mains the case that stability is a very good first approximation to the
truth in describing the course of personality traits in adults over age 30,it is also clear that there are exceptions and qualifications: small butreplicable declines in some traits, major changes in some individuals(such as those suffering from Alzheimer’s disease), and a decay of thestability of individual differences over long periods of time.
The second major change, reflected in a new chapter (5), was made
possible by the worldwide acceptance of the FFM. Translations of theRevised NEO Personality Inventory into over 40 languages have beenused to address questions of the cross-cultural generalizability of devel -
opmental trends. Although only cross-sectional studies have so far been
reported, they do much to further our understanding of personality sta -
bility and change.
Finally , another new chapter (10) reports a conceptual advance.
Five-Factor Theory (FFT) is a description of the personality system, po-sitioning traits in the broader context of the person and the world. Ini-tially developed to explain how traits could remain stable as individualscontinued to adapt to a changing world, FFT is supported by cross-cultural, comparative, and behavior genetic evidence. Concepts fromthe theory are used in the last chapter to structure a discussion of the ef-fects of personality on the life course and self-concept. The subtitle ofthis edition of the book reflects the importance we assign to this theo-retical perspective.
Although the main message in our book has endured, a wealth of
new findings and new interpretations have emerged since it was firstpublished. We hope this revised edition gives a sense of the progress thefield has made.viii Preface