The sensorimotor stage is the first of the four stages in Piaget’s theory of cognitive development. It extends from birth to approximately 2 years and is a period of rapid cognitive growth.
This stage is characterized by the infant’s reliance on their senses and motor actions to understand and interact with the world.
During this period, infants progress from simple reflex-driven behaviors to increasingly complex and intentional actions, gradually constructing a foundational understanding of objects, space, causality, and time.
Key Characteristics of the Sensorimotor Stage (birth to ~2 years):
- Sensory and Motor Exploration: Infants learn by using their senses (sight, touch, sound, etc.) and motor actions (grasping, crawling, etc.) to interact with the environment.
- Object Permanence: They develop the understanding that objects continue to exist even when out of sight — a major cognitive milestone.
- Cause and Effect (Causality): Infants begin to understand that their actions can cause specific outcomes (e.g., pressing a button makes a sound).
- Development of Schemas: Through repeated experiences, infants build basic mental frameworks (schemas) that help them understand and predict the world.
- Emergence of Symbolic Thought: Toward the end of this stage, infants begin to use mental representations and engage in simple pretend play (e.g., using a banana as a phone).
How do infants learn during the sensorimotor stage?
Infants learn through a process that integrates sensory processing (seeing, hearing, touching) and motor skills (grasping, crawling), allowing them to interact with and interpret their environment.
As they touch, see, hear, and move, they engage in exploration behavior, such as grasping objects, mouthing toys, or crawling toward sounds.
These repeated interactions form the basis of sensorimotor learning, where infants begin to recognize patterns and outcomes (e.g., shaking a rattle makes a sound).
Through this active engagement, infants gradually build schemas, mental structures that help them organize and make sense of their experiences.
For example, an infant might develop a schema for “grasping” that can be adapted to different objects, or a schema for “dropping” that helps them explore gravity and cause-effect relationships.
This cycle of action and feedback is fundamental to cognitive development during the sensorimotor stage.
Why the sensorimotor stage matters
The sensorimotor stage is critical because it shows how early experience shapes brain development.
During this period, every touch, sound, and movement helps form neural connections that are essential for later cognitive growth.
It also lays the foundation for key abilities such as language, memory, and problem-solving.
For example, when infants start to remember where a toy is hidden (memory), imitate sounds (language), or figure out how to reach a desired object (problem-solving), they are building the mental tools needed for more complex thinking in later stages.
Because of its foundational role, the sensorimotor stage is a key focus in parenting strategies, early childhood education, and developmental psychology research.
Understanding it helps caregivers and professionals support healthy development right from birth.
What To Look Out For In Your Child
As you navigate the early years of parenting, you’ll notice many little signs that your child is developing new ways of thinking and understanding the world.
One important milestone is object permanence —when your child realizes things (and people) still exist even if they’re not visible.
You’ll notice this when your child stays calm as you leave the room, confident that you haven’t disappeared forever.
This understanding helps your child feel secure during separations, making transitions easier and helping them feel comfortable with other familiar caregivers.
Another big step you’ll observe is their growing understanding of cause and effect.
Initially, this might look like deliberately dropping food or splashing water in the bath, just to see what happens.
As they get older and understand this idea better, they’ll interact more purposefully with toys and objects—like pressing a specific button repeatedly because they enjoy the sound it makes.
These behaviors show they’re beginning to connect their actions with specific outcomes, a crucial part of their cognitive growth.
How does cognitive development progress from reflexes to symbolic thought in infancy?
Cognitive development in infancy begins with sensorimotor intelligence, where newborns interact with the world through basic reflexes such as sucking and grasping.
As infants grow, these reflexes evolve into more intentional behaviors, forming the foundation of mental schemas – organized patterns of action or thought used to understand and respond to experiences.
Through repeated exploration and interaction, these schemas become more complex.
Infants begin to understand cause-and-effect, develop object permanence, and eventually form internal mental representations of objects and events.
This marks the shift toward representational thought, where thinking is no longer tied to direct sensory input or physical actions.
