Revision with unchanged content. Theory of mind (ToM) - ability to understand mental states of others - has been hypothesized to be a universal capacity. However, several cross-cultural studies that tested non Anglo-American children with the false-belief tasks found some variations in the developmental time course of ToM. Some of these studies found delays and others found advancements in the non-English speaking children. These results lead to a hypothesis that the neural basis that subserves the culture/language specific ToM may vary depending on the person's cultural/linguistic background. The research described in this book has tested this hypothesis in Japanese and American participants using functional magnetic resonance imaging (fMRI). The results indicate that neural bases of ToM are not entirely universal and the variation is evident as early as 8 years of age. Theoretically, these results may also support the Sapir-Whorf hypothesis that posits that the person's language/culture sculpts his/her thoughts and the world view. This book is addressed to (but not limited to) social, cognitive developmental psychologists, neuroscientists, biologists, neurologists, philosophers, and linguists.