Learn how researchers test drugs for deadly diseases like COVID-19 (without exposing participants); how Fannie Farmer transformed cooking from folk art into science; and how the Shepard scale audio illusion makes it sound like a tone is rising forever.
Learn how researchers test drugs for deadly diseases like COVID-19 (without exposing participants); how Fannie Farmer transformed cooking from folk art into science; and how the Shepard scale audio illusion makes it sound like a tone is rising forever.
Safety in drug trials by Ashley Hamer (Listener question from Habib)
How Fannie Farmer transformed cooking from folk art into science by Cameron Duke
The Shepard scale is an audio illusion that sounds like a tone is rising forever by Ashley Hamer
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/fannie-farmer-created-the-modern-cooking-recipe-the-shepard-scale-audio-illusion-and-how-scientists-test-the-covid-19-vaccine
CODY: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from curiosity-dot-com. I’m Cody Gough.
ASHLEY: And I’m Ashley Hamer. Today, we’ll answer a listener question about how researchers test drugs for deadly diseases like COVID-19 — without exposing people to the disease. You’ll also learn about why you can thank Fannie Farmer for basically every recipe you’ve ever cooked; and an audio illusion that sounds like a tone is rising forever.
CODY: Let’s satisfy some curiosity.
We got a listener question from Habib, who writes, “I recently heard about a successful field trial on using pre-exposure prophylaxis (or PREP) for HIV prevention. My question is: How do they do such drug trials without intentionally exposing people to HIV?” Considering the fact that we’re currently racing to develop a COVID-19 vaccine, that is a very well-timed question, Habib!
In a non-medical study — like, say, one where you’re trying to determine the best rain repellant for a car windshield — you’d treat the windshield with different products, then expose it to water and see which one works best. But if you’re developing a drug to protect humans from a potentially deadly, incurable disease, you can’t expose them to that disease. It’s just not ethical. That’s not to say it hasn’t been done with other, curable diseases: vaccines for things like cholera, typhoid, and even influenza have been tested on people who were deliberately exposed to the disease. Those are what you call human challenge trials. But there’s no cure for HIV/AIDS. You just can’t do it.
So instead, researchers start by measuring antibodies in their blood. And in later trials, they just let the participants just live their normal lives. Usually, the researchers give half of them the real drug and half of them a placebo, then wait anywhere from a few months to a few years to see how many people in each group get the disease. If the people taking the real drug contract the disease significantly less often than the people taking the placebo, that suggests the drug is effective. This whole process takes a lot longer than deliberately exposing people to the disease, but it carries a lot less risk for the participants.
And like I said, this has big implications right now when the whole world is waiting for a vaccine that can protect us from COVID-19. At this very moment, more than 165 coronavirus vaccines are in development, and [27] are in human trials. Those trials are using these same methods: giving the vaccine to some people and not others, then seeing how many of each get COVID-19 in the real world. But some scientists are suggesting that we go ahead and expose those participants to COVID-19, just to speed up the process. Others say that even putting aside the ethical implications, some places have such high levels of new infections that doing that probably wouldn’t speed up the process all that much. So for now, we watch and wait. If you want to keep tabs on the process, the New York Times has an excellent Coronavirus Vaccine Tracker that we’ll link to in the show notes. Thanks for your question, Habib! If you have a question, send it into podcast at curiosity dot com or leave us a voicemail at 312-596-5208.
Have you cooked something from a recipe lately? If that recipe told you what temperature to set the oven and the exact measurement of each ingredient — so, like, every recipe — there’s one woman you can thank, and you’ve probably never heard her name. Let me tell you about Fannie Merritt Farmer.
Born in 1857, Fannie Merritt Farmer is known as the woman who made cooking scientific. She was a cooking teacher, writer, and lecturer who was the closest someone could get to being a celebrity chef in the 1800s. She insisted on a scientific approach and precise measurements, which inspired generations of cooks and built a legacy that lives on in every American kitchen.
For all she achieved, Fannie Farmer actually got a pretty late start in her career. She suffered a stroke when she was 16 that left her partially paralyzed and forced her to quit school. She eventually recovered and took a job as a household assistant, which made her realize how much she loved to cook. So at age 30, she became a student again — this time at the Boston Cooking School. She took to the subject matter so well that within a few years she was literally running the place as the school’s director.
