Eleanor Gibson describes perceptual development in terms of infant's key elements in relation to their environment. Perceptual Development is when both the infant and the environment in which they are in evolve together, and the infant develops a sense of natural detection where they can see properties or features of the environment that are useful to them. The infant is an "active explorer" in the environment; they use their key elements (their sense of sight, touch, smell, hearing and taste) to investigate new objects, places, and things. .
The world around us is constantly changing and the infant will continuously observe the environment and how itself is in relation to the environment. With the information they get from observing they are able to act on their thoughts of objects- Gibson feels that the actions of the infant are essentially what perception is. Using their senses in experimentation an infant is able to find the affordances of objects or events and with more and more experience they begin to develop a perceptual differentiation. .
Affordances are the perceived and actual functions (properties) something in the environment has that suggest how it should be used. For example, an infant may see a wooden spoon and look at it, touch it, smell it and put it in its mouth. But only by seeing it's mother or father using the spoon to stir a pot will it develop the sense of what it actually is and how it's used. The affordances of a spoon will tell the infant one side is for holding and one side is for stirring- this tells them how they should use the wooden spoon. Whereas differentiation is the ability to selectively perceive differences between things in the environment. This occurs through learning the distinctive features of things that make them different from others. Differentiation isn't simply a way of perceiving things but a change in how we look at things, and it develops over time in which we experience and interact with the environment.