The researchers observed how it has become the modern equivalent of glancing at your watch -- the furtive look at a phone screen to check for new messages or have a quick look at Facebook, Daily Mail reported.
People are twice as likely to pull out their phones to check their text messages or e-mail if they're with someone who has just done the same, a University of Michigan team found.
It also found how women were more likely to use their mobile than men since it was more "integrated into the daily lives of women".
The team watched students in dining halls and coffee shops around campus between January and April 2011, observing pairs of students sitting at tables for as long as 20 minutes and documented their cellphone use at 10-second intervals.
"What we found most interesting was just how often people were using their mobile phones," Daniel Kruger, the study's co-author, said.
"Every person we observed used his/her phone at least once while one woman was on hers about half of the time.
"Individuals may see others checking their incoming messages and be prompted to check their own."
It was found overall, the students used their cellphones on an average of 24 percent of the intervals.
But they were significantly more likely to use their phones (39.5 percent) when their companion had just done so in the previous 10-second interval, the researchers said.