"I would not climb Everest. I have other things to do, but in plain English, I'm also too scared to do it," Wilke said. "But I would do things some mountain climbers would not do, like lecture to 500 undergraduates."
From an evolutionary perspective, Wilke said, risk-taking behavior can be advantageous, particularly in men, because it signals strength and fitness to members of the opposite sex. In line with that theory, a successful Everest climb can convey status and prestige.
"If you said you went to Everest, you by definition climbed the highest mountain available to mankind," he said. "That's a very clear, non-fakable hierarchy. We can be very competitive in nature."
For many people who have topped Everest, though, it's about much more than hubris. Surpassing the "death zone" above 8,000 meters, standing on top of the world and returning home safely is an experience unlike any other.
"It brings into focus what's important to you," said Arnette, who summited Everest on his fourth attempt in 2011. "There are a thousand reasons to turn around and only one to keep going. You really have to focus on the one reason that's most important and unique to you.