Minka Wiltz, an actress in Atlanta, has tried to answer her phone to the thrrrrup, thrrrrup, thrrrrup of a truck bouncing down a pothole-pocked street.

Others say they thought they heard phones ring while taking a shower, using a blow-dryer or watching commercials. What they are hearing is a barely discernable sound — perhaps chimes, a faint trill or an electronic bleat — that they mistake for the ringtone of their cellphone, which isn't ringing. This audio illusion — called phantom phone rings or, more whimsically, ringxiety or fauxcellarm — has emerged recently as an Internet discussion topic and has become a new reason for people to either bemoan the techno-saturation of modern life or question their sanity.

Some sound experts believe that because cellphones have become a fifth limb for many, people now live in a constant state of phone vigilance, and hearing sounds that seem like a telephone's ring can send an expectant brain into action.

"My experience has been hearing just a few notes that are similar to my phone's ring, my brain will fill in the rest," said David Laramie, a doctoral student at the Los Angeles campus of the California School of Professional Psychology, who is writing his dissertation about the effect of cellphones on behavior.

But Guy Moore, an assistant professor of physics at McGill University in Montreal, said human ears do not do a good job finding the source of sounds around 1,000 hertz using either method, so that a noise in that range seems just as likely to be coming from the television to the right as a purse sitting to the left.