The development of sensory systems such as the visual system depends on both experience-dependent and experience-independent factors. The development of motion selectivity in visual cortex in ferret depends on visual experience, but are the parameters of the selectivity that emerges dependent on the details of an individual animal’s experience, or is experience mostly a permissive factor? We will also consider whether there is a switch in sensory plasticity as development proceeds from the pre-sensory period (before eye opening) to the onset of sensory experience, and show deficits in temporal processing in animals that experienced premature visual experience.