By the end of the sensorimotor stage (around 18–24 months), children engage in symbolic play, demonstrating their ability to use one object to represent another – an early sign of abstract thinking.
All of this cognitive growth is supported by rapid brain development, particularly in areas related to memory, problem-solving, and symbolic processing.
Developmental Milestones
The schemas constructed during this period provide the foundation for more complex and abstract thinking that will emerge in later stages.
The understanding of objects, space, causality, and time that develops during the sensorimotor stage serves as the basis for the child’s developing worldview and their capacity for reasoning and problem-solving.
1. Reflexes
- What It Means:: This is the earliest phase of development where infants respond to the world through automatic, inborn reflexes like sucking, grasping, and blinking. These actions aren’t yet under conscious control but are the basic building blocks for later voluntary behaviors.
- When It Happens: Reflexive behavior is dominant from birth to about 1 month of age. At this stage, babies aren’t intentionally exploring — they’re reacting to stimuli through natural reflexes.
- Why It’s Important: These reflexes help babies survive (e.g., sucking for feeding) and form the foundation for more coordinated, intentional actions that emerge in later substages.
- Signs to Watch For: Look for automatic responses such as sucking when something touches the roof of the mouth, or grasping your finger when it touches the palm. These are signs that reflex pathways are active and functioning normally.
2. Imitation
- What It Means: Imitation is when infants copy the actions, facial expressions, or sounds they observe in others. Early imitation is often simple (like sticking out the tongue), but by the end of the sensorimotor stage, it includes more complex, delayed imitation — repeating actions after a delay.
- When It Happens: Basic imitation appears in the first few months of life. More advanced or delayed imitation emerges around 18 to 24 months, as toddlers begin to form mental representations of what they see and can copy it later.
- Why It’s Important: Imitation is key for learning social behaviors, language, and problem-solving. It shows that infants are beginning to understand and remember what others do — an early sign of symbolic thinking and cognitive growth.
- Signs to Watch For: Notice if your child copies gestures, like clapping, waving, or pretending to talk on the phone after seeing you do it. Delayed imitation — like mimicking an action they saw hours earlier — is a major developmental milestone.
3. Object Permanence
- What It Means: The realization that objects continue to exist even when they’re out of sight.
- When It Happens: This understanding typically begins to emerge around 4 to 7 months of age. By 8 months, many babies begin to show clearer signs of this realization, though a complete understanding usually solidifies by 18-24 months.
- Why It’s Important: It’s the starting point for memory skills and realizing that things around them are constant. It also builds the foundation for trust and attachment (knowing caregivers will return).
- Signs to Watch For: Your baby enjoys games like peek-a-boo and will look for toys you’ve hidden, showing they know it’s still there. They may cry when you leave the room, not because they’ve forgotten you, but because they now know you still exist and want you back. Infants begin visually tracking moving objects that temporarily disappear and reappear.
4. Cause and Effect
- What It Means: Infants begin to recognize that specific actions lead to specific outcomes. For example, shaking a rattle makes a sound or dropping a toy causes a reaction from a parent. This is known as developing an action-outcome relationship, a core element of cause and effect reasoning.
- When It Happens: Babies start showing initial signs of grasping cause and effect between 4 to 8 months. This understanding deepens and becomes more sophisticated throughout the sensorimotor stage and beyond.
- Why It’s Important: It lays the groundwork for logical thinking by helping babies recognize patterns between their actions and outcomes. This awareness encourages early problem-solving as infants begin to test possibilities and anticipate results. It also plays a key role in learning theory, particularly operant conditioning, where behavior is shaped by its consequences. Most importantly, it fosters a growing sense of agency — the realization that their actions can influence the world around them — which is crucial for motivation and confidence in learning.
- Signs to Watch For: You might see your baby dropping toys from their high-chair repeatedly, not just for fun, but also to see what happens and to get your attention. They press buttons, bang objects, or splash water, watching for results.
5. The Start of Pretend Play
- What It Means: Using one object to stand in for another (like pretending a banana is a phone), showcasing the onset of imaginative play. This behavior reflects the development of mental representation, where children can hold ideas in their minds and manipulate them symbolically.
