Before I was moved to an act of airport-terminal , 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.

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 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...

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