During this time, babies learn about cause and effect and how they can make things happen. They understand that they can show what they want by making special noises or using gestures and facial expressions. For example, they know that when they smile, mommy usually smiles back. They respond to people who talk or play with them by making sounds, faces, and gestures such as reaching out. They use all the skills they're developing to make an impact on and learn about the world.