There is a sweet spot on each fret right behind the fret. If you get too far behind the fret, or right on top of it, you get a less clear sound, distortion, buzz, etc. I think playing very slowly and cleanly especially when practicing up tempo songs yields the best results. I do think that muscle memory is important. Whether you are playing chord shapes or with a noter, your body gets used to playing on the sweet spots if you practice right. That's why it takes a bit of getting used to when I change dulcimers with a different VSL. So I think watching the fret board is very important until you get to a point where you are able to play cleanly without watching... sort of wean yourself off of it. Obviously if you are learning a song from tab or sheet music, you aren't as concerned with performance, but after its been memorized, unless your playing is somewhat advanced, I recommend watching what you are doing so that you don't practice something you don't want to be playing. But this is just how I play... everyone is different of course. When using the dulcimer to accompany a vocal, it's nice to not have the head looking down all the time, especially if performing.
I do on all the fretted instrument that I play.....I'm am perfectionist .....and control freak .....
It's right in front of you - why would you not look at it? Many other instruments of course you play reading from sheet music, so you can't look at your instrument. I've come across people who can't play their violins unless there's a music stand in front of them with the music on, but when you watch them most of the time they're not looking at it and even have their eyes closed - but take the music away and they can't play!
Also the dulcimer is mostly played to oneself while pianos etc are often being `performed' for others. Does it really matter, just do what you're comfortable doing.
Dean - I think thatif you switch your question around you will have the answer. Ask yourself: "What makesfolks NOT look at the fretboard? "Traditionally the instrument would have been played by ear, mostly for personal or family entertainment (ie not withmusic or TAB orfor an audience or withother band members or a conductor). Quite simply, there was no reason NOT to look down at the instrument. Those of us who play mostly by ear at home are likely to look down at the fretboard more than those who use TAB or music or who play with other musicians orplay gigs. Not looking down is a learned skillso there has to be some intrinsic motivation to cause that learning to take place.
I have noticed in myself that I look down at the fretboard when I play most of the time and that my playing is based on visual pattern movement. However, when learning a new piece from music I follow the music and play by feel (missing the odd fret and looking at the big jumps) - because the skill of not looking is useful when reading music. When I play in a string band (quite regularly), I will perhaps look down when soloing but look up and around at the other players when playing backing - because the skill of not looking down is really useful when playing with others. So it is the demands of thecontex the will drive whether or not a player hasneeded to learnto play head up or head down - and I think that has come across in all the previous replies to your question. If you play by music or TAB you will need to not look at the fretboard. If you play with others you will need to, at times, not look at the fretboard. If you play by ear primarily for yourself then learning the skill of not looking is not important.
Right from the very earliest days of mountain dulcimer playing you will see this reflected in photos:
Ed Thomas strumming away on a porch somewhere, lost in his music and......looking down 
He had no reason to learn to do otherwise 
Dean Patrick Preising said:
.....I still find it interesting when I look at pictures, most people are staring intently down at the fret board, while people playing other instruments are not.
Dean
And she drove the car? Over here (Holland) it is enough using your cell phone for the police tostop you...
I know exactly why I myself sort of have to look at the fretboard when i play dulcimer ... when I play banjo, not only are my fingertips pressing on the fretboard, but my left hand or at least my thumb, is curled around the neck and thus giving me a physical reference point , a sense of where 'home' is for frets 1-5. Much the same as when folks plant a pinky when flatpicking across strings on mando, guitar, bluegrass banjo, and dulcimer too. Without that pinky plant, it's much harder to pick individual strings accurately when not looking- the pinky tip is the reference point. even with clawhammer banjo, most folks at least have their thumb on the back of the neck and it works well as a reference point. I can play banjo pretty well without fretboard looking, but not dulcimer.
With a mtn dulcimer, we don't have our left hand wrapping or curling around the neck for a reference point, once you go up and down the neck either fingering notes or using a noter, it's hard to know where the frets exactly are anymore. Of course this is a skill that can be developed and improved (look at highly skilled hammered dulcimer players), but most folks use the eyes becasue the physical reference point is not there as it is with necked instruments.
I know I have a terrible time when we play at night while camping, if we are playing by low lantern light and my fretboard is not getting any light at all. 
A good exercise is to try playingh for varying time lengths with your eyes closed....quite an education!
All that said, I'll look at my fretboard if I please to! :)
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Site Owner
Those irritated by grain of sand best avoid beach.
-Strumelia proverb c.1990
Look as much as you need to look. But not one glance more.
