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Your Bones Are Electric (Sometimes)

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Electricity is all around us. It’s in the wires in our walls, and in the atmosphere. It’s in our phones, our cars, and, these days, our books. But it’s also hiding in a very unexpected place: our bones.

It’s called piezoelectricity, which translates to “electricity by pressing or squeezing.” Brothers Paul-Jacques and Pierre Curie—yes, that Pierre Curie—first coined the term to describe the electricity they saw in compressed quartz and tourmaline crystals.

Basically, piezoelectricity is a way of converting mechanical energy into electricity. Pressure disrupts the balance of an object’s electrical charges. One side of a crystal takes on a positive charge, and the other side becomes negative, which makes it a sort of microscopic battery.

This doesn’t work on everything (stop squeezing your cat, please), only certain crystals. But you’d be surprised how many things those crystals make up, and how useful they can be. 

Piezoelectricity is the force that allows voice recognition software to turn sound waves into signals your computer can use. It’s the reason quartz watches are so accurate, and the force that transforms the grooves on a vinyl LP into music we can hear. We can thank piezoelectricity for cigarette lighters, microphones, gas grills, ultrasound technology, and even potato guns. But its effects don’t stop with appliances; piezoelectricity has been found in all kinds of organic materials, from silk and wood to arteries, tendons, and bone. 

Yes, you have crystals in your bones. Our skeletons are made of both hard and soft tissue. The rigid parts that hold us up are composed of crystals of calcium phosphate, also known as bone salt.

Japanese scientists first found evidence of piezoelectricity in human bone in the late 1950s. In the nearly six decades since, their experiments have been replicated and their results validated. Our bones definitely can hold a charge—and that works to our advantage. 

As it turns out, bone responds pretty well to a little jolt of electricity. Electrical stimulation encourages bones to grow and heal, a fact that’s now being exploited by orthopedic surgeons. Our bones are living, changing objects, endowing the body electric with their odd little spark.

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People Listen (and Remember) Better With Their Right Ears, Study Finds
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If you’re having trouble hearing in a noisy situation, you might want to turn your head. New research finds that people of all ages depend more on their right ear than their left, and remember information better if it comes through their right ear. The findings were presented at the annual meeting of the Acoustical Society of America in New Orleans on December 6.

Kids’ ears work differently than adults' do. Previous studies have found that children's auditory systems can’t separate and process information coming through both of their ears at the same time, and rely more on the auditory pathway coming from the right. This reliance on the right ear tends to decrease when kids reach their teens, but the findings suggest that in certain situations, right-ear dominance persists long into adulthood.

To study how we process information through both our ears, Auburn University audiologists brought 41 adult subjects (between the ages of 19 and 28) into the lab to complete dichotic listening tests, which involve listening to different auditory inputs in each ear. They were either supposed to pay attention only to the words, sentences, or numbers they heard in one ear while ignoring the other, or they were asked to repeat all the words they heard in both ears. In this case, the researchers slowly upped the number of items the test subjects were asked to remember during each hearing test.

Instructions for the audio test read 'Repeat back only the numbers you hear in the right ear.'
Sacchinelli, Weaver, Wilson and Cannon - Auburn University

They found that the harder the memory tests got, the more performance varied between the ears. While both ears performed equally when people were asked to remember only four or so words, when the number got higher, the difference between their abilities became more apparent. When asked to only focus on information coming through their right ear, people’s performance on the memory task increased by an average of 8 percent. For some people, the result was even more dramatic—one person performed 40 percent better while listening with only their right ear.

"Conventional research shows that right-ear advantage diminishes around age 13, but our results indicate this is related to the demand of the task,” one of the researchers, assistant professor Aurora Weaver, explained in a press release. In other words, when the going gets tough, the right ear steps up.

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Pigeons Are Secretly Brilliant Birds That Understand Space and Time, Study Finds
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Of all the birds in the world, the pigeon draws the most ire. Despite their reputation as brainless “rats with wings,” though, they’re actually pretty brilliant (and beautiful) animals. A new study adds more evidence that the family of birds known as pigeons are some of the smartest birds around, as Quartz alerts us.

In addition to being able to distinguish English vocabulary from nonsense words, spot cancer, and tell a Monet from a Picasso, pigeons can understand abstract concepts like space and time, according to the new study published in Current Biology. Their brains just do it in a slightly different way than humans’ do.

Researchers at the University of Iowa set up an experiment where they showed pigeons a computer screen featuring a static horizontal line. The birds were supposed to evaluate the length of the line (either 6 centimeters or 24 centimeters) or the amount of time they saw it (either 2 or 8 seconds). The birds perceived "the longer lines to have longer duration, and lines longer in duration to also be longer in length," according to a press release. This suggests that the concepts are processed in the same region of the brain—as they are in the brains of humans and other primates.

But that abstract thinking doesn’t occur in the same way in bird brains as it does in ours. In humans, perceiving space and time is linked to a region of the brain called the parietal cortex, which the pigeon brains lack entirely. So their brains have to have some other way of processing the concepts.

The study didn’t determine how, exactly, pigeons achieve this cognitive feat, but it’s clear that some other aspect of the central nervous system must be controlling it. That also opens up the possibility that other non-mammal animals can perceive space and time, too, expanding how we think of other animals’ cognitive capabilities.

[h/t Quartz]

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