Midlife — the years between 30 and 70, with 40 to 60 at its core — is the last uncharted territory in human development. This unexplored part of the lifespan has received little attention from students of human development who have tended to concentrate on childhood, adolescence, or old age. Our beliefs about what happens are based on imperfect knowledge and contain many unvalidated premises on which millions of persons make decisions about their lives. These beliefs are transmitted from one generation to the next as our cultural legacy of falsehood and myth about midlife.
Learning the causes of success and failure in adulthood is as important to society as is understanding the problems of childhood and old age — in that middle-aged men and women are responsible for the well-being of the young and the old. When they fail, in physical or mental health, or in their social responsibilities, they jeopardize the welfare of others. Years of heavy investment in socialization and training are lost in the midlife casualties. People in midlife raise the children and care for the elderly. When they succeed, they carry the young and the old along with them.
The primary objective of the Research Network on Successful Development (MIDMAC) was to identify the major biomedical, psychological and social factors that permit some people to achieve good health, psychological well-being, and social responsibility during their adult years. To do this the Network developed an empirical basis for documenting and understanding what happens during these years and compared it with the images of midlife held by men and women across a variety of ages and cultures.
Since this field has been largely unexplored, MIDMAC took the broadest possible view. Investigators from a variety of disciplines — among them psychology, sociology, anthropology, medicine and health-care policy — have explored multiple research pathways to understanding midlife. These include:
- Establishing an empirical basis for documenting what really happens in the middle years — the who, what, when, where, and why of midlife events and the beliefs people hold about them.
- Identifying the factors that determine the course of midlife development, including illness, life events, culture, and work and family interactions.
- Studying the psychological and behavioral strategies people use to understand and deal with events of midlife, focusing specifically on individual differences in the handling of midlife events.
- Developing physical, psychological, and social indicators for assessing and evaluating midlife development.
The MIDMAC research team carried out a number of related studies. One of these is the MIDUS Survey. MIDUS is an acronym for Midlife Development in the United States. The MIDUS survey is a three-hour survey — a combination of a 45-minute telephone interview and mailed questionnaires taking 23 hours to complete. This survey was of 3,000 people who are a representative sample of the U.S. population age 25-74. The survey contained more than 1,100 questions exploring 27 areas of midlife. The results are the first comprehensive scientific description of normal midlife in the United States.
The MIDUS survey is the main study, the core study, in a cluster of 11 related studies being carried out by MIDMAC. Included in this cluster are studies of 1,600 pairs of siblings, 1,000 pairs of twins, an intensive interview study of social responsibility of 50 persons each in five cities, daily diaries of stress events from 1,400 subjects, a study of midlife crisis in 750 persons, and home interviews with 900 members of ethnic and racial minorities in New York City, and Chicago. All together about 8,000 persons are involved. In addition, comparative studies have been carried out in England, Germany and India.
Many different methods were used in these studies: telephone interviews; mailed questionnaires; two-hour face-to-face interviews carried out in homes; intensive six- to eight-hour in-depth interviews; diaries kept by subjects of their daily social contributions, their stress experiences, and certain other events; photographs, for ratings by observers on appearances, e.g., how old the person looks; measures of hips and waists for the waist/hip ratio; samples of salivary cortisol (a stress hormone) to look at stress reactivity; and, for the thousands of twins and siblings, there are tissue samples — from cheek scrapings — now stored in refrigeration, for current and future DNA analyses.
The MIDMAC research program is the most comprehensive study ever of people in midlife, yielding data that will be useful to researchers and policymakers for years to come.