We’ve all been there — sitting in a public place, and feeling like that person over there, talking on their cell phone, is so annoying. Why are they so annoying? What makes a cell phone conversation that you overhear so distracting?
Four researchers, led by Lauren Emberson (2010) from Cornell University, set to find out.
Previous research has shown that we don’t seem to be as distracted when listening to a full dialogue between two people as when we are listening to a “halfalogue” — that is, just one side of a two-sided conversation.
In two small studies conducted exclusively on 41 college undergraduates, the researchers devised tasks to measure how distracting mobile phone conversations are when we hear only one side of the conversation. Specifically, they were interested in measuring whether such conversations could affect our ability to concentrate on a task that demanded good attention in order to complete successfully.
In the first study, 24 undergrads were seated in front of a computer and told they were going to complete two tasks that demanded their complete and undivided attention:
One involved tracking a moving dot with the computer mouse, and the other involved responding to letters presented on the computer screen. They were given 1 min of practice with each of these tasks in silence. They were then instructed that they would be completing these tasks a number of times and would sometimes hear speech from the two computer speakers situated on either side of the monitor. Participants were asked to focus their attention on the attentionally demanding tasks.
They found significant differences in a person’s ability to concentrate on both tasks at hand when listening to half a conversation (the “halfalogue”) as opposed to silence, a monologue, or a complete two-sided conversation.
Since the researchers reasoned this effect may be caused by the unpredictability of simply the sounds of talking themselves, they conducted a second experiment that made the halfalogue conversation filtered and incomprehensible. They found that it isn’t the mere acoustic unpredictability itself — speech comprehension is necessary in order to reduce a person’s attention to the task at hand.
The researchers suggest that the reason that half a conversation is so distracting — and therefore, most cell phone conversations we overhear — is because the speech processing part of our brains is drawn to make sense of the pattern we’re hearing. Since it generally can’t do this with only half the data, our brains are straining under the load of this processing task. In a normal conversation, speech is predictable — Person A talks, then Person B responds, and so on.
In half a conversation, you don’t know what Person B is saying, so you also don’t know when or how Person A will respond. This is curious to the speech processing centers of our brains, apparently, and causes us to become distracted in trying to make sense of the conversation.
Finally, the researchers note why this finding may have more generalizable importance. We know from previous research that cell phone conversations by a driver in an automobile can negatively impact driving performance. In fact, some states have gone so far as to enact laws banning cell phone use while driving.
But this study demonstrates something even more disturbing that few lawmakers have considered — simply overhearing a cell phone conversation in the car (e.g., from one of your passengers) may also be significantly distracting. It may be sufficient to reduce a driver’s reaction time and performance, although further study would be needed to verify this hypothesis.
So now you know why cell phone conversations can be so distracting — it’s your brain’s attempt to make sense of the conversation without sufficient data (e.g., the other side of the conversation) it’s used to having. And it’s not just mobile phone conversations — it’s really any conversation conducted where you can only hear one side of it.
Emberson LL, Lupyan G, Goldstein MH, & Spivey MJ (2010). Overheard Cell-Phone Conversations: When Less Speech Is More Distracting. Psychological science : a journal of the American Psychological Society / APS PMID: 20817912