8/23/16 Show feat. Matt Grobis on the emergent properties of groups

Schools of fish, like these and the minnows Matt Grobis studies, display behaviors as a group that they cannot replicate as individuals. Image from: Octavio Aburto at Scripps School of Oceanography, UCSD.

Matt Grobis

This week on These Vibes, Stevie interviewed Matt Grobis,  graduate researcher in the department of Ecology and Evolutionary Biology here at Princeton. Matt is also director and co-founder of Princeton Open Labs which organizes science outreach talks and activities for local schools, and writes for a couple blogs: Highwire Earth, an interdisciplinary blog on sustainable development in our changing and growing society where he’s managing editor and co-founder (Matt and Julio Herrera Estrada, the fellow founder of Highwire, came on TVR2C previously for a short segment where they discussed the site) and The Headbanging Behaviorist, which mixes science, activism, and music (so he fits right in here at These Vibes Are Too Cosmic).

We began our discussion with some of the things animals can do together that they cannot especially do alone. Examples of these are migration and predator evasion. For example, the fish shiners prefer to stay in shadows because that will protect them from predators lurking above, but – as Matt discusses in the show – they can’t see the gradients in light well, and thus have difficulty find the shadows unless they’re in a group. Individuals could measure the light level where they were and would change their speed to match it, but they couldn’t actively move to darker areas, so they’re much more likely to be snapped up by a predator. (Here’s the study that found this.)
 Grobis conducts his research both in a lab with actual schools of minnows in a tank and cameras recording their movement (he even has some fake predator concoction to scare the fish), as well as “theoretically” – read: with computer models (like this interesting

School of minnows, from wikicommons.

agent-based model he mentions in the show). Matt’s lab research measures what’s called the “startle.” This is the wave that passes through a school of minnows, for example, when they are, well, startled. In the show Matt also calls this a “cascade.” (Here’s the original paper on startles , also featured in Cell, that Matt’s research is building on.) Matt is seeing if the mechanisms by which the cascade spreads hold up when there’s elevated perception of risk in the environment. Preliminary results indicate that under increased perception of risk, startles might spread a bit differently!

As an example of interesting group behavior, Matt later discussed a specific study (“Uninformed individuals promote democratic consensus in animal groups”, Couzin et al. 2011) that was done with schools of fish. In this experiment the group cannot break apart, but part of the group wants to go towards a blue stimulus and another part really wants to go towards yellow – the behavior that emerges is interesting and seems very relevant to human situations we get in to all the time. (Choosing a dinner place in a big group, anyone?) You can take a look at the study here, and read a blog entry in Headbanging Behaviorist where Matt discusses what happened behind the scenes (a kind of “making of” of the study – this will  be much more accessible than reading the paper itself).
After the interview, Matt noted that “one of the reasons Couzin et al. 2011 is so cool is that they started with the models and found the results in that theoretical universe on their computers. Then, they really hammered it home by showing it’s true in the real world too. So it’s more a good example of the power of combining theoretical models with experiments.” How cool!
In the show we received some excellent listener questions. One listener asked whether Matt’s research on the behaviors of groups could be used to control humans. From this we determined that maybe “control” was a bit strong, but that perhaps this group research could help us better guide traffic, be it in a street or a busy transit hub like an airport. Remember, “ants don’t have traffic jams.”
(In this part Matt mentioned research on autonomous robots that his adviser Iain Couzin is working on. It’s sponsored by the Office of Naval Research and is shared with Mechanical and Aerospace Engineering Professor Naomi Leonard.)
If you live in the Princeton area, and especially if you have school-aged children, please check out Matt Grobis’s side project Open Labs!
The great minnow.

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8/16/16 Show feat. author Brad Watson on his new novel, Miss Jane


Featured image: A tomato hornworm being devoured, “casually,” by wasp larvae in their cocoons. Courtesy Wikimedia Foundation and the penultimate chapter of Miss Jane.

We were fortunate this week to air a phenomenal interview with author Brad WatsonProfessor of Creative Writing at University of Wyoming and acclaimed novelist with two short-story collections and two books. His newest work, Miss Jane, just came out in July 2016, so we took the opportunity to ask Brad about the writing process and how he came to think of the world from Jane’s perspective.  The conversation meanders through questions of gender identity, nature and Southernness, and feeling like the odd one out–it’s a thoroughly fascinating talk, so listen to the audio above and don’t just take my word for it.

missJane.jpgThe novel centers around Jane Chisolm, born on a cattle farm in 1915 Mississippi. From her first hours, Jane is defined by a birth defect: it leaves her incontinent and incapable of sex. Modern surgical technology could remedy a condition like this immediately. But in her day and age, Jane is left without recourse. The novel captures its heroine’s full arc, and over its course Brad explores the many consequences of Jane’s affliction.

