This summary of the longitudinal research being conducted by Child & Family Research, NICHD, NIH, is dedicated to the many hundreds of families who have participated in the study. Without their interest and investment of time, this work could not be done. Many of you have participated at repeated intervals, and over a period of over 20 years! You have generously adjusted schedules and plans to accommodate us, and have welcomed us into your homes. Most importantly, you have shared yourselves - your family life, personal beliefs and behaviors. Thank you for allowing us to learn from you in many different ways. We hope that it has been interesting and fun for you. It surely has been and continues to be for us. Your perseverance and belief in the ultimate value of this research has been critical to our success. Through your participation, you have made genuine contributions to science. Thank you. We are eternally grateful!
This booklet is also dedicated to the dozens of staff members who have scored the questionnaires, coded the videotapes, and otherwise worked with the data collected throughout the course of the study. This has been a monumental job, requiring tens of thousands of hours of exacting work. Your perseverance, tenacity, and commitment to reaping the riches of the raw data have been remarkable. The job of "translating" videotaped interaction sequences and written responses into numerical data that can be analyzed to reveal patterns of functioning in families is difficult work that occurs in the research "trenches." Only when that work is done can we move to the "high ground" of understanding. Thanks to all who have contributed to this effort and continue to do so. You're the best!
And, finally, a special thank you to Marianne Heslington and Kristen Woo for their charming logo design for the study. It captures the spirit of the work in a special way!
Background and Introduction
What are the NIH and the NICHD?
The National Institutes of Health (NIH) is a federally-funded research institution, located in Bethesda, MD. It is part of the United States Department of Health and Human Services (DHHS). The NIH conducts basic research in the biomedical field. It is made up of 27 different Institutes, each of which focuses on a specific area of health.
One of these Institutes is the National Institute of Child Health and Human Development (NICHD), founded in 1962. The NICHD focuses on issues affecting the growth and development of children, starting from conception and continuing throughout childhood and adolescence, work aimed at bettering the lives of children in the United States, and by extension, children and families around the world. We are proud to be a part of this long-standing and significant effort.
What is the Child and Family Research Section?
Each Institute at the NIH is subdivided into research groups called Branches. Each Branch is further divided into laboratories. Our laboratory is the Child and Family Research Section (CFRS), headed by Dr. Marc H. Bornstein. The staff of the CFRS is made up of developmental and clinical scientists, ranging from those at the doctoral level to those who have just graduated from college. All are trained in the study of children's behavior, with a special emphasis on how to conduct research studies. Many of the younger scientists leave the laboratory to continue their graduate education in this field after spending a year or two with us. Other, more senior members have been with the laboratory since it was founded in 1987.
Dr. Bornstein received his doctorate in psychology from Yale University. Before coming to NIH in 1987, he taught at Princeton University and New York University. He is a world-renowned expert in the study of parenting and child development across cultures. He has published hundreds of research articles in the field's leading journals, collaborated on approximately 100 book chapters, and authored or edited dozens of books including advanced textbooks for developmental science and his five-volume Handbook of Parenting. He is also the Founding Editor of the journal Parenting: Science and Practice. He has served on the editorial boards of dozens of journals and has earned numerous honors and appointments to leadership positions in the field.
What is the longitudinal study of child and adolescent development?
We are studying the course of development from infancy through young adulthood in children who were healthy at birth and who were born into intact families. To date, the general design of this study has included data collection in infancy (5 months), toddlerhood (20 months), the preschool period (48 months), childhood (10 years), early adolescence (14 years), late adolescence (18 years) and young adulthood (23 years). Notably, this study is considered one of the most extensive longitudinal and cross-cultural data collections of child development ever conducted.
Who are the families in this study?
Over 1200 families in the United States and in 12 foreign countries (Argentina, Belgium, Brazil, Cameroon, England, France, Israel, Italy, Japan, Kenya, Peru, and South Korea) have participated, at various ages, in this study. The participants from each country differ, depending on the research questions being addressed in each one. For example, families living in the city and on the kibbutz were recruited in Israel. In Belgium, families where children were growing up speaking one versus two languages were selected. In the United States, we recruited families with firstborns and secondborns, adoptive families, adolescent mothers, and mothers using different types of childcare, among others. We have also enrolled families in the U.S. representing different immigrant groups including Japanese American, Korean American, and families from several South American countries.
Importantly, all participants are volunteers---who respond to recruitment efforts and then decide that they want to enroll. This is desirable because it means that everyone who participates does so willingly, without any pressure, because they are interested in the type of knowledge that our research will yield. It also means, however, that none of our samples of families is completely representative of all families. This "self-selection" poses some limitations on how we can generalize from the findings of our studies. We must carefully describe our groups of families so that the consumers of our research know exactly who contributed information to each study. We can never claim that the patterns of development that we identify across our samples will apply to all children and families everywhere. This same restriction applies to most research in the field of child development; still, studies using "self-selected" samples make vital contributions to the field.
