Research by Jean Piaget suggests object permanence develops when a baby is around eight months old. According to Piaget's stages of development, object permanence is the main goal for the sensorimotor stage.

What age is object permanence?

Jean Piaget, a child psychologist and researcher who pioneered the concept of object permanence, suggested that this skill doesn't develop until a baby is about 8 months old. But it's now generally agreed that babies begin understanding object permanence earlier — somewhere between 4 and 7 months.

What stage has no object permanence?

During Stage 2, infants still have no sense of object permanence. If they can no longer see an object or individual, they may look for a moment to where they last saw it, but they won't attempt to find it. At this point in development, the saying "out of sight, out of mind" applies.