Have you ever had a particularly musical friend talk about "perfect pitch"? Perhaps he just mentioned it and you have no idea what it is; perhaps you were explained what it is, but you're still confused. And to be honest, I myself have never heard anyone give a really solid explanation of it. But let me give it a shot.

Perfect pitch is the rare ability to be able to identify a note, chord, or key by just hearing it; it can also be the ability to reproduce a note without hearing it at all, or pulling it out of thin air. So, if I had perfect pitch, I could hear someone play a D on the piano, and without looking, I'd be able to say, "that there's a D". Likewise, if someone asked me to sing a D without letting me hear it first, I'd be able to. Pretty neat, huh? Interestingly (and quite surprisingly to me), this ability only occurs in one out of every ten thousand people.

Don't believe everything you, hear, though: alot of musicians like to claim they have perfect pitch when they really don't. That's because of a thingamabob called relative pitch, which is quite common. When a musician has relative pitch, it just means that he can hear a note and then sing a different note. You probably have relative pitch. If someone were to play the first "twinkle" in "Twinkle Twinkle Little Star", you could most likely sing the next "twinkle" with complete accuracy. That's easy stuff.

The thing about perfect pitch that is so elusive is that there's not one way to define it; there are quite a few. A musician might be able to identify a note but not a chord, which is a combination of notes. Or he may be able to tell you what key a song is in, but not the notes being played. Or he might only be able to identify notes and chords and things on certain instruments, since all instruments sound unique. Or he might be able to sing the note without hearing it, but not be able to identify it when hearing it, or vice versa. Or he might be able to do all of these things. How confusing, eh?

So how does perfect pitch work, anyway? Well, it's not a mystical ability granted at birth by the spirits of Bach and Beethoven. It's just some good long-term memory skills. When a perfect-pitch musician hears a note, his mind begins to work, and he goes back to the last time he was able to identify the note (probably when seeing it played on an instrument) and he is then able to identify it again. So, hypothetically, if I hear a D being played, I think back to the last time I made that sound on the piano or banjo or guitar, and I remember that when I made that sound, I knew it was a D, so I'm then able to identify the note being thrown at me now as a D. The musician essentially remembers a visual reference (usually the instrument), which means that perfect pitch is a sort of synesthesia. The brain uses a visual reference to differentiate between frequencies, just like it uses visual references to differentiate between hues in order for us to identify colours.

Now, you might ask, "Doesn't that mean that I could have perfect pitch, if it's all a memory game?" And the answer is yes. I would argue that not only is perfect pitch trainable, but that training is the only way to achieve perfect pitch. Of course, in order to train yourself to have perfect pitch would require insane amounts of ear training and music lessons, with the majority of your day spent listening to the same few songs over and over until you could identify the notes and chords and keys, and you'd probably have to become a multi-instrumentalist with a repertoire as long as War and Peace. Fortunately for perfect-pitch musicians, they've already done all this, in their childhood, while they had the time. If you're old enough to grasp the concepts of this article and you're not musical at all... you'd have quite the task ahead of you.

So, there you have it, the short and simple version of how perfect pitch works that wasn't very short or simple at all. If you want to test yourself or somebody else for perfect pitch, just tap a note on the piano without letting them look at it, or have them play a note without you looking. Can you guess the note correctly?