Developmental Influences on Adult Intelligence: The Seattle Longitudinal Study

Developmental Influences on Adult Intelligence: The Seattle Longitudinal Study

Developmental Influences on Adult Intelligence: The Seattle Longitudinal Study

Developmental Influences on Adult Intelligence: The Seattle Longitudinal Study


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 thisdevelopment 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 cognitivedevelopment 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-abilitypatterns? At what age and at what magnitude can decrement in ability be reliably detected? What are the patterns 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 byeducational 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 heinvestigated--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 andneuropsychological 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 forselect 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.


The purpose of this volume is to update my monograph Intellectual Development in Adulthood: the Seattle Longitudinal Study (Schaie, 1996b), which was written to present in one place the program of studies conducted by me, my associates, and my students that has come to be known as the Seattle Longitudinal Study (SLS). I want to make clear from the outset that this volume is not simply an update, but has the major purpose of showing more explicitly how environmental, health-related, and familial influences affect intellectual development across adulthood.

This study originally began as my doctoral dissertation at the University of Washington (Seattle) in 1956. the earlier monograph covered data and findings through the 1991 data collection and included materials that previously had been reported only at scientific meetings but were not available in archival form. the present volume updates data and findings to include the 1998 longitudinal cycle and our efforts to take advantage of our long-term data by linking psychometric and neuropsychological assessments with the hope of contributing to the early assessment of risk for dementia in late life. We have also revisited the impact of personality on cognition. in addition, we provide correlation matrices and information on obtaining Web access to selected data sets from our study that other scientists might wish to use for secondary analysis or as example data sets for exercises in methods classes.

Origin of the Seattle Longitudinal Study

At an early stage of my career, I was confronted with addressing the discrepancies between cross-sectional and longitudinal findings in the study of adult intellectual development. I soon became convinced that this issue needed to be addressed by . . .

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