Sibling Relationships During Infancy and Toddlerhood

Infants form early attachments to older siblings, using them as a secure base and seeking comfort during distress.

As infants become more mobile, sibling conflict often increases, typically over toys or parental attention.

Sibling conflict increases further after the younger child turns 18 months.

As toddlers join family interactions, they learn which behaviors annoy or please their older siblings.

Some disagreements become constructive conflicts that siblings resolve through understanding, negotiation, and compromise.

Despite conflicts, prosocial and play-oriented behaviors are more common than rivalry, hostility, and competition.

As older siblings are often dominant, their emotional and social adjustment has a greater influence on the relationship.

Same-sex siblings—especially girls—often display greater closeness and more cooperative play than mixed-sex pairs.

Sibling relationship quality influences friendships. Children with older siblings are better able to manage their thoughts and actions and understand others’ thoughts and feelings.

However, aggressive patterns with siblings can carry into friendships, increasing the risk of bullying or being bullied.