This book is the companion volume to Rethinking Innateness: A Connectionist Perspective on Development (The MIT Press, 1996), which proposed a new theoretical framework to answer the question What does it mean to say that a behavior is innate? The new work provides concrete illustrations -- in the form of computer simulations -- of properties of connectionist models that are particularly relevant to cognitive development. This enables the reader to pursue in depth some of the practical and empirical issues raised in the first book. The authors' larger goal is to demonstrate the usefulness of neural network modeling as a research methodology.The book comes with a complete software package, including demonstration projects, for running neural network simulations on both Macintosh and Windows 95. It also contains a series of exercises in the use of the neural network simulator provided with the book. The software is also available to run on a variety of UNIX platforms.