Short Wave

Why do we kiss? It's an evolutionary conundrum

The evolutionary purpose of kissing has long eluded scientists. Smooching is risky, given things like pointy teeth, and inherently gross, given an estimated 80 million bacteria are transferred in a 10 second kiss. And yet, from polar bears to humans, albatrosses and prairie dogs, many animals kiss. So, what gives? Evolutionary biologist Matilda Brindle [https://matildabrindle.weebly.com/] tells us the sordid details driving this behavior, what distinguishes different kinds of kissing and whether culture has anything to do with why people kiss. Interested in more of the science behind love and connection? Email us your question at shortwave@npr.org [shortwave@npr.org]. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave [http://plus.npr.org/shortwave]. Learn more about sponsor message choices: podcastchoices.com/adchoices [https://podcastchoices.com/adchoices] NPR Privacy Policy [https://www.npr.org/about-npr/179878450/privacy-policy]

AI is great at predicting text. Can it guide robots?

It seems like artificial intelligence is everywhere in our virtual lives. It's in our search results and our phones. But what happens when AI moves out of the chat and into the real world? NPR science editor and correspondent Geoff Brumfiel [https://www.npr.org/people/279612138/geoff-brumfiel] took a trip to the Intelligence through Robotic Interaction at Scale Lab at Stanford University to see how scientists are using AI to power robots and the large hurtles that exist for them to perform even simple tasks. (encore) Read Geoff's full story [https://www.npr.org/2025/03/17/nx-s1-5323897/researchers-are-rushing-to-build-ai-powered-robots-but-will-they-work]. ---------------------------------------- Interested in more AI stories? Email us your ideas at shortwave@npr.org [shortwave@npr.org].Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave [http://plus.npr.org/shortwave]. Learn more about sponsor message choices: podcastchoices.com/adchoices [https://podcastchoices.com/adchoices] NPR Privacy Policy [https://www.npr.org/about-npr/179878450/privacy-policy]

The physics of the Winter Olympics

Watching a ski jumper fly through the air might get you wondering, “How do they do that?” The answer is – physics! That’s why this episode, we have two physicists – Amy Pope [https://www.clemson.edu/science/academics/departments/physics/about/profiles/amyj], a physicist from Clemson University and host Regina G. Barber [https://www.npr.org/people/1082526815/regina-g-barber] – break down the science at play across some of the sports at the 2026 Winter Olympics. Because what’s a sport without a little friction, lift and conservation of energy? They also get into the new sport this year, ski mountaineering - or “skimo” as many call it - and the recent scandal involving the men’s ski jump suits.  Interested in more science behind Olympic sports? Check out our episodes on how extreme G-forces affect Olympic bobsledders [https://www.npr.org/2026/02/04/nx-s1-5692856/olympics-bobsled-skeleton-luge-brain-health], the physics of figure skating [https://www.npr.org/2022/02/04/1078181430/the-physics-of-figure-skating] and the science behind Simone Biles' Olympic gold [https://www.npr.org/2024/08/02/1198910473/simone-biles-olympics-gymnastics-medals-physics].  Also, we’d love to know what science questions have you stumped. Email us your questions at shortwave@npr.org [shortwave@npr.org] – we may solve it for you on a future episode! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave [http://plus.npr.org/shortwave]. Learn more about sponsor message choices: podcastchoices.com/adchoices [https://podcastchoices.com/adchoices] NPR Privacy Policy [https://www.npr.org/about-npr/179878450/privacy-policy]

These bacteria may be key to the fight against antibiotic resistance

In 1928, a chance contaminant in Scottish physician Alexander Fleming’s lab experiment led to a discovery that would change the field of medicine forever: penicillin. Since then, penicillin and other antibiotics have saved millions of lives. With one problem: the growing threat of antibiotic resistance. Today on Short Wave, host Regina G. Barber [https://www.npr.org/people/1082526815/regina-g-barber] talks to biophysicist Nathalie Balaban [https://nano.huji.ac.il/people/nathalie-questembert-balaban] from Hebrew University about the conundrum — and a discovery her lab has made in bacteria that could turn the tides. Check out our episodes on extreme bacteria in Yellowstone [https://www.npr.org/2025/02/05/1229167010/yellowstone-bacteria-hot-springs-microbes-relationship] and the last universal common ancestor [https://www.npr.org/2025/01/17/1225172117/life-species-luca-ancestors].  Interested in more science behind our medicines? Email us your question at shortwave@npr.org [shortwave@npr.org]. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave [http://plus.npr.org/shortwave]. This episode was produced by Berly McCoy, edited by our showrunner Rebecca Ramirez and fact checked by Tyler Jones. Jimmy Keeley was the audio engineer. Learn more about sponsor message choices: podcastchoices.com/adchoices [https://podcastchoices.com/adchoices] NPR Privacy Policy [https://www.npr.org/about-npr/179878450/privacy-policy]

Babies got beat: Why rhythm might be innate

Rhythm is everywhere. Even if you don’t think you have it, it’s fundamental to humans’ biological systems. Our heartbeat is rhythmic. Speech is rhythmic. Even as babies, humans can track basic rhythm. Researchers wanted to find out if there were more layers to this: Could babies also track melody and more complicated rhythms? So they played Bach for a bunch of sleeping newborns and monitored the babies’ brains to see if they could predict the next note. What they found offers clues about whether melody and rhythm are hard-wired in the human brain or learned over time. We also get into what powers the eating habits of some snakes and chameleons, and insights into the role of sleep in problem-solving. Have a scientific question you want us to answer? Email us at shortwave@npr.org [shortwave@npr.org]. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave [http://plus.npr.org/shortwave]. Listen to Short Wave on Spotify [https://n.pr/3HOQKeK] and Apple Podcasts [https://n.pr/3WA9vqh].  This episode was produced by Jordan-Marie Smith and Rachel Carlson. It was edited by Rebecca Ramirez and Christopher Intagliata. Tyler Jones checked the facts. The audio engineers were Jimmy Keeley and Hannah Gluvna.  Learn more about sponsor message choices: podcastchoices.com/adchoices [https://podcastchoices.com/adchoices] NPR Privacy Policy [https://www.npr.org/about-npr/179878450/privacy-policy]