I am left handed. I took up violin and violin lessons for a few years in my mid-forties. Here is something I figured out about handedness:
When you hammer a nail, you swing the hammer with your dominant hand (right) and hold the nail in the non-dominant hand (left). When you write, or embroider, you hold the paper or cloth in the hoop, with your non-dominant hand, and do the action (writing, wielding the needle) with your dominant hand.
With violin, the left hand "holds" the violin and that is the still hand, other than fingers popping down on the strings. The violin is acted on with the bow, and the large movements, and the movements giving all the subtly of expression, are done with the right hand. The difficulty and challenges are in the bow, not the mere notes, and the dominant right hand has been given that task.
Therefore for a lefty that setup is entirely backward. I figured at some point that for a left handed person, more time should be spent in the beginning with the bow hand, since it was handicapped by not being the dominant hand accustomed to be the one doing the action.
Regarding those studies: If someone has been learning to play an instrument from a young age (for violin it is often age 4), then a lot would have been "wired into" the nervous system. These are scientists asking survey questions of trained musicians. I'm thinking that a teacher who observes many students first hand might be best equipped.
