Siblings fight, siblings make up (or, at least they usually do). Sometimes they grow up together, and often there’s a large gap between how they see the world around them.
However, there’s one thing all sibling relationships have in common. This bond tells us who we are, and it defines how we deal with challenges. That’s why sibling rivalry and sibling dynamics in general deserve a deep dive.
Let’s see how we can learn from those annoying munchkins and become more successful in adulthood (not stuck in those adolescent grudges).
Evolutionary Perspective: Competition Stemmed From Scarcity
Let’s put our thinking caps on and look at this like we’re scientists for a second. From an evolutionary standpoint, sibling competition is not a behavioral flaw. Far from it. It’s an adaptive strategy rooted in survival that formed with our ancestors, far before any of us became a creator for the digital age and got a free video editor to go along with our imagination. We were hairy and rude back then, but the core is pretty much the same.
Human infants are born neurologically immature, meaning there’s very little agency on their part, as we all know, and they are remarkably bad at keeping themselves alive. On their own. If we’re being technical about it, it’s a condition known as secondary altriciality. In plain English, it makes prolonged dependence on caregivers essential.
That’s an obvious vulnerability, right? And because of this vulnerability, parental attention, protection, and responsiveness function as primary survival resources. You have protective parents? You live. If you don’t, then sorry pal, subscribe to the philosophy of reincarnation and hope for the best.
Bowlby’s attachment theory frames this as the child’s drive to maintain proximity to a caregiver who regulates stress, ensures safety, and supports physiological stability. Ever had a clingy child? They know in their heart that the moment they let you go, you might give your resource to something or someone else. Drink your coffee hot, or even poop in peace. Alone. For a minute. What a shock…
Where Do Siblings Come Into Picture?
When siblings coexist, they are essentially negotiating access to the same regulatory system, aka their parents. Across all mammals, when caregiver resources are limited, offspring display increased rivalry behaviors. Why? Because they don’t have a seven eleven on every corner and can’t just get food whenever they need to. Food is for the strong, sorry, junior.
Clingy siblings vocalize more to snatch attention here and there, position themselves closer to the caregiver, and compete for eye contact or touch. In other words, use all tools at their disposal.
Homo sapiens children do the same. Scientifically speaking, they engage in parallel mechanisms: interrupting, escalating emotional bids, or acting out in ways that reestablish proximity, or force mom to come back into contact. So, when your toddler cries because the water is too wet, all they need is a hug. Simple.
CAUTION! Distinction ahead. They don’t need you to try harder to please them. Far from it. They just need a hug… Good, now step away and continue doing what you were doing, and let’s get back to the issue at hand.
But let’s get back to science for a sec. Neurobiologically, sibling competition is reinforced by the developing stress-response system. A child who perceives reduced parental availability experiences a mild threat response. As we know, the human bosy has several ways to protect itself from stress. That includes elevated cortisol, heightened vigilance, etc. That response increases the urgency of retrieving the caregiver’s attention.
From this lens, sibling rivalry becomes a predictable outcome of two or more children seeking co-regulation from the same attachment figure. Rather than pathology, it reflects deeply ingrained survival circuitry. In other words, rivalry to some extent is normal and biologically expected. Predetermined, even.
But let’s look at it from a sociological perspective. Under each age group you’ll find 2 recommendations that might make your day-to-day interactions a bit smoother.
Developmental Milestones and Needs
Sibling rivalry isn’t just THERE from the getgo. It is determined by each child’s developmental stage, their age difference, and lots of other factors. From a sociological perspective, these stages reflect shifting social roles, expectations, and family power structures that shape how children negotiate their place within the household.
1. Early Childhood (2-5): The Struggle for Attachment and Autonomy
During early childhood, rivalry is highly motivated by a conflict between a state of dependence and the development of autonomy. The parents are regarded by toddlers as their social world. When a brother or sister enters into that sacred space (even AND especially a newborn), they are aware of what is about to happen. A reassignment of emotional capital. No toddler in the history of mankind has ever formulated that thought, don’t get me wrong. But they have their own way to let you know, as any parent knows.
All those tantrums titled You love him/her more than me (director’s cut) were nothing more than cries for attention. Fair enough, they don’t remember their infancy and all the attention they needed back then.
Sociologically, the child understands the birth of a brother or a sister as a change in his status with the family structure. The competition manifests as regressive behaviors, clinging, or tantrums, as a demand to be present again and be attended to. Competition at this stage does not revolve around the sibling, but rather the fear by the child of losing social status.
- Prioritize one-on-one micro-moments (5-10 minutes) to reduce attention insecurity.
- Use parallel activities (drawing, blocks) to avoid direct competition and gradually introduce turn-taking. They’ll thank you later.
2. Middle Childhood (6-10): Fairness, Rules, and Social Comparison
In the middle childhood, children gain more understanding of norms, fairness, and equity. Once again, these ideas are not represented in their heads. Instead they are more intuitively viewed and influenced by peer contacts and school cultures.
Competition in this case is based on comparisons: who has more privileges, who is more praised, who has more responsibilities. It is a sociological change in the way of thinking about oneself in comparison to the others. The siblings form reference points of a mini social system where children are trying out concepts of justice, competence and self-worth.
The conflicts between the siblings tend to arise concerning the chores, the success, or the perceived favoritism, which represents an increasing sensitivity to the social roles.
Sibling conflicts often emerge around chores, achievements, or perceived favoritism, reflecting a growing sensitivity to social roles.
- Establish clear, consistent fairness rules for chores, rewards, and screen time.
- Praise individual effort, not comparison (You worked hard, not You’re better than…).
3. Early Adolescence (11–14): Identity, Privacy, and Social Territory
Negotiation of identity and personal boundaries is now rivalry by adolescence. Adolescents desire to be autonomous, to have a presence of their own. Their room, privacy, choices and friendships, are usually touched upon.
Brothers and sisters can be a menace to these spaces physically or symbolically. How? By failing to seek approval to destroy the rooms of one another. But it is pranks, fighting over car seats.
Sociologically, this is a stage at which children re-establish their role within the family structure as they create an alternate identity without the family. Competition is expressed in the form of argument, alienation, or attempts to establish the social identity of the participants in a struggle based on the struggle to establish an emerging social identity.
- Protect personal space and privacy; assign separate responsibilities.
- Involve them in family decision-making to reduce power struggles and reinforce autonomy.
Hopefully, these small steps will help you keep the peace in your home. But, as parents, one thing we know for sure is that peace is relative, and often overrated. Take it one step at a time, and make sure you get yourself a snack today. You deserve it.