INTER-GENERATIONAL STUDIES (IGS)
IGS at IHD - Eight Decades of Tracking Families across Generations
The most famous work from IHD remains the Inter-Generational Studies (IGS) - dating back to 1928 when Jean Walker Macfarlane sampled 250 infants born in the Berkeley area. This sample would long support the so-called Guidance Study and the Berkeley Growth Study. Harold E. Jones, shortly thereafter, launched a parallel sample, informing the Oakland Growth Study. These longitudinal studies allowed Prof. Jones and IHD colleagues to study human learning and maturation at various stages of development, often tracking growth in physical, cognitive, and social-emotional domains.
A breath-taking array of data was collected on each child entering the study, along with their offspring and sometimes grandchildren. Recently cataloging and archiving original IGS files, Institute staff discovered health records, lengthy interview transcripts, and photos of maturing children. Some 94 file cabinets of original data now reside in University of California libraries.
Originally, these child and family samples focused on the biological and social maturation of children. They were later extended to span "the study of the human person, from a developmental perspective, over the entire life span," as IHD director M. Brewster Smith wrote in 1967. Researchers would eventually conduct pioneering work on the role of social and institutional contexts on the individual's long-term development.
One well-know analysis, Children of the Great Depression by sociologist Glenn Elder, delved into the severe vulnerabilities experienced by adolescents, stung by their family uncertainties and watching their fathers going off to war. Jack and Jeanne Block drew on these data to advance theories of adolescent personality, and challenged universalist notions absent the influence of the contexts in which youths were coming of age.
This remarkable data set lives on, informing contemporary theories of human development. IHD's Diana Baumrind has developed one of the world's most widely known theories of child rearing - including the parent's role as authoritarian, permissive, or authoritative - after spending decades analyzing the IGS data. Some of the earliest scientific findings on the causes and consequence of divorce stemmed from these three family cohorts. Phil and Carolyn Cowan are now interviewing surviving members of the original IGS cohorts, now in their elder years. Other scholars at the USC and the University of California, Davis continue to mine this unprecedented data set, now spanning three generations.
The IGS studies have long to sparked innovations in research methodologies. The original archives include mounds of IBM punch-cards and huge magnetic tapes, storing the quantitative results of anthropometrics, IQ testing, and personality scales. John Whiting, then at Stanford University, pushed to compare patterns of early stress experienced by IGS toddlers with those growing up in other societies. Harold Jones pioneered in asking whether exposure to preschool classrooms could advance children's early learning, discovering the problem of selection bias (those parents selecting preschool for their child were not randomly distributed). And Diana Baumrind would develop mixed methods techniques, weaving together coded interview data on parenting practices with measures of children's human performance.
At the heart of the IGS studies is a commitment to longitudinal tracking of children, adolescents, and adults - seeing human development as a complex interplay between the person's capacities and the multitude of contexts that the individual confronts throughout life. Personality psychologists once postulated that the individual's behaviors and outlook on life was fixed. The IGS studies have challenged that - observing remarkable change over the life course. The notion of fixed intelligence has given way to multiple forms of human capacity and potential, thanks in part to the eight decades of analyzing the IGS data files.
IHD researchers advanced the importance of seeing the individual's development as a negotiation with naturalistic environments - not simply studied in air tight laboratory settings. And how we think about the contexts - large and small - which the individual negotiates has become more sophisticated, thanks to IHD's steady investment in longitudinal research.