What is the relation between information technology and human development? This is one of the big questions for contemporary developmental scientists. An enormous research literature has documented how information technologies shape human development cognitively (Papert, 1980(Papert, , 1993, socially (Turkle, 1984(Turkle, , 1995, and physically (Harwin and Haynes, 1992). However, how human beings, particularly ordinary children and adults, master information technology cognitively (understanding the Internet, for example), socially (such as building social network), and physically (for example, learning to use a mouse) has not yet been studied adequately and systematically. As a result, dynamic reciprocal interactions between information technology and human development have been often oversimplified as a static one-way process in which information technology controls human beings. While computer scientists are designing human-centered computers that adapt to people rather than the other way around (Dertouzos, 2001), developmental research will soon fall far behind the technological advances if the research continues to focus on how technology affects people rather than on how people interact with technology.We thank Joshua Smith and Heping Hao for their feedback on the early version of this chapter