Eleanor and James Gibson propose the theory of differentiation as a general principle that justifies perceptual development. This theory defends that perceptual development tends to identify invariant traits or properties in the environment. The baby's perceptual world is constantly changing and babies look for traits that remain constant. Perceptual development consists of increasing the child's sensitivity to which properties of objects and people remain stable and which vary. At the beginning of development, the information has an amodal character, but will progressively differentiate the specific sensory qualities of each modality.
