Final answer:
Kayla has learned the concept of object permanence by realizing that her favorite toy still exists even when it's not visible, as evidenced by her behavior in searching under the blanket.
Step-by-step explanation:
Kayla demonstrates object permanence when she lifts the blanket to find her toy. This concept, introduced by Jean Piaget, describes an infant's understanding that objects continue to exist even when they are out of sight. Initially, very young infants might act as though an object no longer exists when it is hidden.
However, typically by the age of 5 to 8 months, they start to realize that the object still exists and this is precisely what Kayla showed by finding her toy under the blanket. This is distinct from concepts like conservation (understanding that quantity doesn't change despite changes in form), egocentrism (difficulty seeing other perspectives than one's own), and attachment (developing close emotional bonds), which are other aspects of cognitive and emotional development.