“Mental ability is likewise developed through repetition. An inexperienced cook will have a different perception of a “uniform” slice than the experienced cook. The inexperienced cook is still learning the macroscopic elements of cutting an onion–things such as hand positioning and maintaining a well-honed knife–and has less focus on finer details. In the case of a uniformly sliced onion, the beginner cook might not notice variance of up to a finger’s breadth, but as she continually practices her knife-work and the basic technique becomes natural, she will see inconsistency in terms of millimeters