Differences between people are a fascinating and long-standing area of psychological inquiry. However, previous research has largely been confined to studies at the descriptive level. This book tries to explain individual difference, rather than merely describe them. Explanations are derived from two major competing frameworks: the biological and social approaches to individuality. The book is based on the contributions of specialists from Europe and North America invited to represent the biological and social points of view. Thus, a direct confrontation is obtained of two approaches that,...