A character like Jane is hard to relate to, especially for an author writing a century later with little to go off of but a childhood in the South. The story’s inspiration comes through a great-aunt, a mysterious figure that Brad only met once and knew mostly through old photos. Because of the lack of information, the novel took 13 years to write, only beginning seriously in 2013 when Brad connected his great-aunt’s story with a plausible medical condition that made her feel more concrete.

Even then, Brad couldn’t get a good look at who Jane might have been as a person without developing the story’s supporting characters. A small cast of dynamic personalities, including Jane’s nuclear family and the doctor that treats her, bolster the novel and give Brad different lenses into seeing Jane. He makes a point that characters shouldn’t be written into a story unless they help the reader understand the protagonist–and in this sparse collection of characters, Brad’s writing makes everyone seem like a piece of the puzzle, not just illuminating Jane but giving shape to the novel’s central conundrums.

The writing stands out for its perceptive descriptions of the natural world. Jane finds solace in the Southern forest near her home, where Brad remarks that everything is strange if you look hard enough: from mushrooms in the soil to fish that sift water through their gills to breathe. To a character that feels like an outsider in the human world, the oddities of wilderness are a comfort.

We talk a while about the strangeness of the South, too. It’s a place Brad doesn’t think

“Meditating” : Evocative pencil artwork from Mary Jane Parker, another artist focusing on nature and the South.

he’ll be able to get over, even now that he lives in Wyoming and only visits his childhood home occasionally. More than anywhere else in the US, the South maintains its own mentality, and the roots of it are deeply twisted around a history that Southerners spend their lives trying to process. Brad doubts he can stop writing about the region, since he has such a backlog of stories it has inspired.

On my mind as I read Miss Jane was the plot’s intricate connections with the American dialogue on gender identity. Brad clarifies that he began the novel years before this debate became mainstream, though he did wonder about Jane’s possible intersexuality in the course of defining her as a character. In the end, he writes Jane as a heterosexual female–which is fitting for the times, since 1920s Mississippian culture had no notion of the gender spectrum. Still, the foil between Miss Jane and our modern conversation is an important one, since Jane’s life was severely affected by a lack of medical technology that nowadays gives us the power to perform, say, sex reassignment surgeries.

I can’t recommend this book highly enough–not only is it an entertaining and beautiful read, but the wholeness which Brad builds into his characters is obvious from the start. For more information on the rest of his book tour or on Miss Jane, visit Brad’s website here.

Our show-closer comes from a listener who asked, semi-seriously, if the grass is truly always greener on the other side. Semi-seriously, we answer: the phrase came first from the Billy Jones tune above. Statistically, of course, your grass is probably about as green as everyone else’s, but Stevie brings us back to the real meaning of the phrase (comparing your well-being to others) and how it might explain Trump supporters.

As always, the playlist is on WPRB.com or below.

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8/9/16 Show feat. Dr. Edgar Choueiri on plasma propulsion and 3D sound engineering


Featured image: NASA’s Dawn mission, currently orbiting its second destination in the Asteroid Belt, is equipped with an ion thruster to boost its efficiency and make visiting multiple bodies possible. Courtesy NASA’s JPL.

Dr. Edgar Choueiri of Princeton’s Mechanical and Aerospace Engineering is on the air this week, and he brings his innovative physics applications to our conversation. Hear all about the dramatic Hall thruster technology as a method of space propulsion, and then get blown away by the idea of virtual-reality 3D sound. Throughout the interview, I had the feeling that science fiction was coming to life out of Edgar’s research, so check out the full recording to be really amazed at where technology is headed.

A Saturn Five rocket lifts off (from NASA).

Edgar began his work at Princeton researching space propulsion. For many years, we’ve had a solution to this problem: chemical thrusters, which burn massive amounts of fuel to blast rockets up into space. However, it’s clear that this method is horribly inefficient. Just look at a typical Saturn 5 rocket, where a tiny payload sits on a massive container of fuel. All chemical thrusters work this way, since the amount of rocket fuel needed to lift a load out of Earth’s gravity is about ten times the mass of the load. Since combustion ejects particles at a particular speed of a few kilometers per second, we’re stuck with this inefficiency as long as we burn chemicals to get into space.

