This is something that I've been thinking about a lot lately. Recently, I was quoted on a blog that appeared on the Novation website, where I was asked about the Launchpad pro as a practical instrument to replace the traditional piano keyboard. I tend to use both for different reasons, and I felt it was important to point out something that was stated by Don Buchla some years ago about the nature of tactile interface in the human brain…
Loosely paraphrased, he pointed out that human beings have difficulty recognizing clusters of more than four or five objects at a time. This is especially difficult if said objects appear identical. as a result, the traditional piano keyboard is something that the brain encompasses more easily than one might expect… It consists of groups of black keys with white keys around them that are easily broken down by the brain into manageable chunks.
The contrasting shapes, sizes, and positions of the two types of keys provide anchor points for muscle memory, making it easier to memorize hand positions in multiple keys than one might expect. While isomorphism has its benefits, this lack of distinction between neighboring keys actually contributes to a mental equivalent of throwing up one's hands and giving up!
This is frequently seen in the frustration that people have with generic control surfaces. Long rows of effectively identical controls can lead to confusion and frustration. The more generic and uniform the interface, the easier it may be to map, but the more difficult it is for the brain to follow and turn into effective action.
This is one of the reasons why I favor synthesizers as Control surfaces. They have controls that are grouped into small and logical blocks that are easy for the brain and hands to work with.
my recent design efforts on multitouch surfaces reflect this. I try to avoid having large rows of identical controls, because they're simply confusing. This is especially important because tactile contrast on such a surface is nonexistent.
Please forgive the bump of this very old topic, but this is something I feel strongly about, and the existing discussion has been fascinating.