Babies are intensely curious about parental responses to their behavior. At this young age, babies begin to do things around the home or childcare setting just to see what will happen and how others will respond. This is one way babies learn about cause and effect and what to expect in their interactions with objects and people. These tests might include crying when their caregivers leave the room or grabbing, dropping, and banging different objects on the floor.
Shelov, S. P. (Editor-in-Chief). (2004). Caring for Your Baby and Young Child: Birth to Age 5. The American Association of Pediatrics. Revised edition. New York: Bantam Books.