Why do Toddlers Hit? Is it genes or environment? Actually, it is 95% genes!

It’s natural for toddlers to hit, but where does this aggression come from? We evolved from humans who could fight and defend their lives, territory and loved ones, and they passed on the ability to survive through aggression, to the next generation. Even newborns feel anger when they need something. In addition, in the later half of the first year, they demonstrate what is called exploratory aggression – curiosity pushes them to
see what reaction hitting or pushing another animal or child will bring. By
toddlerhood, ages one to four years, aggression is at its peak, where one out of
every four interactions between a child and someone else is physical. This is
almost every hour!

Does nurture or nature affect the amount of aggression a child has? Let’s
pretend that a human is like a car. Aggression is like the acceleration a car can
do. We all feel aggression. Self-control is like the brakes. We all have braking
ability too, but in varying amounts. Some people have more acceleration and
some people have more braking power.

Aggression is a function of the brain. The limbic system is the emotional part of
the brain and if we have low serotonin in the limbic system, we have more
aggressive behaviors. The frontal lobes are shaped by inborn temperament, but
the environment (a parent that says, “No! We don’t hit people!”) coupled with
brain development is responsible for suppression of the physical urge of hitting,
pushing and biting.

By age five, children learn about indirect aggression, as the result of their
higher order thinking skills. They can be sneakily aggressive in order to ensure
they don’t get caught, or immediately hit back impulsively. This is a sign of
brain development as it takes higher order thinking skills to weigh out the
consequences in each act. By age five, children do choose how to express
anger.

Hitting relieves tension and may be the reason why parents spank when they
are angry. In a small way, it feels satisfying for a second. However, we also
realize that we are social groups and we can’t be aggressive toward each other
and still get along enough to live together. If we hit, we are group sanctioned;
by isolation, in the form of time-out when we are young, to social ostracism
during the school-age years, and finally, jail, as adults. Isolation is a big
punishment for social mammals whether humans or animals. Societal
disapproval helps children to suppress their acceleration. Young children are
ego-centric and don’t care what others think about them yet. Their impulses
rule their bodies and their brains. By school-age, children are being exposed to
the wider world and care about what people think, so social isolation has a
broader impact on their self-control. Pride, shame, and embarrassment are
effective social tools to keep mammals aggression in check.

As the brain grows, children learn to cope with emotions and develop more self
control. By school age, most children have stopped hitting their friends and
playmates, although the odd lapse against siblings is common until the teen
years. It’s healthy to feel feelings, and express them in better ways such as
words that don’t hurt anyone. The key is to keep repeating what you want them
to do until they begin to take it on themselves. The more children practice calm
down tools, the more they are stored in their memory and come to mind as
they internalize social and group rules. When children are exposed to all ages of
social groups, in extended families and all-age schools, they learn the rules of
controlling aggressive behaviour.

Play fighting does not encourage aggression. In fact, it is useful for
development. Children discover their own limits, and what other people consider
acceptable, and it helps teach self-control. It’s hard to watch as a parent,
because you know one child is going to come to you crying, but it definitely
teaches both children about limits for later.

What is the role of adults: Adults just need to do two things.
Do hold their hands and say “Stop. No. Can you see this hurts your sister?”
“Let’s do this (stomp our feet on the floor) to express our anger.” Children get
to see their effect on others and can choose a non-violent way to express their
feelings. Keep repeating this message after every aggressive event.
Don’t role model hitting, slapping, spanking or any other aggressive
behaviours. Children learn by modeling. Children who are hit, are more likely to
hit others by thinking that those who have power use physical aggression to
wield it.

Most all toddlers grow out of the hitting phase, but whether that is 5, 8 or 13 years depends also on temperament, personality and environment.