What indicates that a child has developed a permanent sense of self by age three according to Mahler?

Mahler's theory of child development suggests that by the age of three, a child typically achieves a significant developmental milestone known as object constancy. This concept refers to the child's ability to understand that objects, including people, continue to exist even when they are not directly perceived. This understanding reflects the development of a stable sense of self and the ability to maintain emotional connections despite physical separation.

As the child develops this ability, they also come to recognize their own separateness from others, which is crucial for a permanent sense of self. This process indicates a solidifying understanding of the self as an individual entity and marks an important evolutionary step in emotional and cognitive development. In this context, emotional attachment and independence from caregivers are aspects that evolve with object constancy, rather than prerequisites for its development. Therefore, the demonstration of object constancy and an understanding of separateness are key indicators that a child has reached this critical developmental stage by age three.