In any scientific area, knowledge is gathered incrementally, over time and across studies. No single investigation yields final answers. It is when multiple studies, carried out with different groups of families, yield similar (convergent) results, that a valid and reliable "big picture" begins to emerge. Our work, like that of scientists around the world, contributes to a larger – and constantly growing – body of knowledge and understanding about all facets of family life. A single study, which can take a very long time to do, is just a tiny piece of the puzzle. Individual studies (puzzle pieces) that are well-constructed, defined, and more differentiated, come together to reveal a clearer final picture. These careful, well-executed studies are harder and more time-consuming to conduct. Scientific research is an ongoing process; it is never complete. This is at once the frustration, the challenge, and the ultimate reward of our work.
What do we measure and how do we measure it?
In each cultural sample, children were seen at the same ages, and comparable information was collected. This allows us to study families within each culture, but we also to compare families across cultures.
Infancy: 5 Months
In infancy, we conducted a naturalistic home observation of mother and infant in the home setting. Visits were an hour in length, and mothers were asked to go about their normal routine during that time. Typically, no one else was present during the visit. Our goal was to capture a "snapshot" of the mother-infant dyad and of the typical daily circumstances in which the baby was being reared. Even though the activities of individual mothers and babies varied widely, for each family the activities were typical; they were daily events in familiar surroundings. As a result, we are confident that the behavior that we observed was truly representative.
Toddlerhood: 20 Months
When the infants were toddlers, we again visited the family in the home setting. We attempted to maximize the probability that the babies would act naturally by seeing them in their familiar environment, but we wanted to be sure to collect comparable information from all families, so we conducted a more standardized visit, (i.e., it was the same for everyone rather than being naturalistic). We assessed symbolic functioning in the children in the areas of language development and play.
In both areas, children gradually develop the ability to deal with abstractions. In language, words and their combinations are symbols that take on meaning and are central to communication, thinking, and reasoning. In play, children move from exploratory behavior to pretense play and, in this way, manipulate ideas and emotions through their play. Both areas are important windows on how children's minds are developing.
Preschool Period: 48 Months
At age 4, we broadened our data collection to include measures of a variety of aptitudes that all children possess to varying degrees. The notion of "multiple intelligences" was proposed by Dr. Howard Gardner at Harvard University. According to this theory, successful human functioning depends on a person contributing to the needs of the social group in which he or she is living. All people have strengths, and these areas of skill vary considerably among individuals.
Instead of thinking of "intelligence" as that which is measured by traditional I.Q. tests, Dr. Gardner proposed that there are a number of different types of intelligence, all of which are equally important for people's productivity, success, and well-being. These are: linguistic intelligence (writer, orator, journalist), logical mathematical intelligence (scientist, mathematician), musical intelligence (singer, violinist), spatial intelligence (geographer, surgeon, architect), bodily-kinesthetic intelligence (athlete, dancer, craftsman), interpersonal intelligence (teacher, politician, clergy), intrapersonal intelligence (self-awareness), and naturalist intelligence (biologist, farmer, fisherman). During a visit to our laboratory, we assessed a variety of these areas of functioning in the 4-year-old children.
Childhood: 10 Years
The next data collection occurred when the children were 10 years old. The middle childhood years (ages 6-12) are a time of major transition in human development which results from both maturation and socially prescribed transitions. This can be seen in several realms including: cognitive competence and the growth of knowledge; social roles and relationships; increased vulnerability to stress; altered functions of the self; and self-regulation and social responsibility.
In addition to studying the child's language and cognitive abilities at this age, we added a wider variety of measures of social-emotional functioning, including: the child's attachment to both parents; behavioral adjustment; coping skills; capacities for empathy, emotional expressiveness, and prosocial behavior; relationships with peers; relationships with siblings; self-esteem; knowledge of sex typing; and temperament. Various aspects of the child's immediate social environment – marital adjustment, parenting behavior, sibling relationships, and overall family functioning – were also assessed. In addition to mothers and children, fathers and school-teachers were invited to participate, greatly enriching our view of the child's world.
Early Adolescence: 14 Years
The transition to adolescence constitutes another significant milestone in the development of children, evident in nearly all domains of functioning. Early adolescence is a time for forging new relationships with peers, defining and testing the limits of intimate relationships both with peers and with parents and siblings, and seeking to understand one's individual identity in the midst of these changing relationships.
During this period of development, changes in one domain are often associated with changes in one or more other domains. In the cognitive domain, thought processes and abilities undergo important structural changes as children approach the age of fourteen. It is during this time that children become capable of the more complex, abstract reasoning that constitutes the foundation of adult cognition.
