At first sight it seems a fairly simple matter to say what is meant by being right-handed or left-handed, but a little consideration soon shows that this very simplicity is a source of difficulty. We say that a person is right-handed if he for preference uses his right hand rather than his left to carry out the more skilled kinds of movement and is more skillful at such movements with his right hand than with his left. The converse is true of a left-handed person. Handedness, therefore, is nothing absolute; it is a question of degree, a preference based upon a skill with which the two hands are used. Moreover, it takes no account of the actual degree of skill present, nor does it imply any cause for the difference.