The psychological birth of the human infant

How infants develop a sense of reality and relationship through the separation–individuation process — the gradual psychological “birth” of the human infant….

Together with Fred Pine and Anni Bergman, Margaret Mahler researched how infants develop a sense of reality and relationship through what she called the separation–individuation process — the gradual psychological “birth” of the human infant. Her work explores how we come to experience ourselves as separate individuals, while still remaining emotionally connected to others.

Mahler originally proposed an early stage from birth to around one month called the Normal Autistic Phase, a kind of external womb where the infant was thought to be largely inwardly focused. She later dropped this stage as research developed to show that newborns have far greater perceptive and cognitive functioning than she initially believed.

The next stage is the Normal Symbiotic Phase, beginning around the second month. This is a period of the baby’s absolute dependence on the mother or primary caregiver. As Winnicott famously said, “there is no such thing as a baby” — only the baby-and-caregiver unit. In this state of emotional fusion, there is little sense of boundary. The developmental goal is for the infant to begin recognising that their needs and inner sensations can be met by an other.

From around four or five months, the infant begins to look outward with curiosity and alertness. This first sub-phase is known as Hatching. The baby starts to show early agency and interest in the world beyond the caregiver. The task for the mother is to allow autonomy to emerge gradually — without pushing the child away too soon or holding on too tightly.

The second sub-phase begins around nine months and is called Practicing. The baby starts to crawl away, and eventually walk, opening up an entirely new experience of independence. At this stage, the caregiver’s role is to support exploration while remaining emotionally available for “refuelling” when the child returns for reassurance.

The third sub-phase begins around 18 months and is characterised by the toddler’s growing awareness that they are separate, and not omnipotent. This can lead to the Rapprochement Crisis, often seen in tantrums, conflict, and ambivalence. The toddler longs for closeness but also fears being overwhelmed. As language develops, the caregiver is challenged to provide emotional support alongside physical care.

The fourth sub-phase occurs in the third year of life and is called Emotional Object Constancy and Individuality. Here, the child begins to integrate both the good and difficult aspects of others, developing a more stable internal sense of relationship. This supports the formation of the ego and the ability to tolerate frustration, separation, and emotional complexity.

Mahler’s theory is not only about infancy — it offers a powerful lens for understanding adult struggles with closeness, independence, boundaries, and identity. For example, some people may feel anxious when alone, while others may find intimacy difficult or fear being emotionally engulfed.

In psychotherapy, exploring these early developmental themes can help make sense of present-day relationship patterns and support a stronger sense of self. Therapy can provide a safe space to work through fears of separation, develop emotional stability, and build more secure and fulfilling connections with others.

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