Babies develop about 80% of their brain growth over the first two years of life, and it's also when all the connections in the brain, what we call the white matter, which is the cables in the brain, grow and develop and connect to the cortex.
A lot of parents don't realize that their baby, all the skills that they have. So they can look at you, they can follow you. They're already starting to imitate you, and through the first few months of life, they're already starting to learn to reach and grasp toys, and to have nonverbal communication with you.