In the field of developmental psychology, the everyday family scene of a child using a spoon to access a distant toy holds surprisingly profound implications. It exemplifies the respected Swiss psychologist Jean Piaget’s paradigm of ‘cognitive development’. This theory, which continues to have a strong influence on our understanding of how children develop, is anchored around four cornerstone stages: ‘the sensorimotor stage‘, ‘preoperational stage‘, ‘concrete operational stage‘, and ‘formal operational stage‘. This article will focus on the intricate pathways of the sensorimotor stage.
Babies acquire understanding of their surroundings through the tangible activities they engage in, beginning with reflexive responses from birth, often in response to sounds and visual stimulus, and evolving into early symbolic thinking in relation to physical acts, such as using their hands or mouths to hold onto something they desire. From the first few vulnerable days and through their journey to the emergence of language, infants combine these sensory experiences with corresponding actions to decode the new and unfamiliar world around them. This stage of development is punctuated by observable progressions ranging from recognizing a familiar person to understanding that pictures and drawings can represent real objects or actions.
A good example of the progression of the sensorimotor stage is the well-known game in which an adult, hiding their face behind their hands or another object, suddenly reveals themselves in order to try and attract laughter or a surprised reaction from the baby or child. This game, played in cultures across the world, offers a window into a child’s cognitive development. Their expression of surprise or delight upon the ‘reappearance’ of the familiar face indicates that they are still in the process of grasping the concept of ‘object permanence‘, which is the understanding that things, like a hidden face, continue to exist even when out of sight (2).
Another well-known demonstration of a child’s growing understanding of object permanence is the ‘hidden toy’ experiment, which is also linked with Jean Piaget’s studies on cognitive development. In this game, a favoured toy is presented to the child. While the child observes, the toy is discreetly hidden under a blanket or behind some barrier. Young infants, still in the early stages of understanding object permanence, might behave as though the toy has vanished once it is concealed from view. However, as babies mature, they begin to attain a deeper understanding of both their own existence (sense of self) and the consistent existence of objects around them. Typically, by the age of 8 to 12 months, many children will actively seek out objects that have been hidden, illustrating their developing comprehension of object permanence (5). Similarly, the child now knows that a hidden face still exists behind an adult’s hands, rendering the game’s surprise element redundant. These shifts in understanding are, therefore, tangible markers of a significant cognitive milestone in a child’s understanding of the world.
As the sensorimotor stage progresses, we observe another distinct behaviour, described by Piaget as ‘directed groping’. Rather than being passive recipients of their environment, children start to actively engage with their surroundings, developing an innate curiosity. Through such interactions, such as using a spoon to access a distant toy, children not only refine their motor skills but also begin to hone problem-solving abilities. With each exploratory action, whether it be reaching for an object or manipulating it, a foundational stone is laid for more advanced cognitive tasks.
Piaget’s sensorimotor stage, which spans from birth to approximately 2 years of age, can be broken down into six distinct substages. These substages detail the progression of an infant’s cognitive development during this period.
Substage 1: Reflexes (Birth to 1 Month)
When a soft object brushes against a baby’s palm, they tend to instinctively grasp it with their fingers. Alternatively, if you stroke the cheek of a newborn baby, you will probably observe that they automatically turn their head towards the source of the touch. Such reactions are not coincidences but are in fact rooted in the essence of early human development. During the first few weeks of life, these behaviours reveal that newborns operate largely based on innate reflexes, which are automatic and natural responses to specific external stimuli. These reflexive actions, products of evolution, are essential for the child’s immediate survival. With time, the infant starts adjusting some of these reflexes in response to their surroundings, like distinguishing between varying tactile experiences. At the same time, certain initial reflexes, such as the spontaneous curling of toes when touched, begin to decrease as the infant progresses in age (3).
Substage 2: Primary Circular Reactions (1–4 Months)
During this period, infants primarily focus on their own bodies and repeatedly engage in what Piaget labelled primary behaviours. These tend to be discovered by accident, such as thumb-sucking, which is repeated due to the pleasure derived. Over time, reflexes evolve into more deliberate actions, and infants start coordinating these actions better, like grasping an object and then bringing it to their mouth. This stage marks the transition from purely reflexive behaviours to more intentional, albeit self-centred, interactions with their environment (4).
Substage 3: Secondary Circular Reactions (4–8 Months)
At this stage infants become more responsive and increasingly shift their focus from themselves to the external world. This heightened awareness marks a transition from primary to secondary behaviours, and infants start recognising the impact of their actions on surrounding objects. For example, an infant might repeatedly knock over their bottle, only to express concern each time it disappears, even when it is quickly returned by an adult. Although they seem engrossed by the outcomes of their behaviours, the child’s grasp on direct cause-and-effect relationships remains primitive.
Substage 4: Coordination of Secondary Circular Reactions (8–12 Months)
Here, infants begin to exhibit goal-directed behaviour, as they purposefully combine known actions to achieve desired outcomes. As mentioned earlier, an example of this is using one object to interact with another, like using a stick to retrieve a toy. This is significant as it highlights their growing problem-solving skills and comprehension of means-end relationships. Furthermore, children at this stage tend to develop an understanding of object permanence, the idea that objects still exist even when out of sight. The leads to them learning to actively search for hidden items, a skill which lays the groundwork for the eventual emergence of symbolic thought (6).
