On August 7, 1974, Philippe Petit, the French high-wire artist, walked between the Twin Towers of the World Trade Center in New York City. He wore no safety harness and used no ropes.
In 1859, Charles Blondin famously crossed Niagara Falls on a high wire. He managed the feat not once, but 17 times. Once, he carried his terrified manager, Harry Colcord, across the Falls on his back.
But those guys had nothing on a 33-year-old Alex Honnold for daredevilry. With no rope, harness, or safety gear of any kind, Honnold ascended the 101-story Taipei Tower with seeming ease, taking 91 minutes to climb the 1,667 feet to the top. The stunt was broadcast live on Netflix, which dubbed the program "Skyscraper Live."
Alex Honnold taking a selfie at the top of Taipei 101 after free soloing the skyscraper.
— Netflix Sports (@netflixsports) January 25, 2026
UNBELIEVABLE!!! #SkyscraperLIVE pic.twitter.com/czuxYkoVpY
"LOOK MA! NO HANDS!"
No hands is crazy. @AlexHonnold #SkyscraperLIVE pic.twitter.com/twmCSX5nDS
— Netflix (@netflix) January 25, 2026
"So cool." - Alex Honnold while free soloing one of the tallest buildings in the world.
— Netflix Sports (@netflixsports) January 25, 2026
No big deal.#SkyscraperLIVE pic.twitter.com/sJJl10u0CG
Honnold's hands and feet are enormous. The strength in those digits must be phenomenal.
Take a wider look at Alex Honnold’s hands and feet and their incredible proportions
— Mambo Italiano (@mamboitaliano__) January 25, 2026
A legend of our time 🧗 pic.twitter.com/2eD9o19kFW
While no doubt blessed with impressive physical gifts, it's his brain that fascinates scientists.
"Alex Honnold has his own verb. 'To honnold'—usually written as 'honnolding'—is to stand in some high, precarious place with your back to the wall, looking straight into the abyss," writes J.B. MacKinnon in Nautilus.
The verb was inspired by photographs of Honnold in precisely that position on Thank God Ledge, located 1,800 feet off the deck in Yosemite National Park. Honnold side-shuffled across this narrow sill of stone, heels to the wall, toes touching the void, when, in 2008, he became the first rock climber ever to scale the sheer granite face of Half Dome alone and without a rope. Had he lost his balance, he would have fallen for 10 long seconds to his death on the ground far below. One. Two. Three. Four. Five. Six. Seven. Eight. Nine. Ten.
Honnold is history's greatest "free climber," meaning he ascends without safety gear. He's able to do this fearlessly because, literally, he knows no fear.
Jane Joseph, a cognitive neuroscientist, volunteered to begin carrying out fMRIs ("functional magnetic resonance imaging" brain scans) on "high sensation seekers." These are people "drawn to intense experiences and willing to take risks to have them," explains MacKinon.
Psychologists have studied sensation seeking for decades because it often leads to out-of-control behaviors such as drug and alcohol addiction, unsafe sex, and problem gambling. In Honnold, Joseph saw the possibility of a more remarkable typology: the super sensation seeker, who pursues experiences at the outer limits of danger, yet is able to tightly regulate the mind and body’s responses to them. She is also simply in awe of what Honnold can do. She had tried to watch videos of him climbing ropeless, but being a low sensation seeker herself, found them overwhelming.
“I’m excited to see what his brain looks like,” she says, sitting in the control room. “Then we’ll just check what his amygdala is doing, to see: Does he really have no fear?”
The amygdala is often referred to as the most "primitive" part of the brain, but that's not entirely true. It's the part of the brain that deals with basic survival instincts. Is Honnold’s really different from the average person’s? The fMRI should be able to tell her.
Inside the MRI tube, Honnold is exposed to dozens of images—some of them gross (a backed-up toilet), bloody corpses, and a couple of mountain-climbing scenes.
“Maybe his amygdala is not firing—he’s having no internal reactions to these stimuli,” says Joseph. “But it could be the case that he has such a well-honed regulatory system that he can say, ‘OK, I’m feeling all this stuff, my amygdala is going off,’ but his frontal cortex is just so powerful that it can calm him down.”
There's a more fundamental question Ms. Joseph is asking: “Why does he do this? He knows it’s life-threatening—I’m sure people tell him every day. So there may be some kind of really strong reward, like the thrill of it is very rewarding.”
To find out, Honnold is now running through a second experiment, the “reward task,” in the scanner. He can win or lose small amounts of money (the most he can win is $22) depending on how quickly he clicks a button when signaled. “It’s a task that we know activates the reward circuitry very strongly in the rest of us,” Joseph says.
In this case, she’s looking most closely at another brain apparatus, the nucleus accumbens, located not far from the amygdala (which is also at play in the reward circuitry) near the top of the brainstem. It is one of the principal processors of dopamine, a neurotransmitter that arouses desire and pleasure. High sensation seekers, Joseph explains, may require more stimulation than other people to get a dopamine hit.
Joseph asked Honnold what he thought of the photos.
“Those images that you saw are used pretty widely in the field for inducing fairly strong arousal responses,” Joseph replies.
“Because I can’t say for sure, but I was like, whatever,” Honnold says.
Indeed, after studying the scans, Ms. Joseph determined that Honnold had no reaction at all to photographs designed to elicit some kind of response. She even used a "control" subject who took the same scans and saw the same photos.
MacKinon writes, "In the fMRI images of the two men’s responses to the high-arousal photographs, with brain activity indicated in electric purple, the control subject’s amygdala might as well be a neon sign. Honnold’s is gray. He shows zero activation."
“There’s just not much going on in my brain,” Honnold mused, looking at the scans. “It just doesn’t do anything.”
Nowhere in the fear center of Honnold’s brain could the neuroscientist spot activity. This doesn't mean that Honnnold is "fearless." It just means that whatever is happening in his amygdala, it's not showing up in the scans.
Honnold is a unique human being with unique physical gifts and a unique outlook on his daredevil lifestyle. He also seems like the sort of guy you could sit down next to in a bar and talk about anything.
He's bound to make it an interesting conversation.
