Family Dynamics

Mom Loved You Best! The Rise and Fall of Sibling Rivalry

How sibling rivalry develops, and what makes it fade.

Posted Jul 16, 2015

(c) Tempest Photography
Source: (c) Tempest Photography

Siblings, like the sister and brother in this photo, may look alike, share a common home, fiercely defend each other against peers who pick on them on the playground, and love playing together.  Are they inevitably also going to experience sibling rivalry? Even if they grow up in an emotionally healthy family environment?

My client Carla remembered as a teeneager thinking that her mother, whom she loved deeply, loved her youngest sister more than her.  "Look at how my mother laughs at my younger sister’s jokes.  They seem to have such fun together!" she would think.

Carla remembers also the traumatic day, when she was about 5 years old, when her father took her older sister to buy an ice cream cone.  "She’s had one more ice cream cone than me!” Carla wailed unconsolably.  “Now I will never catch up!

Carla did feel, looking back, that her parents had been exceptionally sensitive about prevention of sibling rivalry.  They showered love on all four children. They supported all four of them with chauffeuring to roller skating lessons, scouting events, friends, music lessons, and any and every activity that they thought might foster their children's growth and happiness.  And every thing they did, they did equally. 

Yet still, sibling rivalry had left Carla with memories that came up many years later in a therapy session where she was assessing an issue in her adult life and, to understand it more deeply, thinking about the role of sibling relationships in her earlier years.  

Sibling rivalry is a by-product, at least in some cases, of cognitive immaturities.

Limitations in children’s cognitive development makes these moments of rivalry and despair inevitable.  When Carla had focused  on her mother’s enjoyment of her younger sister, who like the youngest in so many families was a specialist in bringing joy and laughter to them all, she could easily conclude that her youngest sister was number one in her parents’ eyes.

Only as she grew significantly older did Carla realize that if you pick any one dimension, one sibling is likely to be best at that.  Her brother was the best musician. He actually became as an adult a professional musician. Her older sister was the best artist.  She became a prize-winning photographer.

Carla's younger sister, the funny one, continued to score high on being personable.  No wonder her students at the university where she teaches writing skills adore her.

Carla's mother often said to her, “Carla, You’re a great intellectual.”  At the time, that meant that Carla was best at sitting back and ignoring her younger sibs when they were playing loudly while she was trying to read.  Years later though, Carla's adult career did turn out to involve academic studies.

So how do cognitive limitations cause sibling rivalry concerns?

There is an alternative paradigm to "which of us do my parents love the best."  There are many dimensions, not just one, by which children can be special.  Carla's parents, she realized, loved each of their children the very best, each for different reasons.

With regard to the ice cream incident, Carla's rudimentary mathematical understanding had left her certain that if her older sister was ahead by one ice cream cone, her sister's lead would last forever. If she herself had eaten n ice cream cones thus far in her life, and her sister now had had n+1, would that create a permanent lead position for her sister?

Carla's young child's mind could see that subtraction would not solve the problem.  There was no way to take an ice cream cone that her sister had already eaten away from her.  What she had not understand was that addition could solve the dilemma.  At another point in time Carla too would enjoy an extra ice cream cone, and then she and her sister would be even again.

Young minds tend to think also that love is a fixed pie.  If a parent says "I love you" to one child, the sibs can easily hear that love as being taken away from the overall love, leaving less or no love remaining for them.  "If you love him, then you must not love me!" 

Though Carla did not recall suffering this common misfortune, she laughed when we talked about it, saying, "That's a good warning to me.  I guess when I tell any one of our four boys that I love him, I'll make sure to tell any siblings in hearing distance that I love them equally."

My conclusion?  Sibling rivalry is here to stay. 

As hard as parents may try to dole out equal doses of their love to all their offspring, each child still is likely at times to feel left out, less than, or even lost in the crowd.  Parents are never perfect, and even if they were, children's thinking is not up to the task of understanding the complexities of equality and its variants.

In spite of the risks of rivalry though, siblings can bring a big boon to the lives of young children, and throughout a lifetime.  Siblings who play together can be a big part of what makes growing up fun.  As adults, siblings can give each other someone to learn from, to lean on and to celebrate with at life's milestones.  In the senior years, aging siblings  together can look back on their lives, share their history, and make sense of it all.


Susan Heitler, Ph.D. is author of, a website that teaches couples the skills for marriage success.