While EBF, or Ecstatic Bike Face, can happen at any time of year in the right conditions, on Ocracoke it is most common as a seasonal syndrome. The afflicted are easily recognizable by enormous smiles they are unable to erase while biking through the village.

Those who have caught EBF report sensations of freedom, surges of joy, and renewed feelings of a youthful sense of playfulness. Adults who escape the petty tyrannies of family vacation are most likely to fall victim, say researchers.

"My in-laws had taken the kids to get ice cream, and my wife was happy with her book, so I decided to take a bike ride," explained Jim Stone of Lancaster, PA. "Next thing I knew, I was cruising down back road, watching the evening light filter through the live oaks, and I was overcome by this feeling of incredible calm and tremendous happiness. I couldn't stop smiling this huge shit-eating smile, and even when I was aware of what a maniac I looked like, I couldn't stop."

Mr. Stone said that, at one point, he even tried to pedal the bike with no hands. 

It is less common to catch EBF when biking with others, and almost impossible to experience when your own children are wobbling beside you. 

Rates of EBF spike during sunny, calm days, but Dr. Erin Baker, the medical director of Ocracoke Health Center, reports that from time to time, a cyclist caught in a sudden downpour will experience a rarer form of EBF that is accompanied by a rush of adrenaline. 

A server who lives on the island says she has been noticing EBF victims for years.

"Often, when I'm riding my own bike to work, I pass someone coming in the other direction like they have no care in the world, smiling like they've just discovered the secret to the universe, and they're all alone on some crappy rental beach cruiser," said Penny Yarborough. "It almost always makes me smile too, so I guess EBF is catching."

The dopamine wash that leads to EBF so far seems to cause no long-term damage to the host humans, though it is connected to an interest in longer and more frequent vacations on Ocracoke, scientists have shown.