Sometimes when I’m thinking having trouble deciding what to write about for my next blog entry, fate steps in. I was sitting at the airport getting ready to fly to Dulles airport trying to get some reading done. Unfortunately, I was having a hard time concentrating. There was a guy standing behind me with a Bluetooth receiver in his ear jabbering away to someone in his office. Every time I managed to start reading again, my attention would be wrested from the page to hear half of his conversation.
Before I was moved to an act of airport-terminal-rage, I was saved by the boarding announcement. I got on the plane and pulled out the October, 2010 issue of Psychological Science. In it was an article by Lauren Emberson, Gary Lupyan, Michael Goldstein, and Michael Spivey that demonstrated exactly what was going on for me.
The authors pointed out that there are two problems with overhearing cell phone conversations. First, you only hear half the conversation. When there are two people sitting behind you talking (that is having a dialogue), you get both sides of the conversation, and so you can follow what is happening. If one person recites a monologue, the text is coherent (though I’d be a bit concerned about someone monologuing in an airport). Cell phone conversations, though, give you only half of the conversation. You can’t hear what the person on the other end is saying, and so the speech you do hear is not that coherent. The authors call this a halfalogue.
Second, the overheard conversation seems to start and stop at random. It is hard to predict when the speaker is going to start and stop, because you can’t hear the other side of the conversation.
The authors of this study demonstrate that hearing a halfalogue is particularly draining of your attention resources. They had people do two difficult tasks. In one, they had to track a randomly moving dot on a computer screen with the mouse cursor. In another, they had to remember a set of letters, and press a button whenever one of those letters appeared on a computer screen. While they did this task, people heard either a conversation between two friends, half of that conversation (as if they were hearing a cell phone conversation) or they heard a monologue that summarized a conversation between friends. The dialogue and the monologue did not affect people’s performance on these difficult tasks much. But, the halfalogue was devastating. People’s performance got much worse when hearing just half the conversation.
Then, the authors did a clever manipulation to demonstrate why this happens. They took the dialogue and the halfalogue and filtered the signal so that it sounded vaguely speech-like but was not understandable. They had another group of participants do the same tracking and memory tasks listening to this filtered speech. Neither the filtered dialogue nor the filtered halfalogue affected people’s performance on the difficult tasks. That suggests that the problem with cell phone conversations isn’t that the sound starts and stops at seemingly random points. Instead, it indicates that when you hear a cell phone conversation, you can’t help but try to pay attention to what the conversation means. Because you’re only getting half the conversation, though, you can’t really understand it, and that drains attention.
On the positive side, now I know why it is so annoying to hear cell phone conversations in public places. On the negative side, it doesn’t appear that there is much I can do about it. Maybe Brookstone sells some kind of Bluetooth jamming device…