Sunday, September 30, 2012

30 Second Science: Pareidolia

Pareidolia (Pair-eye-dough-lee-ya) is the phenomenon that causes the human brain to perceive random stimulation as significant. It's the reason why this house looks like it's screaming at you.


and the reason behind seeing this face on the surface of Mars.1


and the reason why just about any circle with "eyes" and a "mouth" will look like a face, even if it is completely lacking in any real human features.

In fact, let's see how distorted that face can get before you no longer see it as a face.

still a face?
Maybe it looks a little alien, but still a face to me.

Even when I separated the eyes between the mouth it still looks like a face. I see it as two eyes and a long nose if I tilt my head to the right.2 

Pareidolia is also what causes something random, like ink in the Rorschach tests, to look like something else.
Oh, sorry. Wrong Rorschach.

Your brain will attempt  to interpret the random ink blots in the image above. Supposedly how you interpret the image gives insight into your psychological state, though there are good reasons not to believe that is the case.

The reason you see a face so easily in all of these examples is that you're brain has evolved (there's that pesky "E" word I keep bringing up) to quickly recognize faces. Carl Sagan hypothesized that the ability to recognize faces would be an important survival advantage for early humans. Being able to quickly identify a friend or foe could be the difference between life and death. This idea is related to the idea of a pattern-seeking mind that I have already talked about. The human brain is great at picking out patterns in random noise. Sometimes too good at it.

Related to pareidolia is the phenomenon known as sine wave speech. Matt Davis is a researcher at the MRC Cognition and Brain Sciences Unit. The following clips are from his website. Listen to this audio a few times. It should sound like (to quote my five year old) "a bunch of silly whistles". It may slightly resemble speech, and you may make out a few words, but for the most part it's nonsense (my five year old says he heard it say "I love you"). Now listen to this audio clip, and the original audio clip once more. Suddenly, with this new context, the first audio doesn't just sound like whistles and noise. Instead you can hear, almost clearly, a voice in the whistles. My five year old was able to quickly tell me what the voice was saying when he heard the whistles again. The shocked look on his face was priceless. He knew that his brain had just played a trick on him. I doubt you will hear it as only whistles ever again. Of course, this isn't quite the same as pareidolia. You don't need any perceptual insight to see a face on Mars or in a house. You just need millions of years of evolution to force your brain to see it that way.


Notes
[1] Just to be clear, that is not a sculpture from an ancient human-like civilization on Mars. It is a hill with rocks randomly strewn across it. Your brain interprets this randomness as a face. Higher resolution images have put this controversy to bed long ago - unless you're a conspiracy theorists, then it was all a big government cover up. Also, look behind you. They're watching you.
[2] After I had made this image, the first thing I did was tilt my head to the right. When I showed this to my brother he immediately tilted his head to the right. I wonder how many of you did the same thing. Your brain knew just where the face was, didn't it? 

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Thursday, September 27, 2012

30 Second Science: The Life and Death of a Star

One of my favorite science blogs is written by Phil Plait at Bad Astronomy.

Yesterday he posted this 14 minute video about the life and death cycle of a star. It's a pretty interesting video, and I highly recommend the 14 minutes.



After watching this video I was left with one question: How are elements larger than iron formed? As you saw, fusion creates all the elements up to iron just fine. At this point fusion switches from being exothermic (releasing energy) to endothermic (requiring energy). It turns out that neutron capture creates the other elements. A neutron has no charge and can therefore penetrate the electron cloud and collide with the nucleus, creating a more massive element. After an electron is emitted (beta decay), a new element is formed.1

A big thanks to Phil Plait at Bad Astronomy for posting the video and a big thanks to the original creator, Tony Silva.

Notes
[1] I have a few friends studying nuclear chemistry. I'm very nervous about my whole explanation of how larger elements are formed. Let's see if they correct me anywhere...

Scientist in the Spolight: Linus Pauling

Today I'm putting the spotlight on scientist, educator, activist, author, and peacemaker Linus Pauling.


Pauling was an amazing American scientist. To date he is the only person to be awarded two unshared nobel prizes in different fields.1 In 1954 he won the Nobel prize in Chemistry for his work on the chemical bond. He helped develop the chemistry theories of resonance, ionic bonding, and hybridization.

