aAnother DOF problem is the misuse of integral and separable DOFs. Jacob & Sibert (1992) showed that input devices with integral DOFs (those that are controlled all together, as in a 6-DOF tracker) should be mapped to tasks that users perceive as integral (such as 6-DOF object manipulation), while input devices with separable DOFs (those that can be controlled independently, such as a set of sliders) should be mapped to tasks that have sub-tasks users perceive as separable (such as setting the hue, saturation, and value of a color). A violation of this concept, for example, would be to use a six-DOF tracker to simultaneously control the 3D position of an object and the volume of an audio clip, since those tasks cannot be integrated by the user.