The Sensorimotor Stage
The first stage in Piaget’s theory is the sensorimotor stage, which lasts from birth to about 2 years old. During this stage, children learn about the world through their senses and motor behavior. For example, children put objects in their mouths to see if the items are edible, and once they can grasp objects, they may shake or bang them to see if they make sounds.
the sensorimotor stage
Piaget divided the sensorimotor stage into six substages that show the progression from reflexive responses to intentional, goal-directed behavior:
- Reflexes (Birth to 1 month) Newborns learn through innate reflexes such as sucking, grasping, and rooting. These automatic responses become more deliberate with practice.
- Primary Circular Reactions (1 to 4 months) Infants begin repeating actions involving their own bodies that produce pleasurable results, such as sucking their thumb or kicking their legs.
- Secondary Circular Reactions (4 to 8 months) Infants repeat actions that affect their environment and produce interesting results, such as shaking a rattle to hear the sound or kicking a mobile to make it move.
- Coordination of Secondary Circular Reactions (8 to 12 months) Infants combine actions to achieve goals and show intentional, planned behavior. For example, they might push aside a blanket to reach a hidden toy. Object permanence begins to emerge during this substage.
- Tertiary Circular Reactions (12 to 18 months) Toddlers become “little scientists,” experimenting with new actions to see different outcomes. They use trial-and-error to explore objects in varied ways, such as dropping items from different heights to observe results.
- Beginning of Representational Thought (18 to 24 months) Toddlers develop symbolic thinking and can solve problems mentally before acting. They engage in pretend play, use objects to represent other things, and can remember and imitate actions they observed earlier (deferred imitation). This marks the transition to the preoperational stage.
Object Permanence: A Key Milestone
Between 5 and 8 months old (during substage 4), the child develops object permanence, which is the understanding that even if something is out of sight, it still exists (Bogartz, Shinskey, & Schilling, 2000).
According to Piaget, young infants do not remember an object after it has been removed from sight. Piaget studied infants’ reactions when a toy was first shown to an infant and then hidden under a blanket. Infants who had already developed object permanence would reach for the hidden toy, indicating that they knew it still existed, whereas infants who had not developed object permanence would appear confused.
Because toddlers (ages 12–24 months) have mastered object permanence, they enjoy games like hide-and-seek and realize that when someone leaves the room they will come back (Loop, 2013). Toddlers also point to pictures in books and look in appropriate places when you ask them to find objects.
You can view the transcript for “Piaget – Stage 1 – Sensorimotor Stage : Object Permanence” here (opens in new window).
Stranger Anxiety
Around the same time that children develop object permanence, they also begin to exhibit stranger anxiety, which is a fear of unfamiliar people. Babies may demonstrate this by crying and turning away from a stranger, by clinging to a caregiver, or by attempting to reach their arms toward familiar faces such as parents.
Stranger anxiety results when a child is unable to assimilate the stranger into an existing schema. Therefore, they can’t predict what their experience with that stranger will be like, which results in a fear response.
Criticisms of Piaget
Although Piaget’s theory has been very influential, it has not gone unchallenged. Many more recent researchers have obtained findings indicating that cognitive development is considerably more continuous than Piaget claimed.
For example, Diamond (1985) found that on the object permanence task described above, infants show earlier knowledge if the waiting period is shorter. At age 6 months, they retrieve the hidden object if the wait is no longer than 2 seconds; at 7 months, they retrieve it if the wait is no longer than 4 seconds; and so on.
In addition to rapid physical growth, young children also exhibit significant development of their cognitive abilities. Piaget thought that children’s ability to understand objects—such as learning that a rattle makes a noise when shaken—was a cognitive skill that develops slowly as a child matures and interacts with the environment. Today, developmental psychologists think Piaget was incorrect. Researchers have found that even very young children understand objects and how they work long before they have experience with those objects (Baillargeon, 1987; Baillargeon, Li, Gertner, & Wu, 2011).
For example, children as young as 3 months old demonstrated knowledge of the properties of objects that they had only viewed and did not have prior experience with them. In one study, 3-month-old infants were shown a truck rolling down a track and behind a screen. The box, which appeared solid but was actually hollow, was placed next to the track. The truck rolled past the box as would be expected. Then the box was placed on the track to block the path of the truck. When the truck was rolled down the track this time, it continued unimpeded. The infants spent significantly more time looking at this impossible event (Figure 2). Baillargeon (1987) concluded that they knew solid objects cannot pass through each other. Baillargeon’s findings suggest that very young children have an understanding of objects and how they work, which Piaget (1954) would have said is beyond their cognitive abilities due to their limited experiences in the world.
Similarly, children’s specific experiences can greatly influence when developmental changes occur. Children of pottery makers in Mexican villages, for example, know that reshaping clay does not change the amount of clay at much younger ages than children who do not have similar experiences (PPrice-Williams, Gordon, & Ramirez, 1969).