Human infants are sensitive from birth to some intrinsic properties of objects; they are also sensitive to position. During the first weeks of life, pertinent dimensions of differentiation between objects are relative to global properties of the entire object or pattern. Position is defined by the direction of a displacement: the trajectory followed by a mobile object, the orientation of the infant's body, or the direction of a movement like head turning or arm thrusting. Movements are differentiated by their direction relative to the infant. During this early period, regularities can be observed between changes in the environment and modifications in the infant's behavior. However, differentiation and recognition measured by a specific index (fixation time, for example) are relative to changes or non-changes in global sensorimotor exchanges between the infant and his or her environment. It is only when these sensorimotor exchanges become dissociated in their components that the infant will progressively become able to identify and differentiate perceiving and acting, position and intrinsic properties, etc. As a component is isolated and functions independently from others, it can enter in relation with others to form structured sensorimotor or intermodal coordinations. This conclusion is not original; other researchers work according to the same assumptions within their own theoretical frames. (Author/RH)