Intergenerational Studies – Samples
The Berkeley Growth Study (BGS)
The BGS was initiated by Nancy Bayley in mid-1928. Sixty-one infants were enrolled between September 15, 1928 and May 15, 1929 to trace early mental, motor, and physical development during the first years of life. An additional 13 infants were enrolled in the BGS within 3 years of the start of the study, bringing the final sample size to 74.
Data collection in the BGS began within 4 days of an infant's birth as anthropometric, neurological, and physiological measurements were made in the hospital by the study pediatrician. Participating infants were assessed at IHD every month from 1 to 15 months of age, every 3 months from 18 through 36 months of age, annually from 4 through 7 years and then annually from 8 to 18 years of age. In adulthood the participants were measured at 21, 25, 30, 36, 52 and 72 years of age. The BGS was the most measurement intensive IGS study.
The Guidance Study (GS)
The GS began in early 1928 under the leadership of Jean W. Macfarlane. The 248 original participants in the GS were drawn from a survey of every third birth in Berkeley from January 1, 1928 through June 30, 1929. The initial nature of the GS was a six-year project with the goal to (a) document the frequency of occurrence of behavior and personality problems in a cross-sectional sample of young children during the preschool years, (b) identify the biological and environmental factors that were associated with the presence or absence of such behavioral problems, and (c) estimate the effects of guidance activities with the parents of these children.
The guidance activities consisted of intensive and extensive discussions with parents about child-training procedures conducted during home visits that occurred every three months. But, the scope of factors that might impact on child behavioral problems was broad, as the project sought to document the effectiveness of the guidance activities in the context of family member personality, interpersonal relationships, health, background, and social status variables, among others. Effects of the guidance activities were to be assessed when the child was 6 years of age, at the time of transition to the school years.
The home visits began when infants were 3 months of age and continued through 18 months of age. When the infants were 21 months of age, half of the sample (N = 124) was assigned to a guidance condition and the remaining half of the sample (N = 124) was assigned to a control condition. Parents of the infants in the guidance condition then engaged in intensive discussions with the public health nurses who conducted the home visits and with other project staff. An initial, intensive assessment of the infants and their parents was conducted when the infant was 21 months of age. Thereafter, infants and parents were interviewed and tested every 6 months from child age 2 years through 4 years and then annually from 5 to 18 years of age. In adulthood, the GS participants were assessed at ages 30, 40 and 52.
The Oakland Growth Study (OGS)
The Oakland Growth Study (OGS) began in 1931 under the guidance of Harold E. Jones, Mary C. Jones, and Herbert R. Stolz. A total of 212 students in five elementary schools in Oakland, California, who had signified their intention to attend the junior high school selected as the center of observation for the study. The goal of the OGS was to study of normal adolescence, particularly physical and physiological maturation and peer relationships. When initial measurements were taken in 1932, the participants ranged in age from 10 to 12 years, and thus were, on average, 8 years older than the GS and BGS participants. Participants in the OGS were assessed semiannually during the six years of junior and senior high school. In adulthood, the OGS participants were assessed at ages 38, 48 and 60.