* The Breaking Ball Illusion * The Man Who Mistook Every Face * Wet Dogs Rule * Feeling Faster, not Better * Moths Mimic Bats * Untangling the Heliosphere *

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copyright jpstanley, cc-by-nc-sa-2.0
Well, it's Halloween this weekend, and your kids will soon be coming home with a bag full of assorted goodies - kind of like today's program.

We've got a couple of surprise treats in our bag of stories, such as the fact that baseball's famous breaking ball is just an illusion; and that there's a precise formula for how a dog shakes the water off its fur.

We also have some truly rare treats, including an extraordinary story about a man who cannot recognize any faces - but compensates with his other senses. And a similar story about blind people who can react to touch much faster than most.

And finally, we'll give you some truly tasty treats about the solar system's heliosphere, and a toxic moth that can imitate a bat.

But first - Steeee-rike!

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The Breaking Ball Illusion
curveball.jpg
curveball grip, copyright VideoJug, cc-by-nc-sa-2.5

As The San Francisco Giants take on the Texas Rangers in this week's World Series, much is made of the pitching match-ups.  Some pitchers are known for specific throws, but all must have a good breaking ball, which can be either a curveball or fastball that suddenly drops, rises or changes direction as it nears the batter.  Dr. Arthur Shapiro, a psychologist who specializes in visual perception and cognitive neuroscience at American University in Washington, DC, has analyzed the curveball and found that while it really does curve, the break is an illusion.  As the ball nears the plate, it moves from central vision to peripheral vision, resulting in a 'gap' in the path of the ball as seen by the batter.  The brain cannot process the two areas of vision at once, and the resulting 'gap' creates the illusion that the ball has changed course. .
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The Man Who Mistook Every Face
face_recognition.jpg Images like these are used to test patients with prosopagnosia credit:  Lily Solomon-Harris, York University

Prosopagnosia is a rare neurological disorder, in which the ability to identify faces is lost or severely impaired.  Those who suffer from the disorder can lead completely normal lives, but are not able to recognize faces, including facial expressions, facial emotions, or distinguish male from female facial features.  But the patient studied by Dr. Jennifer Steeves, an Associate Professor of Psychology at York University in Toronto, also has an inability to recognize objects. So she set up a series of experiments using visual and voice cues for both faces and specific objects - in this study it was cars.  The patient was able to expertly use the audio cue to identify people, but was no better than a control group in identifying cars and car horns.  This suggests that the brain has its own neurological pathway for facial recognition.  

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Wet Dogs Rule

When  your dog climbs out of the lake and shakes itself dry, drenching everything in sight, it's actually accomplishing a remarkable feat.  It's rotating around its central axis at a frequency of better than four hertz, and in the process, ridding itself of a substantial amount of water.  Dr. David Hu, a mechanical engineer at the Georgia Institute of Technology, and his students, have been studying how furry animals dry themselves, because this is a far more efficient way of drying than we use in things like washing machines.  Using high speed film to study animals as diverse as mice and tigers, Dr. Hu has found that they all obey a formula that ensures that they shake at precisely the right frequency to dry themselves, no matter what their size - a formula he's calling the "wet dog rule.".

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Feeling Faster, not Better
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Reading braille - copyright antonioxalonso, cc-by-2.0

Do blind people really compensate for their lack of vision by developing other more acute senses, like touch?  This conventional wisdom has now been tested by Dr. Daniel Goldreich of the Department of Psychology, Neuroscience & Behaviour at McMaster University.  Dr. Goldreich found that, in fact, blind people do not have more sensitivity to touch, but they do feel things faster, especially those who have been blind since birth.  In an experiment comparing people blind from birth, people who've lost their sight more recently, and fully sighted people, he found that they all had equal facility discriminating very small "taps" on their fingers.  But when taps came very close together in time, less than a tenth of a second, those people blind from birth were much better at telling the taps apart.  Those who were best at this were also those who could read braille the fastest.

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Moths Mimic Bats
DogbaneTigerMoth.jpg Dogbane Tiger Moth, courtesy Heather Procter

Echolocation in bats is well documented, but it seems the Toxic Dogbane Tiger Moth is fighting back with its own ultrasonic strategy.  When a bat has the moth on its radar, the moth can detect the frequency of the predator's echolocation.  The Tiger Moth can then assess the risk, based on how close it judges the bat to be, then alter its behaviour accordingly.  The moth sends out clicking sounds of its own that jam the bat's signals.  According to Dr. John Ratcliffe, a Canadian biologist at the University of Southern Denmark in Odense, one of two things happens.  Either the bat becomes confused by the bat-like sounds coming from the moth and aborts the attack, or it associates the clicking sound with the fact that the Tiger Moth is, in fact, toxic, and will make the bat sick.

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Untangling the Heliosphere
heliosphere.jpg The Heliosphere, courtesy NASA

NASA's Interstallar Boundary Explorer, or IBEX, has been observing the outer edge of the solar system for two years now.  This bubble, called the heliosphere, is created when the solar wind from the sun encounters the particles in the interstellar medium.   IBEX has already surprised astrophysicists by showing that the heliosphere is squashed by the galaxy's magnetic fields, and has an intense, knotted ring around it that they're still trying to explain.  Now, however, according to Dr. David McComas, IBEX Principal Investigator and the assistant vice-president for space science and engineering for the Southwest Research Institute in San Antonio, Texas, they've discovered something even more surprising.  The heliosphere, and especially its knotted "ring", seems to change and evolve very quickly - over a period of months, as it passes through an interstellar medium that only really changes over millennia.

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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0