Listening to one-side of a cell phone conversation as some thoughtless person yaks on is really annoying. That's no news. But a just-published study out of the University of San Diego shows that when you're subjected to other people\u2019s conversation on their cell phones you'll be much more distracted than you thought, and much more distracted than if you had listened to a conversation by two people in the same room or elevator or train.\n\tThe researchers found that those one-side conversations lower the ability to concentrate and make the unwilling participants quite irritated. It also appears one-sided conversations stick in the brains of unwilling listeners. The test subjects in the study remembered more of the one-side conversations than they did when listening to two-sided conversations.\n\tThe subjects were college students who were asked to complete anagrams while a nearby researcher talked on a cell phone. They didn\u2019t know that the conversations were actually part of the experiment; they thought the study was examining the relationship between anagrams and reading comprehension. The few students who figured out what was really going on, were dropped from the study.\n\tAlthough it's obvious that listening to a stranger\u2019s conversation is annoying, the answer to why a one-sided conversation is so distracting is much less intuitive. \u00a0After all, the world is full of other people talking to each other, so what\u2019s the difference?\n\tResearchers say that we tend to focus on new or unexpected things or events. "When you\u2019re listening to one half of a conversation, every new utterance is a surprise, so you're forced to constantly predict what\u2019s going to happen next," Lauren Emberson, a researcher at the University of Rochester, told the New York Times. \n\tWith cell phone use an ever-present fact, scientists are studying it more frequently, and finding evidence of its annoying and sometimes dangerous effects.\n\tYou've probably noticed how loud people speak on their cell phones. But you might be wrong. In a 2004 study, 64 commuters were exposed to the same conversation at different volume levels, half as a cellphone call and half as a face-to-face talk. On average, the commuters thought the mobile phone talkers were louder, even when they were not.\n\tOther research has shown that your chances of being in an accident when driving while talking on a cell phone, even if you\u2019re in the hands-free mode, are as high as if you had been drinking, according to data cited in the University of San Diego study.\n\tPedestrians talking on cell phones while crossing the street are courting danger as well. One study found that cell phone talkers were so distracted that they didn't even see a clown riding on a unicycle as they crossed. Now that's distracted.\n\tThere's another issues that studies don't speak to, and that's politeness. It's simply rude to interrupt someone else's quiet commute, or lunch, or even their time trapped in a line to buy a ticket, with your conversation.\n\tI realize, of course, that digital devices are redefining etiquette, but when did simple courtesy go out of style?