When she needs to focus, Katie Kennedy, 23, wears an earbud to listen to the Dave Matthews Band and John Legend at her job at Version 2.0 Communications. She usually just wears one, she said, so she can hear what’s going on with her other ear.

But her boss, Maura FitzGerald, who has a three-quarter-walled office beside Kennedy, finds that’s not always the case.

“I can’t just think of something and call her name out,’’ said Fitzgerald, 60, a partner in the public relations firm. “I did it for a while and wondered, why isn’t she answering me? Has she forgotten that I’m the boss?’’

Most of the employees in the 15-person office wear headphones. Fitzgerald said she has no policy against the practice because it keeps employees happy and work gets done. But it does not mean she likes it.

“We have a collaborative team-oriented environment, and I do feel from my perspective that when I see someone wearing headphones, they’re kind of under the cone of silence,’’ she said.

Dimitry Herman is not a big fan of headphones, either. About three-quarters of his 60 coworkers at the Boston software company FreeCause wear headphones - and he worries it could spread.

“Before you know it,’’ said Herman, 40, a director of business development at the firm, “everybody’s tuned in to their own world and not interacting in the way that was originally intended by the open floor plan.’’

Studies on the effect of music and background noise on productivity have yielded conflicting results. A British study in 2010 found that listening to music impaired people’s ability to recall information, while the famous “Mozart Effect’’ studies in the early 1990s showed that listening to Mozart improved people’s ability to find solutions to complex problems.