest potential -- geniuses, prodigies, and people who apply themselves really, really hard. But it's not based on what percentage of your neurons are firing or anything as simplistic as that. It's based on how well you use what you've got.