Substage 5: Tertiary Circular Reactions (12–18 Months)
In this phase, infants tend to display a heightened sense of curiosity and engage more in creatively exploring their own environment. They start experimenting with objects in new ways, which leads to a trial-and-error approach. Instead of repeating familiar actions with objects, they try out new actions in order to witness different outcomes (the word tertiary in the title of this substage signifies that children are moving onto a new stage of development). For example, a child might vary the way they throw a toy or manipulate it differently so that they can observe the results. This marks the beginning of the child’s ability to flexibly adapt to new situations and shows an evolution in their problem-solving skills. Piaget exemplified this stage in a child’s development by writing about his 14-month-old daughter:
Jacqueline holds in her hands an object which is new to her; a round, flat box which she turns all over, shakes, rubs against the bassinet, etc. She lets it go and tries to pick it up. But she only succeeds in touching it with her index finger, without grasping it. She nevertheless makes an attempt and presses on the edge. The box then tilts up and falls again. Jacqueline, very much interested in this fortuitous result, immediately applies herself to studying it….
Jacqueline immediately rests the box on the ground and pushes it as far as possible (it is noteworthy that care is taken to push the box far away in order to reproduce the same conditions as the first attempt, as though this were a necessary condition for obtaining the result). Afterward Jacqueline puts her finger on the box and presses it. But as she places her finger on the center of the box she simply displaces it and makes it slide instead of tilting it up. She amuses herself with this game and keeps it up (resumes it after intervals, etc.) for several minutes. Then, changing the point of contact, she finally again places her finger on the edge of the box, which tilts it up. She repeats this many times, varying the conditions, but keeping track of her discovery: now she only presses on the edge! (1 p. 272).
Substage 6: Mental Representation (18–24 Months)
In the final substage of Piaget’s sensorimotor theory, children begin to develop the ability to form internal mental images of objects, events, and actions. They can think about things without physically interacting with or seeing them, which signifies the beginning of symbolic thought. For instance, a child might use one toy to represent another in pretend play or begin to solve problems in their mind before attempting a solution. Additionally, a significant milestone during this substage is the advent of deferred imitation, where a child observes a type of behaviour and replicates it later, even in the absence of the model. Deferred imitation is an important indicator of a child’s cognitive development as it showcases their ability to store and recall memories. This not only reveals their capacity for symbolic representation and cognitive flexibility but also highlights the beginnings of social learning and empathy. Through imitating past behaviours, children demonstrate an understanding of cultural norms and an ability to apply past experiences in new contexts, eventually leading to the child learning to engage in advanced thought processes and social interactions. In summary, this stage of development heralds the transition from purely sensory-based understanding to cognitive processes that involve internal representation.
The sensorimotor stage, as conceptualized by Piaget, remains important in our understanding of early human cognitive development. Spanning from birth to around two years, this stage marks the transformation of a child from a reflex-driven infant to an individual capable of mental representation. Piaget’s theories emphasize that cognitive development is not a sudden leap but a cumulative process. The observed progression from primary reflexes to complex object manipulation and finally to symbolic thought, in which children learn to ‘think’ in a manner recognizable to adults, proves that even very young children are active learners, continually engaging with and adapting to their environment.
For parents, the described stages of the sensorimotor period offer a roadmap to their child’s cognitive milestones. For instance, a parent might notice their child’s growing awareness of object permanence when the baby starts searching for a toy hidden under a blanket instead of assuming it has disappeared. Similarly, parents may take some comfort in knowing that the delight their child takes in dropping toys repeatedly from a highchair is not necessarily bad behaviour, it might be an experiment in cause and effect.
And, while the sensorimotor stage does precede the development of formal language, it lays the foundation for later language acquisition. However, even in the absence of verbal language, infants during the sensorimotor stage engage in non-verbal communication, such as crying, and later, using gestures like pointing. These are precursors to language and are vital for communication and social interaction.
Ultimately, Piaget’s work detailing the sensorimotor stage reshaped developmental psychology, offering a foundation for subsequent research, and for modern parents and educators, it serves not just as pure academic knowledge but as a practical guide to understanding and nurturing a child’s cognitive world in their formative years.
- Piaget, J. (1952). The origins of intelligence in children. New York: International Universities Press.
- Berger, K. S. (1994). The Developing Person Through the Life Span.(ed.). V New York: Worth.
- Gruber, H. E., & Vonèche, J. J. (Eds.). (1977). The essential piaget (pp. 435-436). London: Routledge & Kegan Paul.
- Santrock, J. W., Johnson, C., & Patterson, C. (2002). A topical approach to life-span development. New York: McGraw-Hill.
- Bogartz, R. S., Shinskey, J. L., & Schilling, T. H. (2000). Object permanence in five‐and‐a‐half‐month‐old infants?. Infancy, 1(4), 403-428.
- An M, Marcinowski EC, Hsu LY, et al. Object permanence and the relationship to sitting development in infants with motor delays. Pediatr Phys Ther. 2022;34(3):309-316. doi:10.1097/PEP.0000000000000909