I still believe that too much is made of "not looking at the fret board". In a performance, what's wrong with looking at the work you are doing? Sure, you have to take your eyes off of the fret board a lot of the time, eye contact with the audience is important. Great guitarists like Jimi Hendrix, Neil Young, Bob Dylan & Keith Richards all spent time during performances looking at their fingers to get the music as perfect as can be. Young even closes his eyes on some songs for sometimes a minute at a time. If your heart is into the song, and you have confidence in your skill for this one song by preparing yourself mentally and physically, then there is no need to be worrying about staring at the fret board too long and making eye contact with the audience. It just happens. Just be your natural prepared self.
Riding a bike hands-free has to do with the gyroscopic effect of a running wheel and the bending of the fork of the front wheel combined with the center of gravity:a bottom in the saddle. That's plain physics and not being afraid... Hands-free standing in front of a traffic light with both feet on the pedals (sur place) or riding uphill standing on the pedals is almost impossible!
No need to look at the fret board is a psycho-motoric matter, createdin our brain and spine.
So, the challenge: riding a bike solo while playing the dulcimer on your lap! And watching the traffic at the same time :D
I think muscle memory isnt that important due to the diatonic fret board, special in the lower octave. There is enough space to get the right tone. The same goes to the VSL, I think. More troublesome is the retuning of the strings, which enables to play the tune right, also due to the diatonic structure.Sometimes a song needs the 5/6/6+/7 frets and a capo. Better look at the frets then
Wout
If you look at the fret board, how can you concentrate on the pretty girl in the third row?
As my old Drill Sgt. used to say,
"Ain't no use in lookin' down
Ain't no discharge on the ground."
Don't let all of us who didn't pay attention to the teacher change what you are doing. Music teachers will tell you to look at the music, not at the fret board. But try to make some eye contact with that girl.....especially if she's your wife!
Paul
Dean, let me reiterate a few points already made and add a couple of my own.
First, almost everyone will have to look at the fretboard when they first start playing. Eventually, you gain the muscle memory of where the frets are and you don't have to look as much.
Second, many of us play different instruments with different VSLs, so we can't rely on that muscle memore as much as those who play a single instrument all the time. I have five dulcimers I play regularly, only two of which are standard-sized dulcimers. The others are made to fill different tonal ranges, and their sizes vary. All five of those dulcimers have different VSLs.
Third, some songs are more complicated than others. For simple tunes played around the nut, I can play without looking at the fretboard. But other songsinvolve chords higher up the freboard and/ora lot of movement from lower frets to very high frets. It is very difficult to play those kinds of tunes without looking at the fretboard. When I play guitar, I can generally play chordal accompaniment even with bass runs and little licks without looking at what I'm doing. But if I have to take a solo, then my eyes will be glued to the fingerboard since my fingers will be moving around a lot.
Fourth, some of us don't use tab or sheet music. This might sound odd, but I learn the songs I learn. What I mean is that I use tab or music when I first learn a song, and perhpas I have to refer to that to refresh my memory of a song I haven't played ina while, but while I play I don't look at music. I find I can play faster and more precisely by concentrating solely on the fretboard and my finger placement. I don't want the distraction of looking at a piece of paper and then having to translate that paper to action on the fretboard. My fingers fretting and picking strings is all I want to think about.
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Dusty T., Northern California
Site Moderator
As a musician, you have to keep one foot back in the past and one foot forward into the future.
-- Dizzy Gillespie
What you do is your business I think many people still look at the fretboard because even though they may have been playing for years, that amounts to very few hours overall when they belong to a club that meets once a month for a copuple hours, and they don't practice in between.
The one good thing I have to say about playing from paper is that it does, at least part of the time, force the player to look at something other than the fretboard. Then you'll see the flicking eyes, like someone watching a tennis match, as they look at the page...then the fretboard...then the page...and repeat They play with their eyes rather than their ears.
Dean, I tend not to watch the fretboard as well. Since I play and sing at the same time, I usually concentrate on reading my tab for the words to the song.
I'll have an idea as to why many players would watch the fret board though. They might have more than one instrument and have varying VSL lengths. All my instruments but 2 have the same VSL lengths, which is why I tend not to play the 2 that don't. Their fret placement confuses my muscle memory. Even though one of them is only just over an inch longer as soon as I start playing it, I flub up and have to watch my finger placement. I'm a melody/drone player and so am only using one finger at a time the small difference in the VSL causes havoc with my playing.
