In infancy, which psychological concept is evident when a child knows an object still exists when it is out of sight?

The concept being described is object permanence, which is a fundamental cognitive development milestone in infants. Object permanence refers to the understanding that objects continue to exist even when they cannot be seen, heard, or touched. This cognitive ability typically develops in infants around 8 to 12 months of age and is a crucial aspect of their understanding of the world.

When an infant looks for a toy that has been covered or moved out of sight, it demonstrates that they have formed a mental representation of the object and understand that it still exists, even though it is no longer visible. This development is significant as it reflects the infant's growing cognitive abilities and their understanding of the permanence of the world around them.

Other concepts mentioned, like visual perception, causality, and symbolic thought, do play roles in children's psychological development but do not specifically pertain to the understanding of object permanence. Visual perception relates to how children see and interpret visual information, causality deals with understanding cause-and-effect relationships, and symbolic thought involves the ability to use symbols or images to represent objects or ideas. However, these concepts do not capture the essential ability to recognize that objects continue to exist independently of their immediate visibility, which is the essence of object permanence.