Six month olds now understand and are thrilled that they can make things happen! They love toys that make noises when they hit them. Soon (around 8-10 months) your baby will also become aware that what is out of sight is not out of mind. They may wake up at night and cry to get you to come in! You can tell that this is what is happening by how quickly they stop crying when they see you. Let her cry at least 3 minutes before checking. Then just talk or pat but don't pick her up or feed her to prevent this becoming a tiresome habit.
Adapted from Healthy Steps. Edited and Compiled by the Center for Promotion of Child Development Through Primary Care 2011