Chapter 6 proposed a psychoanalytic model for the development of full subjectivity, closely linked to the quality of interaction between parent and child. A clinical illustration was offered to show that, for internal reality to be experienced as truly representational rather than as either totally real or totally unreal, the object's mirroring of the child's internal reality, preferably in a playful manner, was a prerequisite. In this chapter, the psychological underpinnings of the processes involved in playful mirroring interactions between child and caregiver are elaborated in the context of a further case report. It is argued that the specific features of interactions that effect a change in the quality of internal representation involve the caregiver creating "marked externalizations" of the child's internal states with the key qualities of separating or decoupling internal experience from physical reality, offering a sense of control over the experience and potentially modifying the content of the experience in the direction of increased pleasure or wish fulfillment. Marked parental mirroring in the context of pretend play or empathic pro-social actions offer early opportunities for the infant to encode features of markedness of expressions (signaling "nonconsequentiality" and decoupling from physical reality), content modifications (leading to reduction of unpleasure and wish fulfillment), and the en292hancement of agentive aspects (which exert control and mastery over affective experience). Such interactions may provide important experiential preconditions that facilitate the emergence of the active use of these features for emotional self-regulation by the infants themselves.