At the same time, the body undergoes significant biological maturation with the onset of puberty beginning around age ten and accelerating throughout early adolescence. The combination of these developmental changes has implications for children's social and emotional development during this period.
At age 14, the teen and mother visited our laboratory for one visit. They were asked to work on several tasks and were also interviewed. Also, the teens, mothers, and fathers all completed questionnaires for us; these data assessed teen functioning, parent-child relationships, parental attitudes, and family functioning. By this stage, data collection had become very wide-reaching indeed!
Late Adolescence: High School Graduation
Late adolescence constitutes another significant period in development evident in nearly all domains of functioning. In addition to the continued growth and development of cognitive abilities and social networks, the late teen years mark the end of childhood proper as children finish their secondary school education and transition out of the home into the larger world. This period of "launching" is significant for all members of the family, and all relationships within the family undergo change and adjustment. Since a major goal of parenting and of children's development is to prepare the youngster for the transition to autonomous functioning, the data that have been collected (in infancy, toddlerhood, the preschool years, middle childhood, and early adolescence) in this longitudinal study will contribute to a rich understanding of the factors that are associated with successful transitions.
Information is collected from teen, mother, and father during the spring of the year that the teen graduates from high school. All data collection takes place online through a website that links with the NICHD database. Teens complete 4 sets of questionnaires, while mother and father each complete 2 sets, working from the comfort of their own homes.
Young Adulthood: 23 Years
Young adulthood constitutes another significant period in development evident in nearly all domains of functioning. Young adulthood is marked by emotional, physical, and financial disengagement from the family of origin. Managing this disengagement is a thorny process for both children and parents, and some manage it better than others. While disengaging from the family of origin, young adults establish closer and deeper connections to friends and romantic partners, and set down the path they intend to follow through adulthood (what they will do for a living, whom they are going to share their life with, and so forth). This period is significant for all members of the family of origin, and all relationships within the family undergo change and adjustment. Because a major goal of parenting and of children’s development is to prepare the youngster for the transition to autonomous functioning, these data along with the data already collected (in infancy, toddlerhood, the preschool years, middle childhood, and early and late adolescence) in this longitudinal study will contribute to a rich understanding of the factors that are associated with both successful transitions and less optimal outcomes.
Information is collected from teen, mother, and father 5 years after the previous data collection point. All data collection takes place online through a website that links with the NICHD database. Young adults complete 3 sets of questionnaires, while mother and father each complete 2 sets.
What are we learning?
Cleary, this longitudinal, cross-cultural study is very extensive, and it is generating huge amounts of information. After a family is visited at a given point in time, the information collected from it must be "reduced," meaning that it must be coded, entered into the computer, organized, checked for missing answers, etc. Until all of this cleansing of the data occurs, the information cannot be submitted to statistical analysis.
Furthermore, data collected at a given point in time cannot be analyzed until all of the families in the study have been seen at that age. Once complete data from all participants at a given age was collected and reduced, statistical analysis occurs, leading to the writing and publication of a scientific report. Analysis can take months and the formal publication process can take a year and more. All of this is to say that there can be a very long hiatus between when a given family is seen and the publication of study results. As a particularly extreme example of how labor-intensive this study has been, each hour-long videotape of mother and infant at 5 months was coded 11 times using multiple behavioral indices. We estimate that coding of the U.S. sample alone took over 10,000 hours!
Whom does this study benefit and how?
The results of studies that are carried out at the National Institutes of Health belong to the American public, since NIH is a federally funded institution. Though all research at NIH is intended to benefit the public, the reports of studies are not typically shared with the public directly. Rather, they are shared with the scientific, medical, and academic communities through published reports, books, teaching, and talks given at scientific meetings. In this way, the knowledge gained from individual investigations flows into the general fund of knowledge in many fields.
The reports from this particular study are usually published in highly respected journals in our field, such as Child Development, Developmental Psychology, and Parenting: Science and Practice. The results may also be published as monographs, books, or chapters in books designed for doctors, researchers, educators, or college and graduate students. The scientists in our laboratory also attend professional meetings every year, where we present our research to colleagues from across the United States and around the world.
So how does this information finally benefit the American public directly? Sometimes scientists at NIH are directly involved in the public dissemination of information. Occasionally, for example, they are called to testify before Congress on issues related to their area of expertise. Some scientists are also involved in creating programs that attempt to translate the findings from research into programs for children and parents (for example, Head Start). Scientists are also routinely interviewed by newspapers, magazines, and television stations that are preparing articles and programs for the public to read and view.
Mostly, however, the "trickle-down" of information comes to the public through contact with doctors (for example, pediatricians), teachers (for example, childbirth preparation classes or an elementary school reading specialist), and the media (for example, books on child development written for parents and educational programs on TV such as Sesame Street). All of the knowledge of child development that is "out there" is based on research like this longitudinal study, which is why the research is so important.