Sensorimotor Stage

We can all agree that babies don’t know how to do a lot. But they grow fast. If you’ve ever taken care of an infant or a 1-year-old, you see how fast they develop and learn how to crawl, walk, and take in the world around them. 

What Is the Sensorimotor Stage?

From birth to the age of 2, babies are in the sensorimotor stage of cognitive development. This stage is the first of four stages in Jean Piaget’s Theory of Cognitive Development. The sensorimotor stage has six substages within this one stage. 

object permanence in the sensorimotor stage

Ready? Let’s get started by talking about object permanence. 

Object Permanence

Before we break down the six substages of the sensorimotor stage, I want to talk about object permanence. If you only take away one thing from this video, it should be the concept of object permanence and the idea that it develops during this initial stage of cognitive development. 

Object permanence is the idea that objects exist, even when they are out of your sight or hearing. When babies cry for their parents, they don’t realize that they are just one room over. Once the parent is gone from sight, the baby believes they are gone forever. During the course of the sensorimotor stage, they begin to realize that their parents still exist, even if they are out of the baby’s sight. 

This is why peek-a-boo is so fun with babies! They may literally think that you have gone missing when you put a blanket over your face or hide underneath a table. 

The Six Substages of The Sensorimotor Stage

  • Reflex Acts
  • Primary circular reactions
  • Secondary circular reactions
  • Coordination of secondary circular reactions
  • Tertiary circular reactions
  • Mental combinations 

Stage 1: Reflex Acts 

Object permanence is one of the more advanced parts of cognitive development in this stage. Now, let’s break down the basics and start with the first substages that babies go through during the sensorimotor stage. 

The first substage is called Reflex Acts, and it lasts until the baby is around one month old. We think of reflexes as things that we do automatically. In the Theory of Cognitive Development, reflexes come under the umbrella of schemas, or concepts that help us interact with the world around us. 

The first reflexes that babies are born with help the baby breastfeed. These schemas are essential to the child’s survival. During this stage, the child learns how to develop these reflexes and more easily survive through breathing, feeding, and swallowing. 

Stage 2: Primary circular reactions

Between the ages of one month and four months, the child enters a second substage of the sensorimotor stage. The biggest difference between the first and second substages is that movements become voluntary. The child begins to connect reflexes with pleasurable feelings. They start to repeat that movement to feel that pleasure once again. Through this coordination, and awareness, they start to gain more control over their physical body. 

However, these movements and reflexes only come from movements that they have experienced. Infants are not predicting what will feel good or experimenting within their body. They are simply reacting to a pleasurable sensation and repeating the reflexes that brought on that pleasurable sensation. 

Research on babies and their brains shows that the cerebral cortex (including sensory and motor cortex) dramatically develop during this stage of life.

Stage 3: Secondary circular reactions

From the ages of four to eight months, the learning starts to move outside the infant’s body. In the primary circular reaction stage, the infant is solely focused on sensations within their body (hand in the mouth, hands together, etc.) Now, the infant is starting to focus on other objects or things outside of their body. 

At this stage, the baby may find more interest in toys, rattles, etc. Again, this stage of learning is all reacting to reflexes. Nothing here is planned. The infant may accidentally hit a rattle on the floor, enjoy the sensation, and then repeat the sensation to invoke the same pleasurable sensation. Nothing is predicted. 

This is when the schema of object permanence starts to develop. 

Stage 4: Coordination of secondary circular reactions

Babies begin cognitive development solely through accidental reflexes that invoke certain sensations. At stage 4 of the sensorimotor stage, babies begin to learn schemas through observation and through combining schemas that they have already collected. This stage lasts from about eight months to the child’s first birthday. 

At this point, you might start to see the babies repeating the objects of their parents. They might also start to intentionally and voluntarily move with a specific goal in mind. Babies also start to understand words at this stage. 

Stage 5: Tertiary circular reactions (aka deliberate learning)

At this stage of the baby’s cognitive development, they start to experiment. From around the ages of 12-18 months, the baby begins to try out different variations of movements and schemas that they have learned. They aren’t just able to intentionally move with a goal in mind. They are able to try different forms of movement to achieve a goal or simply to see what the consequences are. 

In a way, babies are like little scientists during this stage. They may have a goal: to get a hug from mom. (Remember, they have developed object permanence. Even if the mom is in the other room, the baby may still try and get a hug or a reaction from the mom.) The baby may first cry – and see what happens. They may coo – does mom come into the room then? What about when the baby throws the objects next to them across the room or shake their rattle? 

baby shaking a rattle

Babies are likely to speak their first words at this stage. Since they have developed the idea that their words have consequences, they may repeat words that have invoked a positive response from the parent. 

Stage 6: Mental combinations (aka beginnings of symbolic thought) 

We’ve arrived at the last substage of the sensorimotor stage. From the ages of around 18 months to two years, the toddler begins to develop and recognize symbols. They may connect a stuffed animal of a dog with an actual dog that they have interacted with. At this stage, the baby may be starting to use their thoughts, rather than just physical actions, to understand what is happening around them. 

What Comes After the Sensorimotor Stage? 

Phew! This is just one stage of Piaget’s Theory of Cognitive Development. ​After this, the child will go through three other stages of cognitive development:

piaget's stages of cognitive development

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