Ever feel like your baby has their hands on everything? Or that everything ends up in their mouth — including, dare we say it, the most unappetizing things imaginable?

Guess what — this is exactly what babies are supposed to do.

The sensorimotor stage is the first stage of your child’s life, according to Jean Piaget’s theory of child development. It begins at birth and lasts through age 2.

During this period, your little one learns about the world by using their senses to interact with their surroundings. They touch things, lick them, bang them together (with joy, we might add), and put them into their mouths. They also begin to develop fine motor skills.

Learning at this stage in life happens through experience — a wonderful and fun thing to watch.

Jean Piaget had one of the earliest voices in the field of child psychology. He’s most known for his ideas that help explain how children develop intellectually. This cognitive theory involves four stages: sensorimotor, preoperational, concrete operational, and formal operational.

Basically, he made these assumptions:

  • Children use their personal experience to develop their own knowledge about the world.
  • Children can learn on their own, even when they aren’t taught or influenced by other children or adults.
  • Children have an internal motivation to learn, so rewards for learning generally aren’t necessary.

While some criticism of Piaget’s work has surfaced over the years, experts do generally support the basic principles of Piaget’s theory. His research has contributed to greater understanding of how children learn and develop from birth through adolescence. Educators still widely use Piaget’s work to help children learn and grow in the classroom.

Piaget divided the sensorimotor period into six different substages that involve specific developmental milestones.


Your precious newborn will generally respond reflexively to touch or other stimulation, often by sucking and grasping (or even smiling!). These actions will eventually become intentional.

Primary circular reactions

This substage includes the period between 1 and 4 months. Your baby will begin to make specific movements for their own enjoyment. If they make a certain sound or movement without meaning to and enjoy how it feels, they’ll try it again and again.

Behaviors common to this stage include thumb-sucking, kicking, smiling (intentionally this time!), and cooing. We know you’re sleep deprived — but enjoy these adorable milestones.

Secondary circular reactions

From 4 to 8 months of age, your growing little one will begin to use objects to learn about the world. This process generally begins by accident, but as your baby starts to enjoy their ability to make things happen, they’ll continue these activities again and again.

They might throw or drop a toy (uh oh!), shake a rattle, or bang objects together to make delightful (at least to them) sounds. They’ll also be able to make more sounds on their own. For example, they’ll laugh, make speech-like sounds, and use sound to express happiness, excitement, or unhappiness.

Coordinating secondary circular reactions

When your child is between 8 months and a year old, they’ll begin to combine their learned abilities and reflexes to achieve goals. For example, they might crawl to pick up a toy across the room or push aside toys blocking the specific one they want. At this point, your baby is able to plan and coordinate actions in response to thoughts — so smart!

They may also:

  • enjoy simple games
  • turn and look when they hear something
  • recognize certain words and respond to them
  • say a few words or imitate your speech (though they’ll still mostly communicate with gestures such as waving or reaching)

Tertiary circular reactions

This substage occurs between 12 and 18 months, the beginning of toddlerhood. At this point, your child can explore their world and learn even more about it through motor coordination, planning, and experimentation.

They might take things apart in order to put them back together and perform certain activities again and again to see what happens each time. It’s now possible for your child carry out a series of planned actions to complete a task.

They’ll also begin to understand and respond to simple directions or questions and may begin using phrases. They may listen to or show a preference for certain short stories and songs.

Symbolic/representational thought

This final substage involves the development of symbolic thought, and it’s a big leap. According to Piaget’s theory, at 18 months children begin to understand that symbols can represent objects. This expands on the concept of object permanence — the knowledge that objects continue to exist even when they can’t be seen.

At this stage, your child can remember and repeat words or actions from previous days. Imaginative play typically begins during this period, and your child’s vocabulary will develop significantly. They might ask short questions and make requests with one or two words.

This developmental milestone is a primary goal of the sensorimotor stage. It’s your child’s ability to understand that objects and people continue to exist even when they can’t see them. It’s when your child starts to realize the things — and people, like you! — making up their world exist even when they aren’t interacting with them.

Children usually begin to grasp this concept around the age of 8 months, according to Piaget’s theory. However, this may occur as early as 6 months for some babies. (But don’t stress if your little one isn’t early or exactly on time. It doesn’t mean there’s anything wrong.)

If you’re playing with your child before they understand object permanence, you might hide a favorite stuffed animal behind your back or under a pillow. Your baby might seem horribly confused at the toy’s disappearance — for a second or two — but then appear to forget about the toy and happily move on to another one.