- When It Happens: Pretend or symbolic play usually begins around 18 months but becomes more pronounced and complex by the age of 2 years. This is when children start using objects to represent something else, like pretending a banana is a phone or a box is a car.
- Why It’s Important: This imaginative play shows they’re starting to think in creative ways and is a foundation for language skills. As children act out scenarios, name pretend objects, and assign roles, they are building the foundation for later conceptual thinking and communication.
- Signs to Watch For: Watch for moments when your child uses one object to represent another, like using a bowl as a hat or a box as a car. They show growing interest in role play, storytelling, or copying adult behaviors in playful ways. Infants begin to act out simple scenarios, like feeding a doll or putting a stuffed animal to bed.
Sub-Stages
The sensorimotor stage of development can be broken down into six additional sub-stages including:
- Reflexive Schemes: Newborns rely on innate reflexes like sucking, grasping, and blinking to interact with their environment. These automatic responses form the foundation for later voluntary behaviors.
- Primary Circular Reactions: Infants begin to repeat actions centered on their own body that bring pleasure, such as sucking their thumb. These behaviors are discovered by chance and then intentionally repeated.
- Secondary Circular Reactions: Babies start to focus on the external environment, repeating actions that produce interesting effects, like shaking a rattle. Learning becomes more about the outcome of interacting with objects.
- Coordination of Secondary Circular Reactions: Infants begin to combine actions purposefully to achieve goals, such as pushing a toy aside to grab another. This stage marks the beginning of intentional problem-solving.
- Tertiary Circular Reactions: Toddlers act like little scientists, experimenting with different actions to observe varied outcomes, such as dropping objects in new ways. This reflects growing curiosity and flexible thinking.
- Mental Representation: Children develop the ability to form mental images of objects and events, leading to symbolic thought and pretend play. They can now solve problems mentally rather than through trial-and-error.
1. Reflex Acts (Reflexive Schemes: 0–1 month)
In their first month, babies naturally react to the world around them through automatic behaviors called reflexes.
These aren’t actions they think about or plan—babies simply respond instinctively.
Common reflexes include sucking, grasping your finger tightly, and looking toward sounds or movements.
A familiar example is the rooting reflex: if you gently stroke your baby’s cheek or lips, they automatically turn their head toward your hand and open their mouth, ready to feed.
This reflex helps newborns breastfeed and shows how babies are born with built-in responses to support survival and early development.
2. Primary Circular Reactions (1–4 months)
Between 1 and 4 months, babies start repeating simple actions with their own bodies that feel good or comforting.
For example, your baby might suck their thumb or kick their legs repeatedly because they enjoy the sensation.
Initially, these actions happen by accident, but your baby continues doing them because they find them pleasurable.
The term “circular” refers to how babies repeat these enjoyable actions again and again.
At this stage, they’re not focused on interacting with objects or achieving specific goals; they’re simply exploring and enjoying sensations that relate directly to their own body.
3. Secondary Circular Reactions (4–8 months)
Between 4 and 8 months, babies start exploring how their actions affect the world around them.
Unlike earlier months, when their actions mainly involved their own body, they now intentionally interact with external objects.
For example, your baby might accidentally shake a rattle and enjoy the sound it makes, then shake it again purposefully to hear it again.
At this stage, their motivation shifts from enjoying sensations to seeing interesting outcomes.
They’re curious about how things work and begin to understand that their actions cause things to happen.
This growing awareness helps them discover that they can influence their environment, marking an important step in their development.
4. Co-ordinating Secondary Reactions (8–12 months)
From around 8 to 12 months, babies begin combining multiple actions to reach a specific goal, even when the solution isn’t immediately obvious.
They’re starting to use what they’ve learned to solve simple problems in a planned way.
For example, if your baby sees a toy they want but can’t reach it directly, they might pull on a cloth underneath the toy to bring it closer.
This shows they’re using one action (pulling the cloth) as a way to accomplish another action (grabbing the toy).
This ability to coordinate different actions is a big step forward.
