More importantly, quality and quantity of a certain act becomes evident. Three new processes of behavior are established and include imitation, play, and affect. The infant begins to imitate simple sounds and gestures. Affect, or outward expression of emotion, becomes evident as the infant begins to develop object permanence. The fourth substage, coordination of secondary schemas and their application to new situations, is transitional.
Infants use the preceding stages as a foundation for adding new cognitive skills.
This stage begins at around nine months of age and lasts until one year of age. Since the infant is gaining motor skills and beginning to explore their environment, the concept of object permanence is advancing. For example, the infant may search for an object hidden behind an obstacle and attempt to remove that obstacle to obtain the object. During this time, the infant can experience events by observing them. The infant with dual sensory impairment has multiple challenges to face.