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“The desire to study change is not just a fad although fads do affect studies of change.” Dr. Eichorn discussed the kinds of studies that were the predecessors of current longitudinal research.

Early longitudinal studies, beginning in the 1700’s and through 1900, focused primarily on human physical growth as documented in James Tanner’s book, A History of the Study of Human Growth (Cambridge University Press, New York, 1981). The next wave of longitudinal studies was motivated by political and economic conditions. Specifically, in the United States, the impetus to study the development of youngsters arose (1) out of economic depressions and recessions, and (2) to assist the military in choosing the best soldiers. Large-scale longitudinal studies addressed questions of how individuals cope with changes in the fabric of society (e.g., changes in immunization availability; changes in education level).

In the 1920’s and 1930’s, Lawrence Frank, assistant director of the General Education Board of the Rockefeller Foundation, funded various longitudinal studies through the Laura Spelman Rockefeller Memorial Fund. As funding moved west, Frank offered support to the University of California, Berkeley for longitudinal research. President Camplett, an astronomer, initially refused the money but Frank won him over by threatening to give it to Stanford. Herbert Stolz M.D.was the first Director of the Institute of Human Development at UC Berkeley. On Frank's recommendation, Stoltz appointed Harold Jones, a Columbia University Ph.D., Director of Research. Both Harold and Mary Jones had been mentored at Columbia by Robert Woodworth, a noted experimental psychologist, who chaired the child development section of the National Research Council. Challenges researchers faced at that time included a lack of transportation, telephones, and calculators. In light of these challenges, maintaining continuity of staff was one of the keys to successful completion of longitudinal studies.

As the field of psychology struggled to be recognized as a science, theories of change began to be stated as single theories, even though they really encompassed multiple theories. The spirit of “dustbowl empiricism” was apparent. Also at this time, feuds arose within departments, and a split grew between “clinicians” and “scientists” (reflected more recently in the split between APA and APS). Dr. Eichorn noted that if we are doing good science, there should be more clinicians than scientists, because research should be able to address problems that make a difference. Historically, researchers from multiple fields in addition to psychology were (and should continue to be) involved in studying change, including biologists, social scientist, and public health professionals.

Early longitudinal researchers faced the problem of analyzing longitudinal data as longitudinal rather than as cross-sectional. Researchers still face the problem of capturing trajectories that may not be linear, and analyzing data that may not meet statistical assumptions (e.g., normality). It is important to pool statistical techniques to assist with data analysis and methodological problems. One important recommendation is to retain original data, especially given the huge changes in demographics (e.g., socioeconomic status, more ethnic diversity) that often occur during the course of a longitudinal study, as illustrated by Glen Elder's analyses of the UCB longitudinal data.