Overheard cell phone calls are unavoidable, as much as you might like to tune them out. A new study confirms what you already knew - that overheard phone conversations are much more distracting than normal background chatter.
Because you can only hear one side of an overheard cell phone conversation, your attention is more easily drawn towards understanding it than it would be to a two-sided conversation - even, or especially, if you're trying to pay attention to something else.
The study was published in the journal PLOS One on March 13, by Veronica Galván and colleagues from the University of San Diego.
The researchers asked participants to complete a cognitive task that had them solve anagrams. As they performed the tasks, actors in the background staged a conversation in the background about shopping for furniture, planning a birthday party, or meeting a date at the mall.
Half of the participants only overheard one side of a cell phone conversation, and the rest overheard a conversation between two people in the same room. None of the participants were told that the real purpose of the study was to see how easily distracted they were from their tasks.
"This is the first study to use a realistic situation to show that overhearing a cell phone conversation is a uniquely intrusive and memorable event," said Galván in a statement.
"We were interested in studying this topic since cell phone conversations are so pervasive and could impact bystanders to those conversations at work and in other settings of everyday life."
The participants who overheard the cell phone conversation found it much more distracting than those in the other group. They also remembered more of the content of the cell phone call, and more easily recognized which words were part of the phone call.
The researchers suggest that this effect can be explained by the extra attention resources a person needs to understand a one-sided conversation.
Hearing both sides of a conversation makes it easier to understand, and thus less distracting. When you only hear one side of an overheard phone conversation, you're more likely to devote brainpower to imagining the other side- even if you would rather not.
"Not knowing where the conversation is heading is what makes cell phone calls more distracting", said Rosa Vessal, a co-author on the study.
Galván also suggests that since people tend to reveal personal information on cell phone calls, even in a public setting, it's especially difficult to ignore and more tempting to eavesdrop.
This is all fairly obvious, but Galván believes that it could have implications for workplace productivity. If people are carrying on cell phone conversations while at work, other employees could be distracted to the point where they are not getting their work done.
"A person's performance might be greater in an environment with fewer one-sided conversations," Galván told Forbes. "In some situations, this is not feasible...or impractical to implement, because some work places are inherently noisy."
If you're on a long, crowded bus or train ride, however, resign yourself to eavesdropping on those conversations-- you're not likely to concentrate on much else without noise-canceling headphones.