Natural mapping: the position of control elements in relation to the screen The functional assignment of interaction elements ­ both physical and vir tual ­ should be logically geared towards the expectations of the user. Where elements are arranged horizontally, the reading direction from left to right should be taken into account. This means that functions such as `confirm' and `next' should be on the right of the screen, and functions such as `back' and `change' should be on the left. Additional functions or options such as `fur ther information' should remain neutral in relation to their direction and placement. The ver tical axis is semantically linked with the concept that `up' equals more and `down' equals less. This can be applied, for example, to functions such as volume and zoom control. When designing soft keys, which have dynamically applied functions, care must be taken to ensure that the assignment of the physical keys is consistent, for example the `cancel' functionality will always be assigned to the same physical key. The link between the key and the screen should also be as consistent, close and unambiguous as possible. no yes lock menu back select quit options