The most obvious way to improve this picture is by forcing particles out of a spaceship at higher speeds. We can achieve this acceleration by propelling the rocket with plasma, a charged gas that responds to electric fields. By making an electric field–which is easy to do with some solar panels and a metal grid–the spacecraft ejects plasma at any speed we like, which can drastically improve the thrust efficiency. Edgar makes an analogy of driving across the country: a chemical rocket is so inefficient that you need to stop for gas tens of times between New York and California, whereas a plasma thruster would let you go the whole way without refueling.

A Hall thruster on display from U. Michigan’s PEPL.

In some ways, we’re stuck with chemical rockets, because plasma engines aren’t good enough to get us out of Earth’s atmosphere. But once a spacecraft is in orbit, Edgar’s thrusters make the next steps cheaper and quicker. For example, a trip to Mars might take nine months with chemical fuel, but only three months with plasma fuel.

Edgar has seen a lot of progress in implementing these new technologies over the years. When he began graduate school, ion thrusters were science fiction; now they’re used widely by NASA and private companies. A newer design, the Hall thruster, uses clever arrangements of electromagnetic fields to keep particles confined and boost efficiency. And as Edgar’s group improves the Hall thruster design, it’s also seeing more use in space–perhaps an explosion in their use is coming, as Edgar hints at by mentioning SpaceX’s interest in the technology.

Aside from space propulsion, Edgar has another specialty that’s seeded a second laboratory at Princeton: 3D audio engineering. When we hear sounds, our brains can pinpoint their origin beneath our conscious awareness. An airplane overhead, a voice behind us… we could point to a sound’s source even if our eyes were closed. Unfortunately, reproduced sound from speakers or headphones has lost this spatial signature. To Edgar, hearing the breadth of a symphony confined to the location of a speaker isn’t authentic. That’s why he’s working to restore three-dimensionality to recorded audio.

Our ears can find a sound’s source from three cues. The first is the small delay between sounds reaching your right ear and your left ear, or the inter-aural time difference. Second is the loudness of sound in one ear compared to the other, or the inter-aural level difference. Lastly, the specific shape of your earlobes funnels sounds to your eardrums, and this personalized filter lets our brain know whether a sound is near or far, above or below.

A simple way to record in 3D: use a dummy head. From Hooke Audio.

Since the 1960s, we’ve mastered the first two cues, typically by recording sounds from two microphones on the sides of a dummy head. In fact, these “binaural” recordings are enough for about a third of the population: the inter-aural time difference and inter-aural level difference will convince them that sounds are happening in 3D. For the rest of us, though, the unique shapes of our own ears affects our spatial perception of sound. Making a recording that everyone will perceive as truly 3D means we need to record audio specially for each pair of ears. Further, your brain expects sound to move from right to left when we shake our heads: but recordings don’t move along with you. So, there are a lot of obstacles to perfecting 3D audio for everyone.

Edgar’s group is fighting off these remaining problems one at a time. One of his students, Joseph Tylka, makes facial recognition software to track head movements and modify audio playback in real time, so that the 3D experience is uninterrupted when you shift around. Another student, Rahulram Sridhar, is developing a method to tune 3D audio to your earlobes with quick image analysis. Finally, the group is working on sound wave cancellation, so that different areas in space would receive completely different soundwaves from the same set of speakers.

All this innovation sounds far fetched, but these projects are moving along quickly–and Edgar foresees a lot of short-term applications. Imagine four friends sitting in a car, all listening to the same sound system but all hearing different tracks individualized to their ears. Everyone can navigate through a virtual 3D sound field, listening to hyperrealistic concerts from the mezzanine or from behind the stage according to their wishes. If Dr. Choueiri’s lab succeeds, we could have sound systems like this in the very near future.

For more information on present-day technology for 3D sound, check out Jambox and LiveAudio, which Dr. Choueiri demonstrates during the interview.

The playlist can be found at WPRB.com or below.

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8/2/16 Show feat. Sam McDougle on learning and motor skills (re-aired) + dynamo in the Earth’s core


Featured Image: These fMRI images from Jean Gotman at McGill highlight a small part of the brain, because it’s statistically more active than it was at some other moment. Remember: the other 90% of the brain is still actively in use!

