This is the second in a series of 10 articles dealing with the different types of loss that doctors will meet in their practice

Infants do not come into the world as “empty slates” but bring with them complex behavioural systems. One system that has been well studied protects the child from danger during the long period of extra-uterine immaturity. It involves the development of mutual attachment behaviour (box), which ensures that the child does not stray far from a caretaker. Infants are active partners in the development of this behaviour, using instinctive behaviours to engage caretakers in protecting them. These include smiling, vocalising, crying, and, later, returning frequently to the secure base of the adult after exploratory forays.1 Infant attachment is at its height at about 3 years of age and then becomes increasingly diffused by the development of other relationships, but it remains important throughout life, with later relationships qualitatively echoing the earlier ones.

For optimal emotional, social, and psychosexual development to occur, children need a warm, secure, affectionate, individualised, and continuous experience of care from a few caretakers who interact with them in a sensitive way and who can live in harmony with each other.