Whenever a concept is first introduced, it is important to ground it in a concrete perceptual-motor experience. The learner will ideally visualize a picture of the concept, will be able to manipulate its parts and aspects, and will observe how it functions over time. The teacher and learner will also gain a common ground (shared knowledge) of the learning material. Perceptual-motor experience is particularly important when there is a need for precision, such as getting directions to find a spatial location. For example, a course in statistics is not grounded in perceptual-motor experience when the teacher presents symbols and formulae that have no meaning to the student and cannot be visualized.