To understand Fannie Farmer’s accomplishments, you need to understand what cooking was like in the 1890s. At the time, recipes assumed a certain amount of culinary knowledge. Measurements were usually pretty subjective, too, with recipes often calling for things like “a goodly amount” of molasses, or just telling the reader to bake something without specifying a temperature or a length of time.
Farmer changed all of this. She believed that precise measurements and instructions make for better food. Her 1896 cookbook, called the Fannie Farmer Cookbook, made no assumptions about the reader’s education or skill. As a result, the recipes actually worked, and the cookbook sold 8,000 copies in the first year. It even served as the “go-to” text for such culinary greats as Julia Child.
Fannie Farmer also wrote a lot about the role food plays in health — before nutrition science was a thing. She even became one of the first women to lecture at Harvard Medical School, specifically on the role food can play in fighting disease. Her lectures for the general public were popular enough to be printed in newspapers.
In 1902, she left to open her own cooking school, this one aimed at homemakers. She passed away in 1915, but her cookbook lives on, having sold more than 7 million copies worldwide. By taking a scientific approach, she ended up making cooking accessible to everyone.
If you look at a barber’s pole, it seems like those diagonal stripes are moving upward forever. I mean, you know they can’t be — it’s just a pole with stripes on it. But you get the illusion of something like infinity. Well, there’s an audio illusion that gives that same impression. It’s called the Shepard scale. And filmmakers use it on you all the time to mess with your brain’s expectations. Ready to learn how to spot it?
Here’s an example.
[Shepardscale.wav - 0:11]
Sounds kind of like it rises forever, doesn’t it? But it doesn’t. In fact, it repeated itself halfway through. Wild, right?
The Shepard scale is named after its inventor, Robert Shepard. Shepard isn’t a musician — he’s a cognitive scientist. But in 1964, he published a paper demonstrating a way to generate tones that lead to “a complete breakdown” in a person’s ability to judge whether one pitch was higher or lower than another.
He did this by generating individual tones made up of octaves — that’s a musical term for the higher or lower version of the same pitch. Like, low C is an octave below middle C, which is an octave below high C. Then, he’d play those in a scale — C, D, E, F, G, A, B, and back to C. But as the scale rose in pitch, he’d soften those higher octaves while turning up the lower octaves. Once he got to the end of the scale, then, the ending “C” would be the exact same tone as the starting C, but the listener’s ear had already grabbed onto a lower octave — another stripe on the barber’s pole, if you will — to make it sound like the next logical tone in the scale.
This works going up or down. It also works when it’s not a scale at all, but just one continuous gliding pitch. French composer Jean-Claude Risset [REE-say] built on Shepard’s creation to produce this kind of tone, called a Shepard–Risset glissando.
[DescenteInfinie.mp3 - it’s 1:05 but just cut off wherever you need]
Again, it sounds like it’s falling forever, but it’s not. The octaves that make up the tones are being subtly tweaked to make it sound that way. These illusions take advantage of the fact that we judge musical notes not only by “height,” or how high or low the pitch is, but also by tone, or what note we’re hearing. When you hear a C followed by a D, you expect that D to be higher than the C — so even if it’s an octave lower than the C, your brain thinks “higher.” And that’s what you hear.
Movies use this all the time to create suspense — Christopher Nolan is a particular fan of it. So the next time you hear a tone rising into infinity, you’ll know it’s not: it’s just the Shepard scale taking advantage of your brain’s expectations.
Leave us a voicemail at 312-596-5208!
CODY: Before we recap what we learned today, here’s a sneak peek at what you’ll hear next week on Curiosity Daily.
ASHLEY: Next week, you’ll learn about how humans literally use their noses to navigate;
5 myths about summer dangers;
Whether men really see less mess than women;
The best time of day to exercise;
And more! Okay, so now, let’s recap what we learned today.
[ad lib optional]
CODY: Today’s stories were written by Ashley Hamer and Cameron Duke, and edited by Ashley Hamer, who’s the managing editor for Curiosity Daily.
ASHLEY: Today’s episode was produced and edited by Cody Gough.
CODY: Have a great weekend, try cooking a new recipe, and take a trip to flavor town! Then, join us again Monday to learn something new in just a few minutes.
ASHLEY: And until then, stay curious!