CORNELL (US)—Overhearing people chatting on mobile phones can be more than annoying. It’s so distracting that it affects cognitive performance, new research shows.

Overhearing only half of a conversation—a halfalogue”—is more distracting than other kinds of conversations because the listener misses the other side of the story and so can’t predict the flow of the conversation.

Drivers may be significantly compromised by overhearing the cell phone conversations of their passengers, says Michael Goldstein, assistant professor of psychology at Cornell University, and doctoral candidate Lauren Emberson, who is also affiliated with Weill Cornell Medical College’s Sackler Institute for Developmental Psychobiology.

“Hearing half a conversation is distracting because we are unable to predict the succession of speech. It requires more attention,” says Emberson, first author of a paper on the research that will appear in an upcoming issue of Psychological Science.

“We believe this finding helps reveal how we understand language in conversation: We actively predict what the person is going to say next, and this reduces the difficulty of language comprehension.”

Experiments show that people overhearing cell phone conversations did more poorly on cognitive tasks that demanded the kinds of attention we use to tend to daily activities, than when overhearing both sides of a cell phone conversation or a dialogue, which resulted in no decreased performance.

“Since halfalogues really are more distracting, and you can’t tune them out, people become irritated [and], even more importantly, their cognitive performance is impaired,” Goldstein adds.

While others studies have shown that talking on a cell phone can impair driving performance in contrast to listening to the radio or talking with a passenger, this study takes it a step further.

“Our findings demonstrate that simply overhearing a cell phone conversation is sufficient to reduce performance … [suggesting] that a driver’s attention can be impaired by a passenger’s cell phone conversation,” the researchers write.

With more than 285 million wireless subscribers in the United States alone—and about 4.6 billion cell phone subscribers worldwide, according to the International Telecommunications Union, a U.N. agency—cell phone distraction is becoming increasingly ubiquitous in public places, from coast to coast, the researchers note.

Researchers from the University of Pennsylvania and the University of California-Merced contributed to the study.

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