Every Interaction Changes the Brain

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In the previous resources, we explored two important ideas.

Behaviour is what we can observe, but it is not the whole story. And the brain producing that behaviour is not a fixed machine. It is a living biological organ, developing as part of the body and within an ongoing relationship with experience and environment.

This brings us to another principle:

Every interaction changes the brain.

That is a powerful idea, but it needs to be understood carefully.

It does not mean that every conversation, disagreement, hug, difficult morning or moment of frustration produces a permanent or measurable change in a child's brain. Nor does it mean that we can identify what changed in the brain after a particular interaction.

Instead, the principle reminds us that the developing brain is responsive to experience. Interactions with other people form part of that experience.

Development happens over time, through countless experiences interacting with the child's biology, previous learning, relationships and wider environment.

What Do We Mean by “Every Interaction Changes the Brain”?

A living brain is continuously responding to information.

When a child listens, moves, practises, explores, remembers, makes a mistake, solves a problem or interacts with another person, biological processes support that experience.

Learning is therefore not something that happens separately from biology.

When we learn, the biological system involved in learning is also changing.

This capacity for change is often described as neuroplasticity.

But neuroplasticity should not be imagined as the brain being completely rebuilt after every experience. Much biological change is subtle, ongoing and part of normal functioning and development.

So when we say that every interaction changes the brain, we are describing a general developmental principle rather than making a measurable claim about one particular interaction.

A Brain That Responds to Experience

Children do not develop independently of what happens around them.

They encounter sounds, movement, language, people, places, expectations, routines, challenges and opportunities. They experience success and difficulty. They learn what tends to happen next. They gradually build knowledge about themselves and the world around them.

The brain participates in all of this.

Previous experience can influence what a child notices, expects, remembers and learns from later experiences. New experiences then become part of the child's continuing developmental history.

This does not produce a simple chain in which one experience creates one brain change and one behaviour.

Development is much more interconnected than that.

Biology influences experience, experience influences development, development influences future experience, and these processes continue interacting over time.

Relationships Are Part of the Developmental Environment

For children, a large proportion of experience occurs with other people.

Parents, carers, siblings, teachers, friends and other important people form part of the child's developmental environment.

Through relationships, children encounter language, expectations, boundaries, comfort, disagreement, humour, problem solving, encouragement, frustration, repair and countless other experiences.

These interactions matter.

But saying that relationships influence development is very different from saying that relationships determine development.

Parents are important influences in children's lives, but they are not the only influences. Development also involves the child's biology, temperament, abilities, wider experiences, peers, education, physical environment and many other factors.

Influence is not the same as control.

That distinction is essential.

Repeated Experiences Matter, but Development Is Not Mechanical

When experiences happen repeatedly, they can contribute to learning.

A child who repeatedly practises a skill has opportunities to become more familiar with it. A child who regularly encounters predictable routines may gradually learn what those routines involve. A child who repeatedly experiences particular expectations can learn something about what tends to happen in those situations.

But development is not a machine into which adults insert experiences and receive predictable outcomes.

Frequency alone does not tell us what a child is learning from an experience.

Children interpret situations through their own developing abilities and previous experiences. Context matters. Timing matters. Individual variation matters.

This is why phrases such as “this rewired the child's brain” can be misleading.

They can make complex developmental processes sound immediate, permanent and predictable when they are not.

What Parents Can and Cannot Control

Understanding that experience influences development can create an uncomfortable thought for parents:

“If interactions matter, does that mean I have to get every interaction right?”

No.

There is no such thing as a childhood containing only perfectly regulated, perfectly timed or perfectly supportive interactions.

Families experience tiredness, disagreement, stress, competing demands, mistakes and misunderstanding. Parents sometimes respond differently from how they would have liked.

Children are developing within real relationships, not laboratory conditions.

The aim is not perfection.

Nor does neuroscience provide a formula in which a certain number of positive interactions produces a particular developmental outcome.

Parents can influence aspects of a child's developmental environment. They cannot control every experience, every biological process or every developmental outcome.

What About Interactions I Wish Had Gone Differently?

Most parents can remember an interaction they would handle differently if given another opportunity.

Perhaps there was an argument. Perhaps everybody was tired. Perhaps a parent misunderstood what was happening or responded too quickly.

The idea that experience influences the brain should not turn these memories into claims of neurological damage.

One difficult interaction does not allow us to conclude that a particular brain change occurred or that a child's developmental future has been determined.

Development continues.

Relationships continue.

New experiences continue to become part of the child's developmental history.

Adults can also reflect, learn, reconnect and respond differently in future situations.

This is another reason neuroplasticity should be understood as a principle of continuing biological adaptability rather than as a source of parental guilt.

Why Everyday Interactions Still Matter

Rejecting determinism does not mean interactions are unimportant.

Quite the opposite.

Everyday interactions are part of the environment in which development occurs.

Listening to a child, explaining something, setting a boundary, playing together, sharing a joke, helping with a difficult task, allowing another attempt or reconnecting after disagreement all become part of the child's experience.

No single interaction needs to carry the weight of determining a child's future.

It is the broader developmental process that matters.

This gives adults a more realistic way of thinking about their influence.

We do not need to engineer children's brains.

We can try to create relationships and environments in which development, learning and connection have opportunities to occur.

A Short Reflection for Parents

Think about an ordinary interaction with your child rather than an unusually good or difficult one.

You might ask:

1. What was my child experiencing in that situation?
2. What might they have been learning or practising?
3. What was I bringing to the interaction?
4. Was I expecting myself to respond perfectly?
5. If the interaction did not go as I hoped, was there an opportunity to reconnect or try differently later?
6. What remains uncertain about how my child experienced the situation?

These questions are prompts for reflection.

They are not a method for determining what happened inside a child's brain, measuring the quality of parenting or predicting developmental outcomes.