What is the concept of an 'unfinished brain'?

The concept of an 'unfinished brain' refers to the notion that humans are born essentially incomplete, with significant brain development occurring after birth. This 'unfinished' state underscores our dependency on caregivers for attachment, which shapes our emotional and social foundation for life.

What can I do to support my child's early brain development?

Engage in nurturing, responsive interactions with your child to support their early brain development. This approach fosters secure attachment, which is crucial as it shapes the blueprint for their later emotional and social life, laying a stable foundation for future growth.

Why is the first two years of life critical for brain development?

The first two years of life are critical for brain development because this is when our brains undergo enormous growth, developing up to two million new neurons and neural connections per second. This rapid development occurs primarily in the right hemisphere, which lays the foundation for our emotional and social lives, making attachment to caregivers essential.

3.1: The Unfinished Brain: Why the First Two Years of Life Decide Everything

Last updated on 24 Nov 2025

To understand why early attachment experiences shape our entire lives, we must return to the beginning—to the biological starting point with which we're all born. It's crucial to grasp the magnitude of the development we humans undergo after birth.

We Are Born "Unfinished"

Unlike many other species, humans come into the world essentially unfinished. Our brain is still relatively small at birth so that we can pass through the birth canal at all. The real explosion of growth only happens afterward, in a new world we must learn to adapt to.

In the first years of life, our brain undergoes enormous growth—so rapid that during the first three years, we develop up to two million new neurons and neural connections per second. This incredible pace of development is designed to allow us to adapt to vastly different cultures, environments, and societies.

The Right Hemisphere Takes the Lead

A crucial insight about the first two years—the time before children can speak—is that this development takes place primarily in the right hemisphere. It is the nonverbal, holistic hemisphere that takes the lead during this phase. It’s responsible for linking the body and the brain and lays the foundation for our nervous system, digestion, and capacity for self-regulation.

The Fundamental Contradiction

Here we encounter a fundamental contradiction that shapes our entire lives: Although we possess this astonishing capacity for growth and learning, after birth we are almost completely helpless and dependent.

It’s precisely this contradiction—the immense learning potential on one side and total dependency on the other—that makes attachment to our caregivers so crucial. The way this early, pre-linguistic, right-hemispheric development unfolds creates the blueprint for our later emotional and social life. It determines whether we develop a stable or unstable foundation for everything that follows.

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