Consider that a conversation by telephone—when you are simply sitting by and not taking any part in that conversation—is one of the solemnest curiosities of this modern life. Yesterday I was writing a deep article on a sublime philosophical subject while such a conversation was going on in the room…. You hear questions asked; you don’t hear the answer. You hear invitations given; you hear no thanks in return. You have listening pauses of dead silence, followed by apparently irrelevant and unjustifiable exclamations of glad surprise or sorrow or dismay. You can’t make head or tail of the talk, because you never hear anything that the person at the other end of the wire says.

As Twain put it, you “can’t make head or tail of the talk,” and Emberson thinks this is the root of why cell phone conversations so effectively capture our attention—and subsequently annoy us. When you hear only half of a conversation, it’s hard to predict when the person will start talking again and what that person is going to say when he does open his mouth.

Part of the recipe for what makes something annoying seems to be its level of unpredictability. Completely random stimuli, we can tune out. We also have an easier time ignoring something that is steady, stable, and routine. But things that have some pattern, like the rhythm of a conversation, but are not predictable—grab our attention, whether we want them to or not.

Speech, especially, reels us in. You might think that when you’re having a conversation with someone your brain is focused on listening, on taking in what that person is saying and processing the information he’s imparting. You probably think you’re absorbing his words like a sponge and possibly preparing your response. In fact, your brain is focused on guessing what the person is going to say next. You may be able to finish your spouse’s sentences, but your mind wants to finish everyone’s sentences.

Humans are always trying to predict speech, says Liberman. It relates to an idea called “theory of mind,” which suggests that people can’t help themselves from trying to read into what other people are thinking. “It’s also pretty much automatic,” he wrote on his blog Language Log.