What are Piaget's stages of cognitive development?

The Sensorimotor Stage

"Wait, she's still here? No way!"
"Wait, she's still here? No way!"

The sensorimotor stage, which starts at birth and lasts until the time our child is about 2 years old, is characterized by experiences gathered primarily through sensory stimuli and motor activities (hence the name). Basically, the sensorimotor child gets most of her input through moving about and observing what's going on around her.

There are six substages in the sensorimotor stage, and each is a small incremental step toward greater awareness and participation. At first, everything is pretty much a reflexive reaction to whatever is going on. But as soon as schemata (linked sets of perceptions, ideas and actions) are under construction, she begins to have more meaningful interactions with the world.

To understand schemata, let's take a step back for a second and look a little more closely at some of the fundamental elements of Piaget's theory. Piaget said that as people are exposed to new experiences and stimuli from the external world, they seek to return their minds to a state of equilibrium by settling the new knowledge internally in a place that makes sense.

We do this with the help of two main adaptive tools that work hand-in-hand: assimilation and accommodation. Assimilation is when we fit new information into an existing schema, and accommodation is when we change or create a schema because putting the new information anywhere else doesn't make sense. Thus we have used adaptation and organization to further cognitive development, and over time, our internal mental structures become increasingly complex.

But back to our baby girl. Gradually, she grasps the idea that she can use movement to accomplish things and produce results -- this is when rattles and car keys start to get really interesting -- and so she begins to act intentionally. Also, she catches on that things still exist even when little baby isn't there to look at them; a concept called object permanence. This is what makes peek-a-boo such a fascinating game to a very young child.

Once she starts chattering away, she's moved into the second phase, which we'll read about on the next page.