Over the years, there have been a number of variations in keyboard design, be it folding ones, washable ones, ones that also function as a mouse, and thumb-sized keyboards, just to name a few.
One particular thing in common is that there are bumps on two keys on all of these keyboards. But why?
To find out the reason behind this, place the index finger of your left hand on letter F and the index finger of your right hand on letter J, and then place the other fingers of your left hand over the letters A, S, D and the fingers of the right hand over the letters J, K, L and the semi-colon. You will realize that it is the best placement of hands on the keyboard.
These bumps are there to help you correctly place your hands on the keyboard and to identify the keys without having to look down at at it time and again.
Professionals make use of these bumps to get a feel of where the hands are. Muscle memory remembers this placement when an individual spends time moving the hands around in this way. Once the muscle memory takes over, a user can type without looking at the keyboard.