For this week’s show, we replayed an earlier interview from Sam McDougle, a graduate student in the Department of Neuroscience at Princeton. He and Stevie dive into his research on motor skills, learning, and the brain, and they debunk the ever-popular myth that we only use 10% of our neurons at once. After the interview, I describe the Earth’s dynamo problem and some new research from Osaka University that raises more puzzles than it solves.

Sam and the rest of the Taylor Lab want to know what the brain is doing when we learn new skills. We’re all used to the feeling when something clicks and a skill becomes easy for us: riding a bike, cutting with scissors, and typing have all become automatic for us eventually. But initially, developing a new task into a skill requires practice. Building up muscle memory and neuronal networks that fit the task is a long process in the brain, and it’s hard for science to unveil completely. As Sam says, researchers rarely find conclusions, they just scramble for hints until they can piece together ideas about the truth.

To study the learning process, Sam first experimented on mice, fitting them with brain electrodes and having them repeat behaviors. But even though the brain fundamentals are very similar between mice and humans, the complicated tasks that people have to learn go beyond the range of mouse-science. Now, Sam brings in human volunteers to study instead, and relies on less invasive data collection (like fMRI instead of electrodes inside the skull).

Fancy brain imaging from Princeton Neuroscience Institute.

To be clear, there’s a lot going on in the brain at once. An fMRI scan may just show a small blob of color somewhere in the brain, but this highlight just shows a place where the brain was more active than it used to be before the experiment. Sam’s brain scans might showcase, for example, neural areas that handle muscle memory; but even as these particular brain sections are especially active, the rest of the neurons are still abuzz. The myth that “we only use 10% of our brains” might have originated in Dale Carnegie’s famous self-help book, How to Win Friends and Influence People–and even there, it only appears as a misattributed quote in the foreword. So don’t believe the rumors, because your whole brain is always hard at work.

Testing hypotheses on human subjects is no easy matter. For one, Sam can’t have people learn nuanced skills in the experiment. To teach thirty subjects to play the violin and measure their brainwaves as they do it will take months, will cost a lot, and won’t be very repeatable from person to person. Instead, Sam and his colleagues have to think of tasks that are complicated enough that we must learn them, but are still so simple that the study can proceed quickly and repeatably.

One result of  the studies so far is the demonstration of “implicit” versus “explicit” motor skill learning. Teaching someone to snowboard might involve phrases like “keep your weight on your back leg” or “dig in to brake;” these “explicit” instructions give the learner some reference for improving quickly. But, verbal commands alone can’t do the whole job, since most of the learning comes from testing behaviors out.  Imagine reading a book about swimming and then jumping in the pool for the first time: you’d still have a lot to figure out about treading water. The implicit skills you develop from trying, failing, and trying again are ultimately the backbone of mastering a task. Sam’s results show that implicit and explicit learning are stored in different parts of the brain, and the research is still attempting to find connections between the two.

Sam closed the interview with a bit about his own musicianship. Among many projects, he plays and records his own music as Polly Hi. I anachronistically played a song from Deceleration, Sam’s newest album, which actually came out months after this interview last year.

I ended the show with a major problem in astrophysics and geology: why is the Earth still magnetized? From what we know about currents and electricity, magnetic fields should decay over time and eventually die out. However, the Earth has a strong magnetic field: it keeps us safe from the solar wind, helps maintain our atmosphere, and brings the auroras to the poles. So, something doesn’t add up. The Earth’s core must have some net current or flow that maintains the magnetic field over billions of years.

Scientists at Osaka University just did an experiment to simulate the Earth’s core and resolve this issue once and for all. The core is made of nickel and iron, so the group put iron wires into a diamond anvil–a device that generates gigantic pressures on a tiny area in a lab. By heating the wires with lasers and putting a current through them, the scientists measured how well iron can conduct a current in the middle of the Earth. Based on their measurements and how strong the Earth’s magnetic field is, the Earth should be about 700 million years old. The problem: it’s much, much older than that (over 4 billion years!).

earths layers
The Earth, decomposed into its parts. Don’t let pictures like this fool you into thinking we have it all figured out!

What does this puzzling result tell us? Largely, it’s that there are properties of the Earth’s core that we don’t understand at all. You might think that by being space explorers and mastering fracking and plate tectonics, we’d have figured out the composition of the Earth by now. Unfortunately, while we do understand the crust and mantle of our planet, the nickel-iron core is inaccessible to direct measurement. We can study waves that pass through the middle of the Earth, and we can study high-temperature high-pressure materials in the lab, but understanding the complex motions at the middle of the Earth is probably a long way away.

As always, the playlist is on WPRB or below.

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