When you see someone walking down the street yammering to himself, with no Bluetooth in sight, he's not necessarily out of his mind. He might just be trying to bring something to mind -- and saying it out loud helps, found a study by researchers from the University of Wisconsin-Madison and the University of Pennsylvania.

Noting that people often say the names of products they're looking for while scanning grocery shelves, psychology professors Gary Lupyan and Daniel Swingley conducted two tests. In one, subjects were shown 20 pictures, then given written instructions to find one of them, like a teapot. If they looked for it silently, it took longer than if they did so while uttering "teapot, teapot, teapot" as they searched. In another shelf-scanning experiment, subjects were asked to quickly find all examples of a certain item, like bags of apples. If they repeated "apples" aloud, they were again able to complete the task more quickly.

But if the relationship between the term and what it stands for was more complex or less familiar, it slowed things down more. Women did better than men at this one, with the exception of one product, deodorant.

Dr. Michael O'Sullivan, a psychiatrist with the University of Minnesota, said the study makes sense: "The brain is like the Internet, it's a nodal system. The more areas you harness -- speech centers on top of visual centers -- the more powerful it's going to be."

So, people who talk to themselves -- on a limited basis, at least -- might be improving their cognitive functions. Now if only they'd prove the opposite about people who yell at the TV.