His understanding of the atom made him an obvious scientist to invite to work on the Manhattan Project, the joint venture between the United States, Canada, and the United Kingdom to develop the atom bomb. He chose not to participate. Instead he chose to work on development of rocket propellants, synthetic quartz, and artificial blood serum. He was an peace activist during and following World War II. This peace activism led to him receiving the Nobel Peace Prize in 1962.2

Unfortunately Pauling's story doesn't end here. No honest biography of Linus Pauling can exclude his ventures into pseudoscience. Although he is responsible for many advances in chemistry, he is also responsible for the widespread belief that large amounts of Vitamin C can prevent the common cold.  Pauling proposed that doses of 1,000 mg of vitamin C daily will reduce the incidence of colds by 45% for most people but that some people need much larger amounts.3 When controlled studies of Vitamin C treatments were shown to be ineffective, Pauling doubled down, claiming that 75% of cancers can be prevented and cured by Vitamin C alone. In fact, Vitamin C increases the rate of cancer growth at doses of 1 to 5 grams per day, and only suppresses the cancer growth rate at doses on the order of 100 grams per day (which is close to the lethal dose).

So is Linus Pauling wrong for having a bad idea? No, but when presented with evidence to the contrary he refused to accept the evidence. Pauling won two Nobel prizes, and this is one proof that proponents of Vitamin therapy give to validate the treatment. This is the logical fallacy known as "Argument from Authority". An expert opinion cannot be used to prove the validity of an argument. Pauling's opinion, even as a Nobel prize winning chemist, does not influence the veracity of his arguments on Vitamin C. They must stand on their own (which they haven't). Similarly, Pauling's opinion on his Nobel prize winning work doesn't influence the veracity of his work. It too must stand on its own (which it has).



Notes

[1] Marie Cuire won two nobel prizes (Chemistry and Physics), but her husband shared the prize for Physics with her husband, Pierre.
[2] An interesting fact. Pauling's activism brought with it suspicion of being a communist supporter and he was denied a passport in 1952. Luckily he was able to clear things up by 1954 and was able to accept his 1954 Nobel Prize in Chemistry. In 1962 he was awarded a Nobel prize for the same reason that nearly kept him from accepting his first Nobel prize. 
[3]  From his book "Vitamin C and the Common Cold" written in 1976.

Monday, September 24, 2012

30 Second Science: A Dinosaur Duel

In today's "30 Second Science" I'm going to answer an age old question: Who would when in a fight, Tyrannosaurus or Stegosaurus.

Movies like Jurassic Park are compelling evidence that scientists can take DNA that has miraculously survived decomposition over 150 million years, splice it together with frog DNA, and create a living dinosaur. It's legitimate science, believe me.1 

Pictured: A scenario that's just as likely as Jurassic Park

Bad science aside, movies like Jurassic Park excite our imagination. So I want to pose the question: Who would win in a fight between the amazing Tyrannosaurus and Stegosaurus?

Now, although I hope the comment section of this post devolves into a geek filled internet flame war to actually answer the question, I have a scientific point to make from this question. 

Stegosaurus lived roughly 150 million years ago in the Jurassic period. On the other hand, Tyrannosaurus lived only 67 million years ago in the Cretaceous period. This leaves a few observations to be made:

1. The movie Jurassic Park is a horrible name. Cretaceous Park would be more fitting, since it was during this time frame that both Tyrannosaurus and Velociraptor lived.
2. Stegosaurus would never have fought Tyrannosaurus. They lived nearly 83 million years apart from eachother.
3. We are separated from Tyrannosaurus by less time than Tyrannosaurus is separated from Stegosaurus.

That final one is mind blowing to me, and it shows just how bad at understanding long periods of time the human brain can be. When I hear 150 million years ago and 67 million years ago, my brain just understands both of those as "a really, really long time ago". This inability to understand large numbers is a common pitfall when trying to understand science (and I'll write more on that later).

And now, the point of this entire post. Funny cartoons about Tyrannosaurus Rex. Also, this great clip from firefly.











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Notes
[1] Or you could be smart, not believe me when I say that, and anticipate a "Bad Science in the Movies: Jurassic Park". It's up to you.