Final answer:
Piaget's sensorimotor stage consists of six substages and is focused on infants learning about the world through sensory and motor interactions, including the development of object permanence.
Step-by-step explanation:
Jean Piaget described the sensorimotor stage of cognitive development as having six substages. This stage is the first stage in his theory and spans from birth to about 2 years old. During this period, children learn about the world through their senses and motor behaviors. A key development in this stage is the acquisition of object permanence, which typically begins to emerge between 5 and 8 months of age.