Pēpi develop separation and stranger anxiety during their first year. These new responses are linked to other emotional and cognitive development happening at this time.

Pēpi can form secure attachments with either or both parents.

Most babies develop ‘separation’ and ‘stranger’ anxiety in the second half of their first year. Separation anxiety is when a baby becomes anxious or upset when they’re separated from the person who cares for them the most — often their mum.

Stranger anxiety is when a baby becomes worried or fearful when someone they don’t know approaches them. Babies are now able to assess situations and respond in more complex ways. These new responses are linked to other emotional and cognitive development happening at this time.

Secure attachment and social referencing

At this age, most pēpi have reached an important milestone in the development of an emotional tie or attachment to their mother. Babies with a healthy attachment relationship prefer being near their mum, because mum is the person who helps them with their physical and emotional needs.

They may move away from mum to explore, but they’ll look back at her face for reassurance when they’re not sure about something. This is called ‘social referencing’.

Person permanence

By this age, most babies have developed an understanding of person permanence (that people still exist when they can’t be seen). At earlier stages, pēpi had to be able to physically see their parent to know they existed. They can now hold a picture of that person in their mind.

When baby can’t see a familiar face, they may become upset and fearful in response to the separation. However, it’s still better for a parent to tell baby they are leaving, rather than hoping pēpi won’t notice them going.

If the parent is leaving baby in the care of a trusted person, this person needs to acknowledge baby’s feelings — ‘You’re feeling sad and scared that mum/dad/carer have gone for a little while. They will be back soon.’ If possible, it’s better if long periods of separation can be put off until pēpi is older.

With their new understanding of cause and effect, babies begin to understand that their parent is likely to reappear if they cry or call out. Increased motor development also means that they may crawl to find them. Over the first couple of years, babies gradually learn to trust that the people that love them will eventually return.

Stranger awareness

This preference for the familiar person is also linked to stranger awareness. Now they are the most important person in their life, pēpi can become anxious and upset when an unfamiliar person comes towards them.

Although parents may feel concerned by these new responses, separation anxiety and stranger awareness are very normal stages of development.


  • ‘Separation anxiety’ is when babies become upset when they are separated from their parents.
  • ‘Stranger anxiety’ is when babies become upset when an unfamiliar person approaches them.
  • Separation and stranger anxiety are linked with the development of an attachment relationship, and the development of object permanence, and cause and effect.