Adult cognitive development is one of the most important, yet neglected aspects in the study of human psychology. Although the development of cognition and intelligence during childhood and adolescence is of great interest to researchers, educators, and parents, they assume that this development stops progressing in any significant manner when people reach adulthood. In fact, cognition and intelligence do continue to progress in very significant ways. In Developmental Influences on Adult Intelligence, Warner Schaie lays out the reasons why we should continue to study cognitive development in adulthood, and presents the history, latest data, and results from the Seattle Longitudinal Study (SLS), which now extends to over 45 years. The SLS is organized around five questions: Does intelligence change uniformly throughout adulthood, or are there different life-course-ability patterns? At what age and at what magnitude can decrement in ability be reliably detected? What are thepatterns and magnitude of generational differences? What accounts for individual differences in age-related change in adulthood? Can the intellectual decline that increases with age be reversed by educational intervention? From his work on the SLS, Schaie derived a conceptual model that he presents in this volume. The model represents his view on the factors that influence cognitive development throughout the lifespan, and provides a rationale for the various influences that he investigated--genetic factors, early and current family environment, life styles, the experience of chronic disease, and various personality attributes. The data in this volume include the 1998 longitudinal cycle of the SLS. In light of both new data and revised analyses, psychometric and neuropsychological assessments have been linked in long-term data to aid in the early identification of risk for dementia in later life. Schaie also presents new data and conclusions on the impact of personality on cognition.The volume includes correlation matrices and web-access information for select data sets that might be useful for secondary analysis or as examples for exercises in methods classes. Developmental Influences on Adult Intelligence is an important resource for researchers and students in developmental, cognitive, and social psychology.