Peekaboo

Peekaboo uses a joke-like structure: surprise, balanced with expectation.

Linguist Iris Nomikou has compared the game to a dialogue given the predictable back-and-forth pattern. Other researchers have called the game “protoconversation" – a way to teach an infant the timing and the structure of social exchanges.

Object permanence

Peekaboo is thought by developmental psychologists to demonstrate an infant's inability to understand object permanence. Object permanence is an important stage of cognitive development for infants. In early sensorimotor stages, the infant is completely unable to comprehend object permanence. Psychologist Jean Piaget conducted experiments with infants which led him to conclude that this awareness was typically achieved at eight to nine months of age. He said that infants before this age are too young to understand object permanence. A lack of object permanence can lead to A-not-B errors, where children reach for a thing at a place where it should not be.