Sensation from movements of parts of our body which are conveyed to our central nervous system are called "proprioceptive" (self-perceiving), as opposed to "exteroceptive" (tactile) sensations.
Proprioceptive sensations and the ability to make the finest inner analysis and synthesis of these sensations are necessary and the ability to make the finest inner analysis and synthesis of these sensations are necessary for acquiring motor skill. These motor signals also represent the only material through which our motor acts are built and developed. Hence, when aiming for the most efficient piano practicing, we have to take care that our proprioceptive sensations are clear and distinct. Slow playing serves this claim to some extent.
While practicing, slight exaggeration of movements will be of benefit in providing more vivid proprioceptive material, which must be as if imprinted in the corresponding cells of our brain. The contours of this imprint have to be precise and distinct. For better results these sensations should be consciously perceived.
The Art of Piano Playing. A Scientific Approach (página 24)