True or False: A baby’s brain grows to three-quarters of its adult size by the age of two.

True.

Nobody really sets out to measure the size of a baby’s brain, but we can make a few basic conclusions about a baby’s brain growth based on the size of their head. The average size or circumference of a baby’s head at birth is about 13½ in. or 34 cm. In the two years that follow, a baby’s head undergoes the most rapid and significant growth period that it will ever experience in a lifetime; most two-year-olds have a head circumference of around 48 cm. When you look at an average growth chart for a child who has reached the age of 18, you’ll see that the steepest curve is from 0 to 2 years of age.  From the ages of two to 18, a child experiences more growth in the size of their head, reaching its full size at anywhere from 54 to 60 cm.

There are so many factors at play in understanding how a baby’s brain works and develops, but the simple fact that the brain experiences such significant physical growth in the first two years of life gives us an idea of the amazing things that are going on in a baby’s brain. It’s interesting food for thought!