A woman being noisy in an office (Fuse | Getty Images)

Researchers had 24 people perform a series of tests simulating the kinds of things you do at work, like information searching and generating words, in both a quiet environment and one with people speaking in the background. No surprise: Workers in the noisy room performed 8.7 percent worse on the search task, and 10.6 percent worse on the word-finding task.

It may not sound like a big difference, but consider that with a 40-hour work week, that would be like having to stay until 9:30 p.m. every Friday to finish everything. (Lagging workday? Here's How to Speed Up Time.)

While ringing phones and noisy copiers are trouble enough, the real problem is the conversations you can barely overhear. "Studies with a specific focus on speech sounds have shown that the more intelligible the background speech is, the lower the performance," says study author Helena Jahncke, Ph.D., a professor of environmental psychology at the University of Galve in Sweden. It's not clear exactly why this is, but one theory is that your brain automatically wants to devote mental resources to understanding speech, so that means less brain power devoted to your own thoughts, Jahncke explains.

Blame the recent trend of "open concept" offices, where even short cubicle walls are disappearing in favor of everyone sharing a big desk, for your inability to stay focused. "Arguments for companies to switch from cell offices to open-plan offices include facilitation of the employees' communication and creativity," Jahncke says. "There is, however, no clear scientific support for such hopes." (Don't be that guy. Avoid the 10 Ways You're Driving Your Coworkers Nuts.)

Unfortunately, you can't renovate your building's floor plan or build a private bubble at your desk to work in. So here's how to defeat the noisy distractions at your job and boost your productivity.

Pop in Earplugs
The only real solution for an employee to eliminate noise is to wear earplugs, says Jahnke. You can probably pick up a good, soft pair at the drugstore for around a dollar. Or plunk down the cash for a set of active noise-canceling earbuds, like the Klipsch Image S4 ($80, amazon.com). Prefer to block out noise with a good Pandora playlist? The research on whether listening to music increases productivity is mixed, so if it helps you, go for it--but if not, save your tunes for the ride home.

Work from Home Occasionally
In the study, the workers' performance on tests involving math and skills similar to brainstorming was unaffected by the noisy environment. That means you can save the mindless busywork for the office, but if you've got a big task that involves deep concentration coming up, see if your boss will let you tackle it from home. It might even save the company money. "The hidden costs involved with a lack of productivity, in addition to the increased risk of illness due to exhaustion, can be huge," says Jahnke. (Itching to ditch your daily commute? Here's How to Ask Your Boss to Work from Home.)

Ban Songs as Ringtones
Here's a study to bring to your boss: Research at Louisiana State University found that having songs as ringtones were the most disruptive to productivity, followed by a more standard "ringing" sound. Your move: Send out an office memo to see if everyone will agree to set their cell phones to vibrate during the day. You'll get more thanks from your coworkers than grumbles.