A child who knows the toy still exists, however, will look for it. They might crawl behind you to find it or push at the pillow to uncover it.

Object permanence also involves the knowledge that parents still exist when they temporarily leave the room. If your child cries when you step out of the room, responding to their distress can help them realize you haven’t disappeared and that you’ll come back when they need you.

Once your child understands object permanence, they may not mind when you leave the room, since they understand you’ll return eventually. (On the other hand, if they know you’re around and want you to return now… you’ll hear about it.)

Playtime helps you bond with your child while also supporting healthy cognitive growth. Many different play activities can help maximize development during the sensorimotor stage.

Here are some simple activities you can try with your child:

Object permanence play

Playing peekaboo or hide-and-seek games can help your child develop their understanding of object permanence through games. This can also help them learn cause and effect.

For younger babies, take a small blanket or cloth and hold it over your face. If your baby is old enough to grasp and pull, show them how they can pull the scarf away to reveal your face.

Then try covering baby’s face. Clapping and cheering when they pull the blanket away can help encourage their excitement about the activity. You can repeat this game with a favorite book or toy.

With a toddler, you can play a more full-body version of hide-and-seek. Hide behind a door or somewhere else they can find you easily. Call, “Where am I?” and cheer and clap when they find you. Then encourage them to hide.

Tactile play

Letting your child play with substances they can manipulate helps them learn about different sensations and develop their motor skills and creativity.

Safe, fun substances include play dough, finger paint, water, or foam balls. Make sure to supervise your child during these activities.

  • Try giving your toddler a large empty bowl, a small cup, and a smaller bowl filled with water. Encourage them to pour the water from one bowl to the others. (You may want to do this in the bathtub.)
  • Give your child different colors of play dough. Demonstrate how they can make balls and flatten them, or roll smaller balls into larger ones.
  • Show your child how to mix colors and use finger paint on paper. Teach them how they can make fingerprints or handprints. (And don’t forget to frame one of their creations or display on the refrigerator!)
  • Teaching your child how balls bounce and roll can help improve motor coordination and fine motor skills. Try balls of different shapes and colors, or balls with bells or other noisemakers inside. Encourage them to catch the balls and roll them back to you.

During this stage, spending time interacting with your child is key. Holding, feeding, and bathing your child are all essential activities that promote bonding and development — but you can also take other steps to help maximize your child’s cognitive growth.

Talk to your child frequently

Speaking to your child, even before they can answer, helps them develop language abilities and increase their vocabulary. You can talk to your child about everyday things, read to them, sing to them, and describe what’s happening during play and daily activities.

Provide environmental stimulation

During the sensorimotor stage, babies learn by using their senses to explore their environments. Providing a range of activities that involve the five senses help them develop their sensory abilities as they move through the substages. Offer your child:

  • toys with different textures and fabrics (paper, bubble wrap, fabric)
  • toys or activities that make sounds (bells, play pots and pans, whistles)
  • soft or board books with flaps or pop-ups
  • toys in different shapes, colors, and sizes
  • activities that encourage movement (stretching, reaching, crawling, grasping)

Provide supervision

Some activities are perfectly safe to let your child explore on their own. You’ll want to stay nearby, but you may not need to monitor every second of play.

For example, if you want half an hour to fold laundry at the kitchen table, you might open the kitchen cabinet where you store the pots and pans and let them bang away with a wooden spoon. (But make sure the situation is safe and they can’t get a finger or toe smashed by a heavy cast iron pot.)

Different activities may need more supervision. Play dough, for example, can quickly end up in a child’s mouth.

Babies in particular are very likely to put objects in their mouths, so you’ll want to make sure their toys are clean and safe for licking or mouthing.

And if your child keeps putting something in their mouth that isn’t safe, put it out of sight and firmly but gently redirect them to one that is. This can help them learn that only some toys are safe to put in their mouth without discouraging them from continuing to experiment with sensations.

In Piaget’s theory of cognitive development, the sensorimotor stage marks the first 2 years of a child’s life.

During this stage, your child will learn:

  • to repeat behaviors they enjoy
  • to explore their environment and interact with objects intentionally
  • to coordinate actions to achieve a specific goal
  • what happens when they repeat the same activity (cause and effect)
  • that objects still exist if they can’t be seen (object permanence)
  • to problem-solve, pretend, repeat, and imitate

Above all, your child will spend this stage learning to understand their world through experiences. Once children have the capability for representational, or symbolic, thinking — which generally occurs around the age of 2 — they have progressed into Piaget’s next stage, the preoperational stage.