“There is already a culture of getting work done here,” Mr. Bacigalupo said. “We might turn the music up a little louder at night, crack open a few beers, but I think it helps that people know you come here to focus and make things.”

One big advantage of the late-night hours is that they are blissfully free of the distractions that clutter the daytime. Even the Web goes quiet. People feel less compelled to check Twitter and Facebook and chat with friends and colleagues via instant message.

“When you don’t have your co-workers constantly interrupting you, fewer friends bored at work and on IM, it’s easier to get things done,” said Montana Low, the chief scientist at RescueTime, which makes productivity software. “A lot of people have problems with this type of distraction, and everyone is looking for ways to get a little more out of their day.”

On an average workday, most people visit about 40 Web sites, ranging from social networking hubs to shopping and entertainment portals, according to RescueTime, which studies the habits of the 200,000 people who have downloaded its software. The frequency with which people jump around online slows by nearly half during the early hours of the morning, Mr. Low said.

But preferring to work at night might go beyond a need to escape distractions. Some people are hard-wired to perform better as it gets later, said Michael Thorpy, director of the Sleep-Wake Disorder Center at the Montefiore Medical Center in the Bronx.

“Our circadian timing of sleep is affected by genetics, and people all differ,” he said.

Mr. Thorpy said many people experience surges of alertness two to three hours before they fall asleep  ideal for powering through some unfinished business.

“If it fits in with their lifestyle, it can work very well,” he said. “A large part of their waking day is when things are quieting down.”