Some who have experienced this recurring phantom vibrations have wondered whether the strange phenomenon has physical roots: Is it caused by nerve damage or muscle memory? The answer is quite intriguing:

Some call it "phantom vibration syndrome." Others prefer "vibranxiety" - the feeling when you answer your vibrating cellphone, only to find it never vibrated at all. "It started happening about three years ago, when I first got a cellphone," says Canadian Steven Garrity, 28, of Charlottetown, Prince Edward Island. "I'd be sitting on the couch and feel my phone start to vibrate, so I'd reach down and pull it out of my pocket. But the only thing ringing was my thigh." Though no known studies have analyzed what may cause spontaneous buzzing, anecdotes such as Garrity's ring true with the public. Spurred by curiosity, Garrity, a Web developer, described the recurring false alarms on his blog. The response was not imaginary: More than 30 cellphone users reported that they, too, experienced phantom vibrations.

Psychologically, the key to deciphering phantom vibrations is "hypothesis-guided search," a theory that describes the selective monitoring of physical sensations, says Jeffrey Janata, director of the behavioral medicine program at University Hospitals in Cleveland. It suggests that when cellphone users are alert to vibrations, they are likely to experience sporadic false alarms, he says. "You come armed with this template that leads you to be attentive to sensations that represent a cellphone vibrating," Janata says. "And it leads you to over-incorporate non-vibratory sensations and attribute them to the idea that you're receiving a phone call."

Phantom cellphone vibrations also can be explained by neuroplasticity - the brain's ability to form new connections in response to changes in the environment. When cellphone users regularly experience sensations, such as vibrating, their brains become wired to those sensations, Janata says.