“sensorimotor stage: A developmental stage in which a child had little ability with language or the use of symbols, but experiences the world through sensation and movement. It is the first of four stages in the theory of cognitive development as described by child psychiatrist Jean Piaget. The sensorimotor stage lasts from birth until about age two.
Infants are normally born with a range of reflexes that ensures their survival, such as sucking and grasping. As the infant adapts these reflexes over time, the child can begin to interact with environment with greater efficiency. By the end of this stage, the child is able to solve simple problems, such as looking for a lost toy or communicating simple needs to a parent or another child. It is also during this stage that the infant develops a sense of object permanence—that awareness that things and people continue to exist even when they cannot be perceived. For example, before the age of two if a parent hides a toy under a pillow in front of the child, the child will not understand that the toy still exists under the pillow. Once a sense of object permanence is developed, the child will understand that the toy hidden under the pillow still exists, and will lift up the pillow to retrieve the toy.
Modern technology was not available in Piaget’s time, so he often used motor tasks to test the cognitive understanding of an infant. With the availability of more advanced techniques that can track an infant’s eye movements or rate of sucking in response to stimuli, researchers now know that infants reach cognitive milestone such as object permanence.”
Excerpted from: Turkington, Carol, and Joseph R. Harris, PhD. The Encyclopedia of Learning Disabilities. New York: Facts on File, 2006.