The packaging notes "Playing is recognized as a critical aspect of child development. Some of the earliest studies of play started in the 1890's with G. Stanley Hall, the father of the child study movement that sparked an interest in the developmental, mental and behavioural world of babies and children. A 2006 study by the American Academy of Pediatrics states that, "free and unstructured play is healthy and, in fact, essential for helping children reach important social, emotional, and cognitive developmental milestones as well as helping them manage stress and becoming resilient."