In order to learn about the world and the things in it, we must explore our surroundings and gather information through our senses. Regardless of whether we are talking about a child or adult, or a developmentally delayed or gifted individual, and regardless of the skill or concept we are considering, the brain must begin its search for information by using the senses.
If we do not recognize something as having been encountered in the past or if we encountered it but did not understand it, we will rely on our sensory organs to gather information. Both children and adults who are presented with something completely novel to them will begin their investigation by looking, touching, tasting or listening to it. It is only after we have gained information about the physical properties of the thing we are exploring that we can move on to investigating it at a more sophisticated level.
Because sensory exploration is the foundation of all learning, individuals who have visual or hearing impairments and those who have inadequate sensory integration or sensory processing abilities are at a great disadvantage and are therefore at higher risk for experiencing delayed development and learning disabilities.
All skills and concepts follow the same sequence of developmental stages: acquiring information about something's physical properties by exploring it with the sensory organs, discovering how these properties change when an action is taken (cause and effect relationships), and the ability to manipulate this information symbolically in the mind in the absence of the thing itself.
Children with atypical development progress through the same stages of concept development and in the same order as children with typical development. Due to the sensory processing problems that the atypical population experiences, however, they often cannot progress as fast through these stages and can become stuck in a stage for years, perhaps even indefinitely, if they are unable to gain access to the information and experiences they need in order to progress to the next higher level.
The fist two stages of skill or concept development (we call this "cognitive" development) are the sensory stages. In the first stage the learner uses only one sense at a time to explore something. Stage One is marked by behaviors like watching but not touching or looking away from something that is being manipulated by the hands.
Stage Two is marked by exploration behaviors that show the coordination of two or more senses: an object an be manipulated at the same time it is being watched or it can be mouthed at the same time it is being manipulated with the fingers.
The sensory stages illustrate the progression from "simple to complex" and from "single to multiple" that will mark all of the stages of cognitive development. In language development, for example, infants vocalize and produce individual sounds, grunts, or squeals before they produce more complex constructions like combining consonants and vowels ("canonical babbling"). In the same way, children first explore individual physical properties of things before they can coordinate their senses well enough to explore two or more dimensions of an object at once.
We can think of the process through which brains gather information from sensory exploration as like stringing beads to create a necklace. Individual bits are collected and strung together one after the other before the pattern appears. In the next article we will explore how brains move from collecting information about the sensory properties of objects to considering how those properties might change when an action is performed (e.g. exploring cause and effect). It is in this next level of cognitive development that the brain will move beyond a simple fact gathering machine to higher level cognitive abilities like imagination, creativity and attaching symbols with meaning, While the first two stages of sensory exploration form the foundation of all learning, it is in the next three "cause and effect" stages that higher level cognitive abilities begin to appear.