The longest relationship most of us will have is with a sibling – someone who, unlike a friend or partner, we didn’t choose to bring into our lives. Ninety percent of people grow up with a sister or brother watching them struggle through awkward adolescence into adulthood, sharing a home, parents and family resources. It’s no wonder these relationships can be so close and supportive but often frustrating, competitive and contentious.

Today we explore all sides of our sibling relationships and how they shape who are from children to adults. We’ll talk about why people from the same family can be so different, ways to heal old resentments and jealousies, and how to stay close to our siblings – if we want to – when life pulls us apart.

KARL PILLEMAR, Professor in the Department of Psychology, Professor of Gerontology in Medicine at Weill Cornell Medicine, and Senior Associate Dean for Research and Outreach in the College of Human Ecology.

LAURIE KRAMER, Professor of applied psychology at Northeastern University and a clinical psychologist.