It indicates they’re starting to think ahead, intentionally solving problems by connecting actions together.
It also helps them understand relationships between actions and outcomes, which is crucial for developing more advanced thinking skills.
Why Coordinating Actions Matters (8–12 Months):
At this stage, your baby’s ability to combine different actions is a big milestone because it means they’re starting to:
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Act intentionally: Your baby can now clearly use one action to achieve another, showing they have specific goals in mind when they act.
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Solve problems: They’re beginning to overcome simple challenges by using actions they’ve learned before in new ways, adapting and combining them to find solutions.
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Understand relationships: Your baby starts understanding how things relate to each other, like how objects and actions fit together in space and time, setting the stage for more advanced thinking and learning in the future.
5. Tertiary Circular Reactions (12–18 months)
Between 12 and 18 months, toddlers become little explorers, actively experimenting with objects around them to see what new effects or discoveries they can make.
Unlike earlier stages, when they mostly repeated known actions, now they’re curious about how and why things happen.
At this stage, your child deliberately tries different actions – like dropping toys from different heights, tipping over containers, or mixing things—to test outcomes.
They use trial-and-error to learn about their surroundings, driven by a natural interest in understanding and exploring the world in new ways.
Key characteristics of tertiary circular reactions:
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Curiosity and Exploration: Your child intentionally tries new ways of interacting with objects to see what different effects they can produce. They actively explore concepts like gravity or how objects move when dropped or thrown.
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Varied Actions and Testing: Instead of repeating the same action over and over, your child changes their approach to discover new outcomes. They might vary how high they drop a toy or how forcefully they push something, exploring the differences in results.
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Interest in Objects’ Qualities: Toddlers at this age start paying close attention to what makes objects unique. They want to understand objects’ specific characteristics, behaviors, and possibilities, viewing each object as something interesting and distinct in itself.
Examples of tertiary circular reactions:
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Dropping toys from different heights: Your child might repeatedly drop toys from various heights, noticing differences in the sound, speed, and how the objects land. This helps them explore how height affects falling.
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Tilting boxes to see what happens: They might tip or shake boxes at different angles to observe how items move or spill out. This teaches them about stability, balance, and spatial relationships.
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Testing which objects float or sink: During bath time, your toddler might experiment with different items to see which float and which sink, learning about buoyancy and water properties.
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Pouring water between cups: Your child might pour water from one container into another, watching closely how the water flows or fills differently shaped containers. This shows they’re exploring how liquids behave and beginning to understand concepts like volume.
6. Mental Representation (18–24 months)
Between 18 and 24 months, toddlers begin using symbolic thought—imagining things even when they’re not directly in front of them.
This is a huge developmental step that sets the stage for the next phase of growth.
At this age, your child can form mental pictures of people, objects, or events, allowing them to think about and remember things they can’t currently see.
This new ability leads to imaginative play, where they might pretend a block is a phone or a box is a car.
Symbolic thinking also means your child understands that things exist even when hidden from view (object permanence).
This skill lays the groundwork for future learning, supporting language development, creativity, and problem-solving abilities.
How To Help Your Child During This Stage
The sensorimotor stage (birth to ~2 years) is when babies learn through movement and sensory exploration.
You don’t need fancy toys — everyday interactions and simple materials can have a big impact.
It’s about creating opportunities for hands-on exploration, movement, and meaningful interaction.
🧠 1. Stimulate the Senses with Diverse Materials
Infants learn by processing sensory input — through touch, sight, sound, smell, and taste.
Offering a variety of sensory experiences strengthens their brain connections and builds foundational understanding of the world.
What to do:
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Provide materials with different textures (e.g., soft fabric, rubbery teethers, wooden spoons).
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Let them play with sound-producing toys like rattles, musical instruments, or crinkly paper.
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Create safe taste exploration by offering age-appropriate foods with varied flavors and textures.
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Use sensory bins with rice, pasta, or water (supervised) to explore through scooping, pouring, and feeling.
🦶 2. Support Gross and Fine Motor Development
Movement is central to sensorimotor learning.
