Amanda Ripley Author of The Unthinkable

I just finished up a week-long fellowship in Palo Alto (Thank You Stanford!). The university is so beautiful and the weather so ridiculous that you wonder how it can possibly qualify as a school—let alone one of the best schools in the world.

But OK, let’s accept that it is. So one of the things that struck me while I was out there was how cavalier people are with their most valuable asset. Everyone out there rides a bike, which is cool. It is actually a challenge to drive or walk on campus and not collide with a bike. But I was amazed to see that pretty much no one wears a helmet. “Once in a while you’ll see a grad student wearing a helmet,” one professor told me. But the vast majority of the thousands and thousands of bikers whizzing past cars, trucks and other bikes all day long are helmet-less. I know I’m a huge nerd to be thinking about this, but seriously, there is something interesting here.

I ride a bike to work most days. Mostly I love it because it is the fastest way to get around and I can count it as exercise if I get really busy. But I have gotten so used to wearing a helmet that I no longer think it is nerdy. I just don’t think about it at all.

Meanwhile, in Palo Alto, you have about 15,000 people working really hard and paying a lot of money to get a degree. These are people whose main advantage in the world resides in their heads. They are smart and ambitious, it’s fair to say, since Stanford only accepts 8% of the kids who apply.

The university has gone to great lengths to make biking safer (“Meet Sprocket Man, the superman of bicycle safety!” Yes, true story!), but there is a powerful no-helmet culture—even among hardcore geeks (and I saw a lot of them). It’s kind of fascinating, when you think about it. It’s like watching a bunch of aspiring supermodels eat ice cream and fries between posture classes.

Now, some people will argue that helmets don’t make you safer, and there is clearly a dearth of good controlled studies on this (to read more about this, check out this study of what happened after certain countries made helmets mandatory). But it’s also true that the vast majority of people who die in bike accidents are not wearing helmets—and they die from head injuries.

Two months ago, a student named Yichao Wang was hit by a car on Stanford’s campus as he biked home at night. He was thrown 128 feet into an intersection after he failed to yield to a Honda Civic, the police would later conclude. He was not wearing a helmet. He suffered critical brain injuries and spent the next 16 days in a coma. Wang was a Ph.D. student from Singapore who was studying how membranes can absorb pharmaceutical residue during the wastewater treatment process. His family flew in from China and held a vigil at his bedside at Stanford Hospital. He died on Feb. 19.