Overview
Sibling rivalry is competition and conflict between siblings over parental attention, time and resources. It is common and can teach negotiation and empathy. Adler linked sibling position to personality.
📌 At a glance
- Key study
- Dunn & Kendrick (1982)
- Main driver
- Competition for attention
- Related
- Family systems theory
Causes
- A new baby: Dunn and Kendrick documented regression and tantrums in many firstborns.
- Perceived favoritism: differential treatment harms relationships when seen as unfair, even into adulthood.
- Temperament, age gap and gender.
- Family stress.
Better phrasing
| Common line | What the child hears | Better |
|---|---|---|
| "You’re older, share." | My feelings don’t matter. | "You wanted it too. Let’s take turns." |
| "Be like your sister." | I’m being compared. | "You worked hard on this." |
Fair isn’t equal. Faber and Mazlish urged treating each child according to need, without comparison.
What parents can do
Let minor fights resolve, acknowledge feelings while enforcing rules, give each child one-on-one time, and prepare the older child before a birth.
Frequently asked questions
- When is it a concern?
- When one child is persistently victimized or hurt—treat it as sibling bullying.
- My firstborn regressed after the baby came.
- Common; more one-on-one attention usually helps.
- Must I treat them identically?
- No—respond to needs and explain why.
References
- Dunn, J., & Kendrick, C. (1982). Siblings: Love, envy, and understanding. Cambridge, MA: Harvard University Press.
- Faber, A., & Mazlish, E. (1987). Siblings without rivalry. New York: W. W. Norton.
- Jensen, A. C., Whiteman, S. D., Fingerman, K. L., & Birditt, K. S. (2013). "Life still isn’t fair": Parental differential treatment of young adult siblings. Journal of Marriage and Family, 75(2), 438–452.