encounters (such as parties with dolls), or flirting. Modern findings in neuroscience suggest that play promotes flexibility of mind, including adaptive practices such as discovering multiple ways to achieve a desired result, or creative ways to improve or reorganize a given situation (Millar, 1967; Shonkoff & Phillips, 2000). As children get older, they engage in board games, video games and computer play, and in this context the word gameplay is used to describe the concept and theory of play and its relationship to rules and game design. In their book, Rules of Play, researchers Katie Salen and Eric Zimmerman outline 18 schemas for games, using them to define "play", "interaction" and "design" formally for behaviorists. Similarly, in his book Half-Real: Video Games between Real Rules and Fictional Worlds, game researcher and theorist Jesper Juul explores the relationship between real rules and unreal scenarios in play, such as winning or losing a game in the real world when played together with real-world friends, but doing so by slaying a dragon in the fantasy world presented in the shared video game. Play is explicitly recognized in Article 31 of the Convention on the Rights of the Child (adopted by the General Assembly of the United Nations, November 29, 1989), which declares: Parties recognize the right of the child to rest and leisure, to engage in play and recreational activities appropriate to the age of the child and to participate freely in cultural life and the arts. Parties shall respect and promote the right of the child to participate fully in cultural and artistic life and shall encourage the provision of appropriate and equal opportunities for cultural, artistic, recreational and leisure activities. History of childhood playtime American historian Howard Chudacoff has studied the interplay between parental control of toys and games and children's drive for freedom to play. In the colonial era, toys were makeshift and children taught each other very simple games with little adult supervision. The market economy of the 19th century enabled the modern concept of childhood as a distinct, happy life stage. Factory-made dolls and doll houses delighted young girls. Organized sports filtered down from adults and colleges, and boys learned to play with a bat, a ball and an impromptu playing field. 20th Century With the rise of motor vehicle traffic in the 20th century, teenagers were increasingly organized into club sports supervised and coached by adults, with