As babies learn to control their bodies, they explore more freely and with greater intention.
What to do:
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Offer tummy time daily to build core strength and prepare for crawling.
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Place toys just out of reach to encourage reaching, rolling, and crawling.
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Provide opportunities to stand and cruise along furniture for older infants.
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Use stacking rings, nesting cups, or shape sorters to promote fine motor skills and coordination.
👁️ 3. Build Object Permanence Through Simple Games
Developing object permanence — knowing that things exist even when out of sight — is a key cognitive leap in this stage.
What to do:
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Play peekaboo with your hands, a cloth, or a favorite toy.
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Hide small toys under cups or behind furniture and encourage your child to find them.
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Use picture books with flaps or windows that “reveal” hidden images.
Why it matters:
This helps babies understand that people and objects don’t vanish just because they’re out of sight, which builds memory and trust.
🧪 4. Encourage Cause-and-Effect Learning
Infants begin to understand that their actions can influence the environment.
This is crucial for learning agency, problem-solving, and scientific thinking.
What to do:
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Let them press buttons that make sounds, flip light switches, or turn knobs.
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Set up water play with cups, sponges, and floating toys to experiment with pouring and squeezing.
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Give toys that react (e.g., pop-up toys, wind-up animals, stack-and-drop games).
Why it matters:
These repeated experiments help children learn predictability and control, forming early problem-solving skills.
🗣️ 5. Talk, Sing, and Engage in Social Interaction
Language and cognition develop together. Even before they speak, babies are learning how communication works through imitation, tone, rhythm, and turn-taking.
What to do:
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Narrate daily activities with rich, descriptive language.
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Sing songs with hand motions, like “Itsy Bitsy Spider” or “Wheels on the Bus.”
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Imitate your baby’s coos, gestures, or facial expressions to show them their communication has value.
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Read simple picture books, even if they just mouth or point at the pages.
Why it matters:
These interactions build social bonds, strengthen language processing, and teach basic conversation patterns.
🎭 6. Introduce Symbolic and Pretend Play (18–24 Months)
Toward the end of the sensorimotor stage, toddlers begin to use objects symbolically — an important sign of emerging abstract thinking.
What to do:
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Offer open-ended objects for imaginative use: blocks, cups, cardboard boxes.
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Encourage pretend scenarios (e.g., feeding a doll, talking on a toy phone).
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Join in! Modeling imaginative play supports language, empathy, and creativity.
Why it matters:
Symbolic thought underlies future skills like storytelling, reading, and problem-solving.
🧸 7. Provide Safe, Repetitive Experiences
Children in this stage learn best through repetition — doing the same action again and again builds understanding and confidence.
What to do:
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Allow them to repeat actions like dropping spoons, knocking over blocks, or splashing in water.
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Rather than rushing to interrupt or correct, observe and support their process.
💡 Final Thought:
The most powerful way to support sensorimotor development is to be present, responsive, and playful.
Follow your child’s lead, create a safe space to explore, and turn everyday routines — diaper changes, meals, bath time — into opportunities for connection and learning.
References
Corman, H. H., & Escalona, S. K. (1969). Stages of sensorimotor development: A replication study. Merrill-Palmer Quarterly of Behavior and Development, 15(4), 351-361.
Dunst, C. J. (1988). Stage transitioning in the sensorimotor development of Down’s syndrome infants. Journal of Intellectual Disability Research, 32(5), 405-410.
Flanders, M., Tillery, S. I. H., & Soechting, J. F. (1992). Early stages in a sensorimotor transformation. Behavioral and Brain Sciences, 15(2), 309-320.
Lösche, G. (1990). Sensorimotor and action development in autistic children from infancy to early childhood. Journal of Child psychology and Psychiatry, 31(5), 749-761.
Piaget, J. (1952). The origins of intelligence in children. New York: International Universities
Press.
Piaget, J. (1954). The construction of reality in the child. New York: Basic Books.
Piaget, J. (1964). Part I: Cognitive development in children: Piaget development and learning. Journal of research in science teaching, 2(3), 176-186.
