Next time something you hear goes in one ear and out the other, you have a built-in excuse. Just blame it on your Achilles' ear—a weakness that lies not in a mythical hero's heel, but in the real-life way the brain processes sound and memory.

That's the suggestion of a University of Iowa study comparing how well we recall something, depending on whether we see it, hear it, or touch it.

Associate professor of psychology and neuroscience Amy Poremba and graduate student James Bigelow asked a hundred undergraduates to participate in two related experiments. In the first, students listened to sounds, looked at images, and held objects. Then, after an interval ranging from one to 32 seconds, they were asked whether