“The Future
of Longitudinal Studies:
What we know; What we don’t know; What we need to
know”
A Brief Historical
View of Longitudinal Studies: Berkeley and Beyond
Thursday, March 20, 2003
Ravenna Helson
University of California, Berkeley
Most initial longitudinal studies examined men. To study women’s
development, the Mills Longitudinal Study of Women followed a cohort
of women from 1958--when they were about to graduate from Mills
College--through the present (into the twenty-first century). The
study was initially titled, “Creativity, Leadership, and Plans
for the Future in Women,” and aimed to determine whether women
have “creative personalities.” In addition to collecting
self-report ratings (e.g., about parents, health, dating), teachers
and significant others (and later spouses) made ratings of the women.
One-third of the sample was brought to the Institute of Personality
Research (IPAR) at the University of California, Berkeley for more
in-depth assessment.
These women represented an important cohort, because they developed
in the 1940’s and 1950’s, but experienced the changes
of the 1960’s and 1970’s. They also developed against
the backdrop of the women’s movement. Data were used to conceive
of adult development in a social context (e.g., examining conceptions
of maturity; coping and defending).
To determine the generalizability of the Mills sample, data were
compared to intergenerational studies conducted by the Institute
of Human Development (IHD) at the University of California, Berkeley.
The Mills women were born in the late 1930’s and the IHD sample,
which included men and women, was born in the early/late 1920’s.
Comparing datasets was made easier because of the use of some overlapping
tools, such as the California Personality Inventory (CPI) and the
Q-Sort (Block & Block). (Notably, the measures available at
the time reflect cohort effects as well. Dr. Helson noted the importance
of continuously developing new measures.) There were some differences
in personality traits between the two samples, such as that the
Mills sample was less introverted than the IHD sample. Mills women
scored higher than IHD men and women in terms of social vitality/spontaneity
(measured by the “social presence” scale of the CPI),
and reported lower levels of “responsibility” (per the
CPI), which reflected increased individualism among the Mills sample.
Despite these differences, there were similarities in the trajectory
of personality change across the two samples (e.g., “social
presence” decreasing in a linear fashion; “responsibility”
decreasing and then increasing with age, in a curvilinear fashion).
As a greater social psychological literature developed, it became
easier to draw inferences about mechanisms of change in these samples.
Ravenna
Helson's presentation "The
Mills Study and IHD" can be viewed in PDF format, using
Adobe®
Acrobat® Reader®.