Can you walk and chew gum at the same time?

My students realize very quickly that it's difficult to look at music AND watch where you play at the same time. What is it about the hammered dulcimer that makes this so hard?

• The hammered dulcimer is not a linear instrument. The player must determine cross-over points in order to stay in a particular key. Bridge and valley crossings are not obvious on the printed page of music. They must be worked out. On top of that, sometimes when notes are moving UP the music staff (up in pitch) the player's hands must move over and DOWN, and sometimes when notes are moving DOWN the staff (down in pitch) the player's hands must move over and UP. That will mess with your mind. 
• The hammered dulcimer has duplicated notes. Choreographing a tune to the instrument is always one of the first things to do while working out hammer patterns and making a plan for play. Again, where to play a particular note is not obvious on the printed page.
• The hammered dulcimer is not regularly played with separate hands as in playing a keyboard. While "hand-separation" … i.e. one hand plays the treble clef and the other plays the bass clef ... is a technique used in playing the hammered dulcimer, it is not the standard method of play. Hands are typically integrated, working together to perform left hand/right hand combinations within the melody line and including any added harmony ideas.
• Finally, the hammered dulcimer is a visual instrument. There is no tactile connection between the player and the instrument. The player never touches the instrument. (OK, well, maybe sometimes we will pluck or bend a string for effect.) Typically, our hands hold hammers which are suspended in the air above the instrument. We're just hoping against hope that the correct string will be struck when that hammer comes down! Players train their hands, ears, and brains to recognize patterns and intervals. We develop muscle memory. We STILL must have the visual connection.

Reading for the hammered dulcimer does get easier with time and practice. Written music is a fantastic resource and memory tool. Reading music (notes and rhythms) is very helpful in learning tunes and keeping track of tunes and arrangement ideas you want to remember. But the bottom line is: In order to play the hammered dulcimer with fluidity and musicality you're going to have to memorize what you play. The sooner you get away from the sheet of music, the better.