Hello again, User Friendly fans! This will be my last newsletter of the year. In addition to the upcoming holiday break, my wife and I are expecting our second daughter to arrive any day now. I’ll be back in your inbox the first week of January, slightly sleep deprived but full of joy!
—Adam
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A couple of months ago, I stopped doing something I really enjoy. I quit podcasts. It was supposed to be a short-lived experiment: One month without The Daily or Decoder Ring or that one nerdy show about civilizations ending or any other podcast. It’s been nearly three months now, and I haven’t fully gone back to my old habits. In fact, I don’t think the way I consume media will ever be the same.
That podcast fast turned into a feature in the latest issue of The Highlight, a digital magazine Vox produces in partnership with Apple News. This week, I’m offering User Friendly subscribers a gift link to that story, which is currently available only to Vox Members and Apple News+ subscribers. I also wanted to give you a behind-the-scenes look at how the story came together as well as some details that didn’t make it into the final draft, in part because the ideas were so big they deserved a piece of their own.
Your brain on podcasts
One day I walked into Vox’s office in New York City feeling behind. A deadline was looming, and I’d hoped to sketch out an outline for a story on the subway but — as I always did while on the subway — had also decided to listen to a podcast. When I got to the office, I had no outline, and I doubt I could’ve recalled what the podcast was about. “Is it possible to listen to too many podcasts?” I asked my editor before sitting down. She told me to tell her more, and the next thing I knew I had my next assignment.
Two desks down was Byrd Pinkerton, a host from the Vox podcast Unexplainable. She latched onto this question and started asking me questions as podcast hosts do. Before long, she’d challenged me to quit podcasts for a week and let her record my conversations with neuroscientists, psychologists, and other researchers, who could explain what’s happening to my brain when I do listen. Maybe we’d make a podcast episode about quitting podcasts.
Without spoiling the whole story, I’ll just tell you that what happens to your brain on podcasts is very explainable. When you’re listening to a podcast and doing literally anything else, you’re trying to multitask, which your brain cannot do. What you’re actually doing is rapidly task-switching, and because you’re not focusing on doing one thing, you’re doing everything more poorly.
“Our brains can only do one cognitively demanding task at a time,” Earl Miller, a neuroscientist at MIT, told me. “So if you're trying to pay attention to a podcast and trying to write an email, those kinds of things are both cognitive demanding, and they will interfere with one another.” All of the scientists I talked to said some version of this.
The answer to a related question that came up in every interview was less clear: Why is it easier to focus when I’m listening to music? (I’m doing it right now, as I type out this cognitively demanding newsletter, in fact.) What happens to my brain on music? What about noise or just the din of the modern world?
Your brain on information
Dr. Alexander Huth is a Berkeley neuroscientist with direct knowledge of what happens to your brain on podcasts — and he’s increasingly interested in understanding other signals as well. Nearly a decade ago, he led an experiment that involved playing hours of The Moth Radio Hour to people in fMRI machines. That way, the researchers could see changes in brain activity based on what was happening in each episode. Huth has used a similar setup to collect brain data while people were listening to podcasts. He then used AI to decode that data, effectively turning the subjects’ thoughts into language.
Remarkable as these experiments sound, it’s what Huth is working on next that I can’t stop thinking about. When I asked him why some input — music, noise, din of the modern world — seemed to improve my focus, he brought up “Shannon information.” This is a technical term, named after mathematician and AI pioneer Claude Shannon, that refers to how predictable or, on the contrary, surprising a message is. “If you hear a hum that’s always the same pitch and volume, that’s perfectly predictable — there’s zero new information coming into your brain there,” Huth said. “But if you hear somebody tell you a story that you haven’t heard before, there is a lot of information.”
Your brain, it turns out, finds ways to tune out the predictable information in order to focus on what’s new. This shows up in speech, as we tend to speed up when we’re saying predictable words but slow down when we get to new concepts. The pattern appears to be universal across languages, too. Even though languages sound different, they appear to communicate the same amount of information, according to a 2019 study published in Science that analyzed speech patterns in 17 languages and found they all deliver information at about the same rate: 39 bits per second, where a bit equals one unit of information. (Shannon introduced the term “bit,” which is a contraction of “binary” and “unit,” and he’s also the guy that Anthropic’s AI assistant, Claude, is named after.)
So what does all this have to do with my habit of listening to movie scores while writing? I’m essentially trying to even out the flow of information going into and out of my head. Huth told me — and he said this was “highly speculative” — that “we have some kind of information rate homeostasis in our brain.”
“Maybe each part of our brain says, ‘I want to be processing information at this rate,’” he said. “If you don’t have incoming information from the outside, then your brain doesn’t just become quiet and stop having information. Instead, you internally generate things to bring this rate back up to some level.”
This is why you might start humming when you’re bored, or in my case, start daydreaming when you’re trying to figure out what to write next. Listening to some ambient music, usually without lyrics, does just enough to maintain my information rate homeostasis. A podcast, which amounts to listening and imagining someone else’s story, simply overloads that homeostasis.
But everyone is different. Byrd, the Unexplainable host, likes to play Rummikub while she listens to podcasts and says the distraction actually helps her absorb the information better. That actually makes sense. Rummikub, which is a numbers-based game, occupies one part of the brain, while listening to the story occupies another. “You could even do pretty complex tasks and listen to a story at the same time,” Huth said, “It’s just they have to involve disjoint sets of neural resources.”
Looking back to the day this story was born, I was actually trying to do at least three complex tasks at once: Write, listen, and ride the subway during rush hour. These days, I’ve switched to music on the train, and I miss my stop less often. I still listen to podcasts occasionally, usually while walking my dog. She’s an aging four-pound chihuahua with little ambition. Everything she does is predictable.
—Adam Clark Estes, senior technology correspondent
