If you think you have a lot going on inside your head, just talk to a three year-old. A toddler’s brain is twice as active as a fully matured adult brain, according to the Centers for Disease Control and Prevention. That’s why the first five years of a child’s life are the most important period of development physically, cognitively and emotionally. From gurgling sounds to “mama” and “dada” to playing make believe, we walk you through the ten important milestones of a developing child. And parents, there are things you should be doing to help stimulate your child’s brain. You can find it all in our infographic below.